\u7f51\u4e0a\u6709\u4e0d\u5c11\u6587\u7ae0\u89e3\u8bfb\u4e86Disney\u7684BRDF\u516c\u5f0f\uff0c\u4f46\u4e2a\u4eba\u89c9\u5f97\u89e3\u8bfb\u7a0b\u5ea6\u8fd8\u4e0d\u591f\uff0c\u5e76\u4e0d\u6613\u61c2\u3002\u5f53\u7b14\u8005\u770b\u5b8c\u8fd9\u4e9b\u6587\u7ae0\u518d\u53bb\u5b9e\u73b0Disney BRDF\u65f6\u53d1\u73b0\u5149\u662f\u8fd9\u4e9b\u516c\u5f0f\u5e76\u4e0d\u591f\uff0cDisney\u505a\u4e86\u66f4\u591a\u7684\u5904\u7406\u3002\u8fd8\u9700\u8981\u641e\u6e05\u695aDisney\u7684\u5404\u79cd\u63a7\u5236\u53c2\u6570\u662f\u5982\u4f55\u4e0e\u5176\u516c\u5f0f\u914d\u5408\u7684<\/p>\n
\u81ea\u8fea\u58eb\u5c3c\u5728SIGGRAPH 2012\u4e0a\u63d0\u51fa\u4e86\u8457\u540d\u7684\u201c\u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\uff08Disney Principled BRDF\uff09\u201d\u4e4b\u540e\uff0c\u7531\u4e8e\u5176\u9ad8\u5ea6\u7684\u6613\u7528\u6027\u4ee5\u53ca\u65b9\u4fbf\u7684\u5de5\u4f5c\u6d41\uff0c\u5df2\u7ecf\u88ab\u7535\u5f71\u548c\u6e38\u620f\u4e1a\u754c\u5e7f\u6cdb\u4f7f\u7528\uff0c\u5e76\u6210\u4e3a\u4e86\u6b21\u65f6\u4ee3\u9ad8\u54c1\u8d28\u6e32\u67d3\u6280\u672f\u7684\u4ee3\u540d\u8bcd\u3002Disney BRDF\u5176\u9ad8\u5ea6\u7684\u901a\u7528\u6027\uff0c\u5c06\u6750\u8d28\u590d\u6742\u7684\u7269\u7406\u5c5e\u6027\uff0c\u7528\u975e\u5e38\u76f4\u89c2\u7684\u5c11\u91cf\u53d8\u91cf\u8868\u8fbe\u4e86\u51fa\u6765\uff08\u5982\u91d1\u5c5e\u5ea6metallic\u548c\u7c97\u7cd9\u5ea6roughness\uff09\uff0c\u8ba9\u7f8e\u672f\u66f4\u5bb9\u6613\u7406\u89e3\u6bcf\u4e2a\u63d0\u4f9b\u7684\u53c2\u6570<\/p>\n
\u672c\u8d28\u4e0a\uff0cDisney Principled BRDF\u6a21\u578b\u662f\u91d1\u5c5e\u548c\u975e\u91d1\u5c5e\u7684\u6df7\u5408\u578b\u6a21\u578b\uff0c\u6700\u7ec8\u7ed3\u679c\u662f\u57fa\u4e8e\u91d1\u5c5e\u5ea6\uff08metallice\uff09\u5728\u91d1\u5c5eBRDF\u548c\u975e\u91d1\u5c5eBRDF\u4e4b\u95f4\u8fdb\u884c\u7ebf\u6027\u63d2\u503c<\/p>\n
<\/p >\n<\/p><\/noscript>\nDisney BRDF\u53ef\u89c6\u5316\u65b9\u6848<\/h1>\n\u5728BRDF\u53ef\u89c6\u5316\u65b9\u9762\uff0c\u8fea\u58eb\u5c3c\u5728\u5206\u4eab\u4e2d\u63d0\u51fa\u4e86\u4e09\u4e2a\u65b9\u9762\u7684\u5de5\u5177\u4e0e\u8d44\u6e90<\/p>\n\nMERL 100 BRDF\u6750\u8d28\u5e93\n\u6db5\u76d6\u5404\u79cd\u6750\u8d28\uff0c\u5305\u62ec\u6cb9\u6f06\uff0c\u6728\u6750\uff0c\u91d1\u5c5e\uff0c\u7ec7\u7269\uff0c\u77f3\u6750\uff0c\u6a61\u80f6\uff0c\u5851\u6599\u548c\u5176\u4ed6\u5408\u6210\u6750\u8d28\n<\/p >\n<\/p><\/noscript>\n<\/li>\n\nBRDF Explorer<\/p>\n\u4e3b\u8981\u7528\u4e8e\u5206\u6790\u6d4b\u91cf\u6750\u8d28\uff0c\u6bd4\u8f83\u73b0\u6709BRDF\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\n<\/li>\n\nBRDF Image Slice\u5207\u7247<\/p>\n\u5c06\u03b8h\u4e0e\u03b8d\u4f5c\u4e3a\u6a2a\u8f74\u548c\u7eb5\u8f74\uff0c\u5bf9BRDF\u8fdb\u884c\u5efa\u6a21\u76842D\u56fe\u50cf\u5207\u7247\n<\/p >\n<\/p><\/noscript>\n<\/li>\n<\/ol>\nBRDF Image Slice<\/h1>\n\u4e2a\u4eba\u8ba4\u4e3a\u5728\u5f00\u53d1BRDF\u4e2d\uff0cImage Slice\u662f\u6700\u91cd\u8981\u7684\uff0c\u901a\u8fc7\u63a7\u5236\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5728BRDF\u53ef\u89c6\u5316\u65b9\u9762\uff0c\u8fea\u58eb\u5c3c\u5728\u5206\u4eab\u4e2d\u63d0\u51fa\u4e86\u4e09\u4e2a\u65b9\u9762\u7684\u5de5\u5177\u4e0e\u8d44\u6e90<\/p>\n
\u6db5\u76d6\u5404\u79cd\u6750\u8d28\uff0c\u5305\u62ec\u6cb9\u6f06\uff0c\u6728\u6750\uff0c\u91d1\u5c5e\uff0c\u7ec7\u7269\uff0c\u77f3\u6750\uff0c\u6a61\u80f6\uff0c\u5851\u6599\u548c\u5176\u4ed6\u5408\u6210\u6750\u8d28\n<\/p >\n<\/p><\/noscript>\n<\/li>\n\nBRDF Explorer<\/p>\n\u4e3b\u8981\u7528\u4e8e\u5206\u6790\u6d4b\u91cf\u6750\u8d28\uff0c\u6bd4\u8f83\u73b0\u6709BRDF\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\n<\/li>\n\nBRDF Image Slice\u5207\u7247<\/p>\n\u5c06\u03b8h\u4e0e\u03b8d\u4f5c\u4e3a\u6a2a\u8f74\u548c\u7eb5\u8f74\uff0c\u5bf9BRDF\u8fdb\u884c\u5efa\u6a21\u76842D\u56fe\u50cf\u5207\u7247\n<\/p >\n<\/p><\/noscript>\n<\/li>\n<\/ol>\nBRDF Image Slice<\/h1>\n\u4e2a\u4eba\u8ba4\u4e3a\u5728\u5f00\u53d1BRDF\u4e2d\uff0cImage Slice\u662f\u6700\u91cd\u8981\u7684\uff0c\u901a\u8fc7\u63a7\u5236\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
BRDF Explorer<\/p>\n
\u4e3b\u8981\u7528\u4e8e\u5206\u6790\u6d4b\u91cf\u6750\u8d28\uff0c\u6bd4\u8f83\u73b0\u6709BRDF\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\n<\/li>\n\nBRDF Image Slice\u5207\u7247<\/p>\n\u5c06\u03b8h\u4e0e\u03b8d\u4f5c\u4e3a\u6a2a\u8f74\u548c\u7eb5\u8f74\uff0c\u5bf9BRDF\u8fdb\u884c\u5efa\u6a21\u76842D\u56fe\u50cf\u5207\u7247\n<\/p >\n<\/p><\/noscript>\n<\/li>\n<\/ol>\nBRDF Image Slice<\/h1>\n\u4e2a\u4eba\u8ba4\u4e3a\u5728\u5f00\u53d1BRDF\u4e2d\uff0cImage Slice\u662f\u6700\u91cd\u8981\u7684\uff0c\u901a\u8fc7\u63a7\u5236\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
BRDF Image Slice\u5207\u7247<\/p>\n
\u5c06\u03b8h\u4e0e\u03b8d\u4f5c\u4e3a\u6a2a\u8f74\u548c\u7eb5\u8f74\uff0c\u5bf9BRDF\u8fdb\u884c\u5efa\u6a21\u76842D\u56fe\u50cf\u5207\u7247\n<\/p >\n<\/p><\/noscript>\n<\/li>\n<\/ol>\nBRDF Image Slice<\/h1>\n\u4e2a\u4eba\u8ba4\u4e3a\u5728\u5f00\u53d1BRDF\u4e2d\uff0cImage Slice\u662f\u6700\u91cd\u8981\u7684\uff0c\u901a\u8fc7\u63a7\u5236\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u4e2a\u4eba\u8ba4\u4e3a\u5728\u5f00\u53d1BRDF\u4e2d\uff0cImage Slice\u662f\u6700\u91cd\u8981\u7684\uff0c\u901a\u8fc7\u63a7\u5236\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
l<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
v<\/code>\uff0c\u5728\u534a\u7403\u7a7a\u95f4\u5bf9\u4e00\u6c34\u5e73\u653e\u7f6e\u7684\u6750\u8d28\u8fdb\u884cBRDF\u8fd0\u884c\uff0c\u80fd\u76f4\u89c2\u7684\u6d4b\u8bd5\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u9ad8\u5149\u3001Fresnel\u3001diffuse\u3001Grazing Retro-reflection<\/code><\/p>\n\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n\n\u03b8d<\/em>\uff1a\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u901a\u8fc7\u4e0a\u56fe\u4e0d\u96be\u770b\u51fa\uff0c\u8be5\u5efa\u6a21\u4e3b\u8981\u548c\u4e24\u4e2a\u53d8\u91cf\u76f8\u5173<\/p>\n
l<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
v<\/code>\u7684\u89d2\u5ea6\u5dee\u5f71\u54cd\uff0c\u4ece\u4e0b\u5230\u4e0a\u8303\u56f4\u4ece0\u5230180<\/li>\n\u03b8h<\/em>\uff1a\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
l<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
v<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u4e3b\u8981\u53d7\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\uff0c\u4ece\u5de6\u5230\u53f3\u8303\u56f4\u4ece0\u5230180<\/li>\n<\/ul>\nSpecular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Specular Peak<\/code><\/p>\n\n\u89c2\u5bdf\u5de6\u8fb9\u7eb5\u8f74\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u51e0\u4e4e\u4e00\u81f4\uff0c\u90a3\u4e48\u8be5\u7269\u4f53\u7684\u7c97\u7cd9\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u4f4e\u7684\u3002\u6b64\u65f6\uff0c\u76f8\u673a\u89c2\u5bdf\u7269\u4f53\u7684\u9ad8\u5149\u5f3a\u5ea6\u53d6\u51b3\u4e8eL\u3001V\u7684\u89d2\u5ea6\u5dee\u3002\u5f53L\u3001V\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u9ad8\u5149\u8d8a\u660e\u663e<\/li>\n<\/ul>\nFresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fresnel Peak<\/code><\/p>\n\n\u89c2\u5bdf\u9876\u90e8\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0L\u3001V\u7684\u89d2\u5ea6\u5dee\u5728180\u00b0\u5de6\u53f3\uff0c\u8bf4\u660eFresnel\u5f3a\u5ea6\u662f\u975e\u5e38\u975e\u5e38\u9ad8\u7684<\/li>\n<\/ul>\nGrazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Grazing Retro-reflection<\/code><\/p>\n\n\u89c2\u5bdf\u53f3\u4e0b\u89d2\u90e8\u5206\uff0c\u53ef\u4ee5\u53d1\u73b0\u5149\u7167\u5411\u91cfl<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
l<\/code>\u548c\u89c2\u5bdf\u5411\u91cfv<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
v<\/code>\u7684\u89d2\u5ea6\u5dee\u51e0\u4e4e\u4e00\u81f4\uff0c\u8fd9\u90e8\u5206\u63cf\u8ff0\u4e86\u5149\u7ebf\u4ece\u76f8\u673a\u540e\u65b9\u7167\u5c04\u7269\u4f53\u7684\u73b0\u8c61\uff0c\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5c0f\uff0c\u4f1a\u5bfc\u81f4\u6709\u5f88\u5c11\u7684\u5149\u7ebf\u80fd\u8fdb\u5165\u76f8\u673a\uff0c\u4ece\u800c\u5bfc\u81f4\u9634\u5f71\uff1b\u5f53\u5fae\u89c2\u6cd5\u7ebf\u548c\u5b8f\u89c2\u6cd5\u7ebf\u7684\u89d2\u5ea6\u5dee\u8d8a\u5927\uff0c\u56e0\u4e3a\u53d8\u7c97\u7cd9\u4e86\uff0c\u4f1a\u9020\u6210\u8fdb\u5165\u76f8\u673a\u7684\u5149\u7ebf\u6570\u91cf\u66f4\u591a\uff0c\u4e5f\u5c31\u5f62\u6210\u9ad8\u5149<\/li>\n<\/ul>\nDiffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Diffuse<\/code><\/p>\n\nDiffuse\u7684\u5149\u7167\u4e3b\u8981\u6765\u81ea\u4e8e\u5165\u5c04\u5149\u7ebf\u53cd\u5c04\u540e\u5f62\u6210\u7684\u6f2b\u53cd\u5c04<\/li>\n<\/ul>\n\u516c\u5f0f\u89e3\u8bfb<\/h1>\n\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u8fea\u58eb\u5c3c\u4ea6\u91c7\u7528Cook-Torrance\u7684BRDF\u7740\u8272\u6a21\u578b\n<\/p >\n<\/p><\/noscript>\nDiffuse<\/h2>\nDisney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Disney\u8ba4\u4e3aLambert\u6f2b\u53cd\u5c04\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u65e0\u6cd5\u5904\u7406Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Grazing Retro-reflection\u7684\u9ad8\u4eae<\/code>\uff0c\u4e5f\u65e0\u6cd5\u5904\u7406\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5149\u6ed1\u4e0e\u7c97\u7cd9\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u8fc7\u6e21<\/code>\u3002\u4e3a\u6b64Disney\u4f7f\u7528Schlick Fresnel\u8fd1\u4f3c\uff0c\u5f15\u5165roughness\uff0c\u5f00\u53d1\u4e00\u79cd\u65b0\u7684\u6f2b\u53cd\u5c04\u6a21\u578b<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n\u53c2\u6570\uff1a<\/p>\n\n$cos\u03b8_l\uff1aDot(N, L)$<\/li>\n$cos\u03b8_v: Dot(N, V)$<\/li>\n$cos\u03b8_d: Dot(L, H) \u6216 Dot(V, H)$<\/li>\n<\/ul>\nfloat FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u53c2\u6570\uff1a<\/p>\n
float FNoL = SchlickFresnel(brdfData.NoL); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat FNoV = SchlickFresnel(brdfData.NoV); \/\/ \u8fd4\u56de(1-cos\u03b8)^5\nfloat Fd90 = 0.5f + 2 * Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u4f7f\u7528roughness\u8ba1\u7b97diffuse\nfloat Fd = lerp(1.f, Fd90, FNoL) * lerp(1.f, Fd90, FNoV); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fd90<\/code>\u6b63\u6bd4roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
roughness<\/code>\uff0c\u968f\u7740\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u03b8d<\/code>\u7684\u589e\u5927\u800c\u51cf\u5c0f\uff0cFd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fd90<\/code>\u7684\u503c\u53ef\u4ee5\u5927\u4e8e1<\/li>\nFL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
FL<\/code>\u548cFV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
FV<\/code>\u90fd\u9075\u5faa\u83f2\u6d85\u5c14\u73b0\u8c61\uff0c\u5939\u89d2\u8d8a\u5927\uff08\u63a5\u8fd190\u5ea6\uff09\uff0c\u8fd4\u56de\u503c\u8d8a\u5927\uff0c\u6700\u5927\u4e3a1<\/li>\nFd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fd<\/code>\u53d7\u5230V\u3001L\u3001Fresnel\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd190\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8eFd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fd90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\uff08L\u3001V\u89d2\u5ea6\u5dee\u63a5\u8fd10\u00b0\uff09\u65f6\uff0c\u503e\u5411\u4e8e1<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u6f2b\u53cd\u5c04\u548c\u6b21\u8868\u9762\u6563\u5c04\u5177\u6709\u7c7b\u4f3c\u7684\u539f\u7406\uff0c\u5168\u90e8\u7684\u80fd\u91cf\u8fd8\u662f\u6765\u81ea\u4e8e\u6298\u5c04\u5149\u5206\u91cf\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7528\u4e00\u4e2a\u53c2\u6570\u6765\u5728\u4e8c\u8005\u4e4b\u95f4\u8fc7\u6e21\uff0c\u4e5f\u5c31\u662fDisney BRDF\u4e2d\u7684subsurface\u53c2\u6570\u3002Disney BRDF\u4f1a\u8ba1\u7b97\u51fa\u4e00\u4e2a\u6f2b\u53cd\u5c04\u503cFd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fd<\/code>\u548c\u4e00\u4e2a\u6b21\u8868\u9762\u6563\u5c04\u503css<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
ss<\/code>\uff0c\u7136\u540e\u4f7f\u7528\u7ed9\u5b9a\u7684subsurface\u5bf9\u4e8c\u8005\u63d2\u503c<\/p>\n\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5bf9\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u8ba1\u7b97\uff0cDisney BRDF\u5e76\u672a\u4f7f\u7528Jensen BSSRDF<\/a>\u7b49\u590d\u6742\u6a21\u578b\uff0c\u800c\u662f\u7528BRDF\u6765\u8fd1\u4f3c\u8ba1\u7b97\uff0c\u4eceHanrahan-Krueger BRDF<\/a>\u6539\u8fdb\u800c\u6765<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\/\/ \u57fa\u4e8e\u5404\u5411\u540c\u6027bssrdf\u7684Hanrahan-Krueger brdf\u903c\u8fd1\n\/\/ 1.25\u7528\u4e8e\u4fdd\u7559\u53cd\u7167\u7387\nfloat Fss90 = Pow2(brdfData.HoL) * brdfData.roughness; \/\/ \u5782\u76f4\u4e8e\u6b21\u8868\u9762\u7684\u83f2\u6d85\u5c14\u7cfb\u6570\nfloat Fss = lerp(1.f, Fss90, FNoL) * lerp(1.f, Fss90, FNoV);\nfloat ss = 1.25f * (Fss * (rcp(brdfData.NoL + brdfData.NoV) - 0.5f) + 0.5f); \/\/ \u8fd8\u672a\u4e58\u4e0abaseColor\/pi\uff0c\u4f1a\u5728\u6700\u540e\u8fdb\u884c\n<\/code><\/pre>\n\nFss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fss90<\/code>\u4e0d\u8d85\u8fc71\uff0c\u6b63\u6bd4\u4e8eroughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
roughness<\/code>\uff0c\u540c\u65f6\u968f\u7740L\u4e0eH\u7684\u5939\u89d2\u53d8\u5927\uff0cFss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fss90<\/code>\u4e5f\u4f1a\u4e0b\u964d\uff0c\u6700\u7ec8\u53d8\u4e3a0<\/p>\n<\/li>\n\nFss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fss<\/code>\u53d7\u5230V\u3001L\u3001\u83f2\u6d85\u5c14\u53cd\u5c04\u7387\u7684\u5171\u540c\u5f71\u54cd\uff0c\u5f53\u5f62\u6210\u63a0\u5c04\u65f6\uff0c\u503e\u5411\u4e8eFss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fss90^2<\/code>\uff1b\u5f53\u5f62\u6210\u5782\u76f4\u5165\u5c04\u65f6\uff0c\u503e\u5411\u4e8e\u5e38\u65701<\/p>\n<\/li>\n<\/ul>\nFrensel<\/h2>\nDisney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Disney\u4ea6\u91c7\u7528\u4e86\u4e1a\u754c\u5e38\u7528\u7684\u65b9\u6848\u2014\u2014Schlick Fresnel\u8fd1\u4f3c\u3002\u4e3b\u8981\u56e0\u4e3a\u8ba1\u7b97\u6210\u672c\u4f4e\uff0c\u4e14\u7cbe\u5ea6\u8db3\u591f\n<\/p >\n<\/p><\/noscript>\n\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u4e0d\u540c\u7684\u662f\uff0cDisney\u4e0d\u4f1a\u523b\u610f\u5f15\u5165F0\uff0c\u800c\u662f\u901a\u8fc7metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
metallic\u5bf9specularTint\u3001albedo\u63d2\u503c<\/code>\u8ba1\u7b97\u5f97\u5230F0<\/p>\n\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\/\/ u\uff1adot(V, N)\n\/\/ \u8fd4\u56de\u503c\uff1aF0\u4e3a0\u65f6\u7684SchlickFresnel\n\/\/ \u5728\u5916\u90e8\u8fdb\u884c\u63d2\u503c\nfloat SchlickFresnel(float u)\n{\n float m = clamp(1-u, 0, 1); \/\/\u5c061-vdoth\u7684\u7ed3\u679c\u9650\u5236\u5728[0,1]\u7a7a\u95f4\u5185 \n float m2 = m*m;\n return m2*m2*m; \/\/ pow(m,5) \u6c425\u6b21\u65b9\n}\n<\/code><\/pre>\nNDF<\/h2>\n\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\nTrowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5728NDF\u4e0a\uff0cDisney\u9009\u62e9\u4e86\u6709\u7740\u6700\u957f\u62d6\u5c3e\u7684GGX\u5206\u5e03\uff0c\u4e14Disney\u53d1\u73b0Trowbridge-Reitz\u548cBerry\u5177\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\u3002\u9488\u5bf9\u6b64\u73b0\u8c61\u7684NDF\u51fd\u6570\u505a\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGeneralized-Trowbridge-Reitz\uff0cGTR<\/p>\n
Trowbridge-Reitz\uff1a<\/p>\n
<\/p >\n<\/p><\/noscript>\nBerry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Berry\uff1a\u6307\u6570\u4e3a1\u800c\u4e0d\u662f2\uff0c\u4ece\u800c\u5bfc\u81f4\u66f4\u957f\u7684\u5c3e\u90e8<\/p>\n
<\/p >\n<\/p><\/noscript>\nGeneralized-Trowbridge-Reitz\uff1a<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Generalized-Trowbridge-Reitz\uff1a<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u03b3\uff1a\u7528\u4e8e\u63a7\u5236\u5c3e\u90e8\u5f62\u72b6\uff0c\u03b3\u8d8a\u5927\uff0c\u5206\u5e03\u7ea6\u96c6\u4e2d\uff0c\u5c3e\u90e8\u7ea6\u5c0f<\/li>\nc\uff1a\u7f29\u653e\u56e0\u5b50<\/li>\n<\/ul>\n\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n\n\u4e3b\u6ce2\u74e3\uff08primary lobe\uff09\n\n\u4f7f\u7528\u03b3= 2\u7684GTR\uff08\u5373GGX\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u5e95\u5c42\u6750\u8d28\uff08Base Material\uff09<\/li>\n\u53ef\u4e3a\u5404\u9879\u5f02\u6027\uff08anisotropic\uff09 \u6216\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u91d1\u5c5e\u6216\u975e\u91d1\u5c5e<\/li>\n<\/ul>\n<\/li>\n\u6b21\u7ea7\u6ce2\u74e3\uff08secondary lobe\uff09\n\n\u4f7f\u7528\u03b3= 1\u7684GTR\uff08\u5373Berry\u5206\u5e03\uff09<\/li>\n\u4ee3\u8868\u57fa\u7840\u6750\u8d28\u4e0a\u7684\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n\u4e00\u822c\u4e3a\u5404\u9879\u540c\u6027\uff08isotropic\uff09\u7684\u975e\u91d1\u5c5e\u6750\u8d28\uff0c\u5373\u6e05\u6f06\u5c42\uff08ClearCoat Layer\uff09<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u53e6\u5916\uff0cDisney\u4f7f\u7528\u4e24\u4e2a\u56fa\u5b9a\u7684\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\uff08specular lobe\uff09\uff0c\u4e14\u90fd\u4f7f\u7528GTR\u6a21\u578b\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n
\/\/ Disney\u53d1\u73b0GGX \u548c Berry\u6709\u76f8\u4f3c\u7684\u5f62\u5f0f\uff0c\u53ea\u662f\u5e42\u6b21\u4e0d\u540c\uff0c\u4e8e\u662f\uff0cDisney\u5c06Trowbridge-Reitz\u8fdb\u884c\u4e86N\u6b21\u5e42\u7684\u63a8\u5e7f\uff0c\u5e76\u5c06\u5176\u53d6\u540d\u4e3aGTR\n\/\/ \u57fa\u672c\u5f62\u5f0f\u662f\uff1ac\/pow((a^2*cos(NdotH)^2 + sin(NdotH)^2),b) . c\u4e3a\u653e\u7f29\u5e38\u6570\uff0ca\u4e3a\u7c97\u7cd9\u5ea6\n\/\/ Disney\u7684BRDF\u4f7f\u7528\u4e24\u4e2aspecular lobe\n\/\/ b=1\u4e3a\u6b21\u7ea7\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u6e05\u6f06\u5c42\n\/\/ b=2\u4e3a\u4e3b\u6ce2\u74e3\uff0c\u7528\u6765\u8868\u8fbe\u57fa\u7840\u6750\u8d28\nfloat D_GTR1(float NoH, float roughness)\n{\n \/\/\u8003\u8651\u5230\u7c97\u7cd9\u5ea6a\u5728\u7b49\u4e8e1\u7684\u60c5\u51b5\u4e0b\uff0c\u516c\u5f0f\u8fd4\u56de\u503c\u65e0\u610f\u4e49\uff0c\u56e0\u6b64\u56fa\u5b9a\u8fd4\u56de1\/pi\uff0c\n \/\/\u8bf4\u660e\u5728\u5b8c\u5168\u7c97\u7cd9\u7684\u60c5\u51b5\u4e0b\uff0c\u5404\u4e2a\u65b9\u5411\u7684\u6cd5\u7ebf\u5206\u5e03\u5747\u5300\uff0c\u4e14\u79ef\u5206\u540e\u5f971\n if (roughness >= 1) return 1\/PI;\n\n float a2 = roughness * roughness;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return (a2 - 1.0) \/ (PI * log(a2) * den);\n}\n\nfloat D_GTR2(float roughness2, float NoH)\n{\n float a2 = roughness2 * roughness2;\n float cos2th = NoH * NoH;\n float den = (1.0 + (a2 - 1.0) * cos2th);\n\n return a2 \/ (PI * den * den);\n}\n<\/code><\/pre>\n\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5404\u9879\u5f02\u6027\u7248\u672c\u5165\u53c2\u8f83\u4e3a\u590d\u6742\uff0c\u5728\u4f7f\u7528\u524d\u4f1a\u5bf9ax\u548cay\u505a\u9884\u5904\u7406\uff0c\u5f15\u5165anisotrpic\u548croughness<\/p>\n
\/\/\u4e3b\u6ce2\u74e3 \u5404\u9879\u5f02\u6027\n\/\/ VoX\uff1aDot(H, \u7269\u4f53\u8868\u9762\u7684\u5207\u7ebf\u5411\u91cf)\n\/\/ HdotY\uff1a\u4e3a\u534a\u89d2\u70b9\u4e58\u5207\u7ebf\u7a7a\u95f4\u4e2d\u7684\u526f\u5207\u7ebf\u5411\u91cf \n\/\/ ax \u548c ay \u5206\u522b\u662fx\u3001y2\u4e2a\u65b9\u5411\u4e0a\u7684\u53ef\u611f\u7c97\u7cd9\u5ea6\uff0c\u8303\u56f4\u662f0~1\nfloat GTR2_aniso(float NoH, float HoX, float HoY, float ax, float ay)\n{\n return rcp(PI * ax*ay * Pow2( Pow2(HoX \/ ax) + Pow2(HoY \/ ay) + Pow2(NoH) ));\n}\n<\/code><\/pre>\n\nroughness\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\nanisotropic\u4e0e\u66f2\u7ebf\u659c\u7387\u589e\u957f\u5e45\u5ea6\u6210\u6b63\u76f8\u5173<\/li>\n<\/ul>\nGeometry<\/h2>\n\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u91cd\u65b0\u9002\u914d\u53c2\u6570\uff0c\u4e0eNDF GTR\u914d\u5408\u4f7f\u7528\u3002\u8be5G\u9879\u672c\u8d28\u662f\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u51fd\u6570\uff0c\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u9700\u8981\u72ec\u7acb\u8ba1\u7b97\u906e\u853d\u548c\u9634\u5f71\u90e8\u5206<\/code>\uff0c\u6700\u540e\u7528\u4e58\u6cd5\u7edf\u4e00\u8d77\u6765\u3002\u8be5\u6a21\u578b\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5b8c\u5168\u4e0d\u8003\u8651\u590d\u6742\u7684\u591a\u6b21\u53cd\u5c04\u5149\u8def<\/code>\uff0c\u53ea\u628a\u5149\u7ebf\u5206\u4e3a\u5728\u5165\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u906e\u853dG(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
G(l)<\/code>\uff09\u548c \u5728\u51fa\u5c04\u65b9\u9762\u7684\u635f\u5931\uff08\u9634\u5f71G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
G(v)<\/code>\uff09\uff0c\u4e14\u4e3a\u4e00\u6b21\u6027\u7684<\/p>\n<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5728\u4e00\u5f00\u59cb\uff0c\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\uff08primary specular lobe\uff09\uff0cDisney\u53c2\u8003\u4e86 Walter\u7684\u8fd1\u4f3c\u65b9\u6cd5\uff0c\u4f7f\u7528Smith GGX\u5bfc\u51fa\u7684G\u9879\uff0c\u5e76\u5c06\u7c97\u7cd9\u5ea6\u53c2\u6570\u8fdb\u884c\u91cd\u6620\u5c04\u4ee5\u51cf\u5c11\u5149\u6cfd\u8868\u9762\u7684\u6781\u7aef\u589e\u76ca\uff0c\u5373\u5c06\u03b1 \u4ece[0, 1]\u91cd\u6620\u5c04\u5230[0.5, 1]\uff0c\u03b1\u7684\u503c\u4e3a(0.5 + roughness\/2)^2\u3002\u4ece\u800c\u4f7f\u51e0\u4f55\u9879\u7684\u7c97\u7cd9\u5ea6\u53d8\u5316\u66f4\u52a0\u5e73\u6ed1\uff0c\u66f4\u4fbf\u4e8e\u7f8e\u672f\u4eba\u5458\u7684\u4f7f\u7528<\/p>\n
\u4f46\u540e\u6765\u5728SIGGRAPH 2015\u4e0a\uff0c\u5bf9G\u9879\u8fdb\u884c\u4e86\u4fee\u8ba2\uff0c\u4ed6\u4eec\u57fa\u4e8eHeitz\u7684\u5206\u6790[Heitz 2014]\uff0c\u6dd8\u6c70\u4e86\u5bf9\u4e8e\u4e3b\u955c\u9762\u6ce2\u74e3\u7684Smith G\u7c97\u7cd9\u5ea6\u7684\u7279\u6b8a\u91cd\u6620\u5c04\uff0c\u91c7\u7528\u4e86Heitz\u5404\u5411\u5f02\u6027\u7684G<\/p>\n
\/\/ \u6e05\u6f06\u5c42 \u6b21\u7ea7\u6ce2\u74e3\n\/\/ 2012\u7248disney,\u672c\u8d28\u662fSmith\u8054\u5408\u906e\u853d\u9634\u5f71\u51fd\u6570\u4e2d\u7684\u201c\u5206\u79bb\u7684\u906e\u853d\u9634\u5f71\u578b\u201d\n\/\/ NoV\u89c6\u60c5\u51b5\u4e5f\u53ef\u66ff\u6362\u4e3aNdotL\uff0c\u7528\u4e8e\u8ba1\u7b97\u9634\u5f71\u76f8\u5173\u7684G1\n\/\/ alphag\u88abdisney\u5b9a\u4e49\u4e3a0.25f\nfloat G_GGX(float NoV, float alphag)\n{\n float a = alphag * alphag;\n float b = NoV * NoV;\n return 1.0 \/ (NoV + sqrt(a + b - a * b));\n}\n\n\/\/ \u5404\u5411\u5f02\u6027 \u4e3b\u6ce2\u74e3\nfloat smithG_GGX_aniso(float NoV, float VoX, float VoY, float ax, float ay)\n{\n return 1 \/ (NoV + sqrt( Pow2(VoX*ax) + Pow2(VoY*ay) + Pow2(NoV) ));\n}\n<\/code><\/pre>\n\n\u5404\u9879\u540c\u6027\u548c\u5404\u9879\u5f02\u6027\u7684\u7248\u672c\uff0c\u5728\u5404\u4e2a\u89d2\u5ea6\u4fdd\u6301\u4e86\u6052\u5b9a\u7684\u8f93\u51fa\uff0c\u4f46\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u9aa4\u7136\u63d0\u5347\uff08\u964d\u4f4e\u906e\u853d\u80fd\u529b\uff09<\/li>\n\u5404\u9879\u540c\u6027\u7248\u672c\u7684G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
G<\/code>\u9879\u4f7f\u7528\u56fa\u5b9a\u7684a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
a<\/code>\uff0c\u4e3a0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
0.25<\/code>\uff0c\u7528\u4e8e\u6e05\u6f06\u5c42\u9ad8\u5149\u6e32\u67d3<\/li>\n\u589e\u52a0\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u7c97\u7cd9\u5ea6<\/code>\u548c\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5404\u9879\u5f02\u6027\u5ea6<\/code>\u90fd\u4f1a\u8ba9\u66f2\u7ebf\u659c\u7387\u53d8\u5f97\u5e73\u7f13\u2014\u2014\u8d8a\u662f\u7c97\u7cd9\u7684\u8868\u9762\uff0c\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\u906e\u853d\u80fd\u529b\u8d8a\u5f3a<\/li>\n<\/ul>\n\u53c2\u6570\u89e3\u8bfb<\/h1>\nBaseColor<\/h2>\n\n\u91d1\u5c5e\uff1a\u53cd\u5c04\u7387<\/li>\n\u975e\u91d1\u5c5e\uff1a\u6f2b\u53cd\u5c04\u989c\u8272<\/li>\n<\/ul>\nSubsurface<\/h2>\n\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u8fd1\u4f3c\u63a7\u5236\u6f2b\u53cd\u5c04\u5f62\u72b6<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u63a7\u5236\u6f2b\u53cd\u5c04\u5149\u6e17\u5165\u7269\u4f53\u8fb9\u7f18\u7684\u5f3a\u5ea6<\/li>\n\u5927\u5e45\u63d0\u9ad8\u9006\u53cd\u5c04\u89d2\u7684\u4eae\u5ea6<\/li>\n<\/ul>\nmetallic<\/h2>\n\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u5f53metallic\u8d8b\u54111\u65f6\uff0c\u5f31\u5316\u6f2b\u53cd\u5c04\u7387\uff0c\u5f3a\u5316\u955c\u9762\u53cd\u5c04\u5f3a\u5ea6\uff0c\u540c\u65f6\u955c\u9762\u53cd\u5c04\u9010\u6e10\u9644\u5e26\u4e0a\u91d1\u5c5e\u8272<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u7eaf\u91d1\u5c5e\u6750\u8d28\u51e0\u4e4e\u4e0d\u5f62\u6210\u6f2b\u53cd\u5c04\uff0c\u5f71\u54cd\u5149\u7167\u5f3a\u5ea6\u7684\u53ea\u6709\u9ad8\u5149\u548c\u6e05\u6f06\u6ce2\u74e3<\/li>\n\u9ad8\u5149\u5e26\uff08specular peak\uff09\u4f53\u73b0\u51fa\u5f3a\u70c8\u7684\u91d1\u5c5e\u8272\uff0c\u800c\u975e\u91d1\u5c5e\u800c\u6ca1\u6709<\/li>\n<\/ul>\nspecular<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5149\u5360\u5165\u5c04\u5149\u7684\u6bd4\u7387<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u7684\u53cd\u5c04\u7387\u53d6\u51b3\u4e8ebaseColor\uff0c\u8be5\u9879\u5bf9\u7eaf\u91d1\u5c5e\u4e0d\u751f\u6548<\/li>\n\u5bf9\u975e\u91d1\u5c5e\u800c\u8a00\uff0c\u8be5\u9879\u63a7\u5236\u955c\u9762\u53cd\u5c04\u6bd4\u7387\uff0c\u5f71\u54cd\u83f2\u5c3c\u5c14\u9879Fs<\/li>\n<\/ul>\nspecularTint<\/h2>\n\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u548cbaseColor\u4e00\u8d77\u63a7\u5236\u955c\u9762\u53cd\u5c04\u7684\u989c\u8272<\/p>\n
<\/p >\n<\/p><\/noscript>\nroughness<\/h2>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cddiffuse\u548cspecular<\/p>\n<\/li>\n\n\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u4ece\u5b8c\u5168\u5149\u6ed1\u5230\u5b8c\u5168\u7c97\u7cd9\uff0c\u9ad8\u5149\u5e26\u7684\u80fd\u91cf\u4ece\u805a\u96c6\u5728\u4e00\u70b9\uff0c\u5230\u5206\u6563\uff08\u80fd\u91cf\u5b88\u6052\uff09\uff0c\u6700\u540e\u9ad8\u5149\u5e26\u6d88\u5931\uff08Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Gs<\/code>\u548cDs<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Ds<\/code>\u7684\u5171\u540c\u5f71\u54cd\uff09<\/p>\n<\/li>\n<\/ul>\nanisotropic<\/h2>\n\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u63a7\u5236\u955c\u9762\u53cd\u5c04\u5728\u4e0d\u540c\u671d\u5411\u4e0a\u7684\u5f3a\u5ea6\u2014\u2014\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u955c\u9762\u53cd\u5c04\u9ad8\u5149\u7684\u7eb5\u6a2a\u6bd4<\/code><\/p>\n<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/p >\n<\/p><\/noscript>\nsheen<\/h2>\n\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u989d\u5916\u7684\u6f2b\u53cd\u5c04\u63a0\u5c04\u5206\u91cf\uff08\u8fb9\u7f18\u6f2b\u53cd\u5c04\u7684\u8865\u507f\uff09\uff0c\u4e3b\u8981\u7528\u4e8e\u5e03\u6599\u3002\u5728\u63a0\u5c04\u89d2\u9644\u8fd1\uff0c\u4e14\u5fae\u8868\u9762\u6cd5\u7ebf\u4e0e\u5b8f\u89c2\u5939\u89d2\u63a5\u8fd190\u5ea6\u65f6\uff0c\u5f15\u5165\u989d\u5916\u7684\u5149\u91cf\u4ee5\u8d77\u5230\u63d0\u4eae\u6548\u679c<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u91d1\u5c5e\u6ca1\u6709sheen<\/li>\n\u4e13\u95e8\u63a7\u5236\u7269\u4f53\u8f6e\u5ed3\/\u8fb9\u7f18\u7684\u6f2b\u53cd\u5c04\u5f3a\u5ea6<\/li>\nsheen\u503c\u589e\u52a0\u4e3b\u8981\u5f71\u54cdFresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Fresnel Peak\u7684\u5f62\u72b6<\/code>\uff0c\u5728\u63a0\u5c04\u60c5\u51b5\u4e0b\uff0c\u589e\u5f3a\u89c6\u89d2\u4e24\u4fa7\u8fb9\u7f18\u7684\u5149\u80fd\u7684\u6e17\u900f<\/li>\n<\/ul>\nsheenTint<\/h2>\n\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u63a7\u5236sheen\u7684\u989c\u8272<\/p>\n
<\/p >\n<\/p><\/noscript>\n\nTint\u57fa\u4e8ebase color<\/li>\n<\/ul>\nclearcoat<\/h2>\n\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u63a7\u5236\u7b2c\u4e8c\u4e2a\u955c\u9762\u53cd\u5c04\u6ce2\u74e3\u7684\u5f62\u6210\u53ca\u5f71\u54cd\u8303\u56f4<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u6709\u81ea\u5df1\u7684G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
G<\/code>,F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
F<\/code>\u548cD<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
D<\/code>\u51fd\u6570\uff08\u5404\u9879\u540c\u6027\uff09<\/li>\n\u63a7\u5236\u53cd\u5c04\u5149\u6591\u7684\u5927\u5c0f<\/li>\n\u5728\u5e95\u5c42\u955c\u9762\u53cd\u5c04\u6bd4\u8f83\u6697\u6de1\u6a21\u7cca\u65f6\u6bd4\u8f83\u660e\u663e<\/li>\n<\/ul>\nclearcoatGloss<\/h2>\n\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u63a7\u5236\u900f\u660e\u6d82\u5c42\u7684\u9ad8\u5149\u5f3a\u5ea6<\/p>\n
<\/p >\n<\/p><\/noscript>\n\n\u5f71\u54cd\u6e05\u6f06\u5c42BRDF\u51fd\u6570\u4e2d\u7684\u6cd5\u7ebf\u5206\u5e03\u9879Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Dr<\/code><\/li>\n<\/ul>\n\u4ee3\u7801\u4ed3\u5e93<\/h1>\nhttps:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\nReference<\/h1>\n\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
https:\/\/github.com\/chenglixue\/Unity-Disney-BRDF-with-GI<\/p>\n
\u57fa\u4e8e\u7269\u7406\u7684\u6e32\u67d3\uff08PBR\uff09\u767d\u76ae\u4e66 | \u8fea\u58eb\u5c3c\u539f\u5219\u7684BRDF\u4e0eBSDF\u76f8\u5173\u603b\u7ed3<\/a><\/p>\nDisney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Disney Principled BRDF\u5b9e\u73b0\u7b14\u8bb0<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u4ec0\u4e48\u662fBRDF & PBR? \u6e32\u67d3\u5176\u5b9e\u662f\u5728\u8ba1\u7b97\u753b\u9762\u7684\u5149\u7167\u548c\u9634\u5f71\uff0c\u800cBRDF\u5728\u6e32\u67d3\u4e2d\u8d77\u7740\u4e3e\u8db3\u8f7b\u91cd\u7684\u4f5c\u7528\u3002\u5b83\u4f1a\u8ba1\u7b97\u5f53\u5149\u7ebf\u7269\u4f53\u63a5 …<\/p>","protected":false},"author":1,"featured_media":179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178"}],"collection":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=178"}],"version-history":[{"count":2,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions"}],"predecessor-version":[{"id":248,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/178\/revisions\/248"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/179"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=178"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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