{"id":300,"date":"2024-11-13T00:04:06","date_gmt":"2024-11-12T16:04:06","guid":{"rendered":"http:\/\/chenglixue.top\/?p=300"},"modified":"2024-11-13T00:04:06","modified_gmt":"2024-11-12T16:04:06","slug":"%e6%9b%b4%e5%a5%bd%e7%9a%84%e6%ac%a1%e8%a1%a8%e9%9d%a2%e6%b8%b2%e6%9f%93-separable-subsurface-scatter","status":"publish","type":"post","link":"http:\/\/chenglixue.top\/?p=300","title":{"rendered":"\u66f4\u597d\u7684\u6b21\u8868\u9762\u6e32\u67d3 Separable Subsurface Scatter"},"content":{"rendered":"<p><div class=\"has-toc have-toc\"><\/div><\/p>\n<h1>\u524d\u8a00<\/h1>\n<p>\u524d\u6587\u63d0\u5230\u4e86\u5982\u4f55\u5b9e\u73b0\u9002\u5408\u4e8e\u79fb\u52a8\u7aef\u7684\u9884\u79ef\u5206\u6b21\u8868\u9762\u6563\u5c04\u6548\u679c\uff0c\u4f46\u8fd9\u79cd\u6548\u679c\u5e76\u4e0d\u662f\u7279\u522b\u597d\uff0c\u5bf9\u4e8ePC\u7aef\u8fd8\u6709\u5176\u4ed6\u6548\u679c\u66f4\u597d\u7684\u5b9e\u65f6\u6e32\u67d3\u65b9\u6848\uff0c\u4e14\u4e24\u5927\u7684\u5f15\u64ceUnity\u3001UE\u90fd\u7528\u5230\u4e86\u6b64\u65b9\u6848\u2014\u2014\u5373Screen Space Subsurface Scattering(SSSSS, 5S)\u3002\u4f46\u5149\u662f5S\u9700\u8981\u6d88\u8017\u4e0d\u5c11\u6027\u80fd\uff0c\u57fa\u4e8e\u6b64\u57fa\u7840\u4e0a\uff0c\u4e24\u5927\u5f15\u64ce\u53c8\u505a\u4e86\u4f18\u5316\uff0c\u4f7f\u7528\u9ad8\u65af\u6df7\u5408\u6a21\u578b\uff0c\u4ee5\u53ca\u9ad8\u65af\u6838\u53ef\u5206\u79bb\u6027\uff0c\u8ba9 SSS \u53ef\u4ee5\u4ee5\u6bd4\u8f83\u4f4e\u7684\u4ee3\u4ef7\u5b9e\u65f6\u7684\u8fd0\u884c\u8d77\u6765\u2014\u2014\u5373Separable Subsurface Scattering)(4S)<\/p>\n<h1>UE\u7684\u65b9\u6848<\/h1>\n<p>UE\u5bf9\u76ae\u80a4\u3001\u7389\u77f3\u7b49\u5177\u6709\u6b21\u8868\u9762\u6563\u5c04\u6548\u5e94\u7684\u7269\u4f53\u63d0\u4f9b\u4e86\u4e09\u79cd\u6e32\u67d3\u65b9\u6848\uff1a<\/p>\n<ul>\n<li>Subsurface<\/li>\n<li>Preintegrated Skin<\/li>\n<li>Subsurface Profile<\/li>\n<\/ul>\n<p>\u4e09\u8005\u6027\u80fd\u6d88\u8017\u9010\u6e10\u9012\u589e\u3002\u5176\u4e2d\uff0cPreintegrated Skin\u5728\u524d\u6587\u5df2\u7ecf\u4ecb\u7ecd\u8fc7\u3002\u800c4s\u76f8\u5bf9\u4f20\u7edf3s\u4e3b\u8981\u533a\u522b\u5728\u4e8e\uff1a<\/p>\n<ul>\n<li>\u9002\u7528\u4e8e\u5ef6\u8fdf\u6e32\u67d3\uff0c\u5426\u5219\u8bb8\u591a\u53c2\u6570\u83b7\u53d6\u5341\u5206\u9ebb\u70e6<\/li>\n<li>\u57fa\u4e8e\u5c4f\u5e55\u7a7a\u95f4<\/li>\n<li>\u8981\u6c42\u8f93\u5165\u5206\u79bb\u7684Diffuse\u548cSpecular<\/li>\n<li>\u7b97\u6cd5\u6838\u5fc3\u7684\u5377\u79ef\uff08\u6ee4\u6ce2\uff09\u8fd0\u7b97\uff0c\u5de5\u4f5c\u5728\u540e\u5904\u7406\u4e4b\u540e\uff0ctonemapping\u4e4b\u524d<\/li>\n<\/ul>\n<h1>\u6b21\u8868\u9762\u6563\u5c04\u7b97\u6cd5<\/h1>\n<p>\u5173\u4e8e\u6b21\u8868\u9762\u6563\u5c04\u7684\u6210\u56e0\u53ca\u76ae\u80a4\u7ec4\u7ec7\u5efa\u6a21\u5728\u4e0a\u7bc7\u5df2\u7ecf\u63d0\u8fc7\uff0c\u8fd9\u91cc\u4e0d\u518d\u63d0\u53ca<\/p>\n<h2>\u9ad8\u5149<\/h2>\n<p>\u9ad8\u5149\u90e8\u5206\u4f9d\u65e7\u91c7\u7528Cook-Torrance\u7684BRDF\uff0c\u5bf9\u5e94\u516c\u5f0f\u5982\u4e0b\uff1a<br \/>\n<img decoding=\"async\"  src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a515364832.png\" alt=\"1730826563562.png\" \/><img decoding=\"async\"  class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a51536ce64.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730826569403.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a515364832.png\" alt=\"1730826563562.png\" \/><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a51536ce64.png\" alt=\"1730826569403.png\" \/><\/p><\/noscript>\n<h2>\u6f2b\u53cd\u5c04<\/h2>\n<h3>BSSRDF<\/h3>\n<p>\u6f2b\u53cd\u5c04\u90e8\u5206\u4f7f\u7528\u5230\u7684\u662fBSSRDF\uff0c\u76f8\u8f83\u4e8eBRDF\uff0cBSSRDF<strong>\u6bcf\u4e00\u6b21\u53cd\u5c04\u5728\u7269\u4f53\u8868\u9762\u4e0a\u6bcf\u4e00\u4e2a\u4f4d\u7f6e\u90fd\u8981\u505a\u4e00\u6b21\u534a\u7403\u9762\u79ef\u5206<\/strong>\uff0c\u662f\u4e00\u4e2a\u5d4c\u5957\u79ef\u5206\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a526a9ab1a.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730826849757.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a526a9ab1a.png\" alt=\"1730826849757.png\" \/><\/p><\/noscript>\n<p>\u5b83\u7684\u542b\u4e49\u662f\uff1a<strong>\u5f53\u4e00\u675f\u5149\u4ee5\u4efb\u610f\u89d2\u5ea6\u5165\u5c04\u5230\u67d0\u4e2a\u786e\u5b9a\u7684\u5fae\u8868\u9762p\u4e0a\u65f6\uff0c\u6709\u591a\u5c11Radiance\u80fd\u591f\u4ece\u4efb\u610f\u4e00\u4e2a\u7ed9\u5b9a\u7684\u5fae\u8868\u9762q\u4e0a\u4ee5\u67d0\u4e2a\u7ed9\u5b9a\u7684\u51fa\u5c04\u89d2\u5ea6\u53cd\u5c04\u51fa\u53bb<\/strong><\/p>\n<p>\u5bf9BSSRDF\u6e32\u67d3\u65b9\u7a0b\u7684\u89e3\u6790\u5728\u4e0a\u7bc7\u4e5f\u6709\u63d0\u53ca\uff0c\u8fd9\u91cc\u4e0d\u518d\u89e3\u91ca<\/p>\n<p>\u5bf9\u4e8eBSSRDF\u6e32\u67d3\u65b9\u7a0b\u7684S\u51fd\u6570\u90e8\u5206\u53ef\u4ee5\u7b3c\u7edf\u7684\u5f52\u7eb3\u4e3a\u4ee5\u4e0b\u5f62\u5f0f\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a540c07aba.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730827265434.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a540c07aba.png\" alt=\"1730827265434.png\" \/><\/p><\/noscript>\n<p>\u8868\u793a\u4ee5<span class=\"katex math inline\">\u03c9_i<\/span>\u89d2\u5ea6\u5411<span class=\"katex math inline\">x_i<\/span>\u4f4d\u7f6e\u5165\u5c04\u7684radiance\uff0c\u5728<span class=\"katex math inline\">x_o<\/span>\u5904\u4ee5<span class=\"katex math inline\">\u03c9_o<\/span>\u89d2\u5ea6\u51fa\u5c04\u7684irradiance\u4e3a\u591a\u5c11\u3002\u8fd9\u90e8\u5206\u770b\u4f3c\u6bd4\u8f83\u7b80\u5355\uff0c\u4f46\u662f\u5b83\u662f\u6b21\u8868\u9762\u6563\u5c04\u4e2d\u6700\u4e3a\u91cd\u8981\u7684\u4e00\u90e8\u5206\uff0c\u4e5f\u662f\u6700\u590d\u6742\u7684\u4e00\u90e8\u5206<\/p>\n<p>\u5bf9\u4e8eS\u51fd\u6570\uff0c\u6709\u5982\u4e0b\u7ecf\u9a8c\u516c\u5f0f\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a55610e29e.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730827607735.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a55610e29e.png\" alt=\"1730827607735.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">F_t<\/span>\uff1aFresnel\u900f\u5c04\u6548\u5e94\uff0c\u7528\u4e8e\u6a21\u62df\u5165\u5c04\u548c\u51fa\u5c04\u8fc7\u7a0b\u7684\u6d88\u8017\uff0c\u4e00\u822c\u53ea\u548c<strong>\u6750\u8d28\u5c5e\u6027\u548c\u89d2\u5ea6<\/strong>\u6709\u5173<\/li>\n<li>\u200b    <span class=\"katex math inline\">R_d(|p_i - p_o|)<\/span>\uff1a\u6563\u5c04\u51fd\u6570\uff0c\u4e3b\u8981\u4e0e\u5165\u5c04\u70b9\u548c\u51fa\u5c04\u70b9\u7684\u8ddd\u79bb\u6709\u5173\u3002\u5b83\u7684\u771f\u8eab\u5982\u4e0b\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5661252cd.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730827864072.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5661252cd.png\" alt=\"1730827864072.png\" \/><\/p><\/noscript>\n<ul>\n<li>D\uff1a\u6f2b\u53cd\u5c04\u5e38\u91cf<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a568a669de.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730827905604.png\" \/><\/li >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a568a669de.png\" alt=\"1730827905604.png\" \/><\/li><\/noscript>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u53ef\u4ee5\u770b\u5230BSSRDF\u6e32\u67d3\u65b9\u7a0b\u662f\u5341\u5206\u590d\u6742\u7684\uff0c\u60f3\u7528\u6b64\u505a\u5230\u5b9e\u65f6\u662f\u4e0d\u53ef\u80fd\u7684\u3002\u867d\u7136\u5b8c\u5168\u7269\u7406\u7684\u505a\u4e0d\u5230\uff0c\u4f46\u53ef\u4ee5\u7528\u8fd1\u4f3c\u6cd5\u6765\u903c\u8fd1\u4ee5\u964d\u4f4e\u6d88\u8017<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a572e1120c.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730828048463.png\" \/><br \/ >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a572e1120c.png\" alt=\"1730828048463.png\" \/><br \/><\/noscript>\n\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">F_r(cos_{\u03b8_o})<\/span>\uff1aFresnel\u53cd\u5c04\u9879<\/p>\n<\/li>\n<li>\n<p>\u200b    <span class=\"katex math inline\">S_p(p_o, p_i)<\/span>\uff1a\u70b9p\u5904\u7684\u6563\u5c04\u51fd\u6570\u3002\u53ef\u4ee5\u8fdb\u4e00\u6b65\u8868\u793a\u4e3a<span class=\"katex math inline\">S_r(|p_0 - p_i|)<\/span><\/p>\n<p>\u200b \u800c<span class=\"katex math inline\">S_r<\/span>\u4e0e\u4ecb\u8d28\u7684\u8bb8\u591a\u5c5e\u6027\u76f8\u5173\uff0c\u53ef\u7528\u516c\u5f0f\u7b80\u5316\u5e76\u8868\u8fbe\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5e711ea62.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730829928116.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5e711ea62.png\" alt=\"1730829928116.png\" \/><\/p><\/noscript>\n<p>\u7b80\u5316\u540e\u7684Sr\u53ea\u8ddf\u03c1\u548cr\u6709\u5173\uff0c\u6bcf\u79cd\u6750\u6599\u7684\u03c1\u548cr\u53ef\u7ec4\u6210\u4e00\u4e2aBSSRDF\u8868\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5eac73c41.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730829987524.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5eac73c41.png\" alt=\"1730829987524.png\" \/><\/p><\/noscript>\n<\/li>\n<li>\n<p>\u200b    <span class=\"katex math inline\">S_\u03c9(\u03c9_i)<\/span>\uff1a\u542b\u6709\u7f29\u653e\u56e0\u5b50\u7684Fresnel\u9879\u3002\u516c\u5f0f\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5f4d1e5fd.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730830148420.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5f4d1e5fd.png\" alt=\"1730830148420.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2dc\u662f\u4e00\u4e2a\u5d4c\u5957\u7684\u534a\u7403\u9762\u79ef\u5206\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5f8f1f36c.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730830214729.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/06\/672a5f8f1f36c.png\" alt=\"1730830214729.png\" \/><\/p><\/noscript>\n<\/li>\n<\/ul>\n<h3>SeparableSSS<\/h3>\n<h4>Diffusion Profile<\/h4>\n<p>\u5b9e\u65f6\u6e32\u67d3\u4e2d\uff0c\u6b21\u8868\u9762\u6563\u5c04\u7684\u672c\u8d28\u662f\u5229\u7528\u9644\u8fd1pixel\u8fdb\u884c\u52a0\u6743\u5e73\u5747\uff0c\u5177\u6709\u4ee5\u4e0b\u7279\u70b9\uff1a<\/p>\n<ol>\n<li>\u5148\u5bf9\u6bcf\u4e2a\u50cf\u7d20\u8fdb\u884c\u5e38\u89c4\u7684\u6f2b\u53cd\u5c04\u8ba1\u7b97<\/li>\n<li>\u518d\u6839\u636e\u67d0\u79cd\u7279\u6b8a\u7684\u51fd\u6570<strong>Rd(r)<\/strong>\u548c\u4e0a\u8ff0\u6f2b\u53cd\u5c04\u7ed3\u679c\uff0c\u52a0\u6743\u8ba1\u7b97\u5468\u56f4\u82e5\u5e72\u4e2a\u50cf\u7d20\u5bf9\u5f53\u524d\u50cf\u7d20\u7684\u6b21\u8868\u9762\u6563\u5c04\u8d21\u732e<\/li>\n<\/ol>\n<p>\u53ef\u4ee5\u770b\u5230\uff0c\u6b21\u8868\u9762\u6563\u5c04\u548cBlur\u5f88\u50cf\uff0c\u90fd\u5229\u7528\u5377\u79ef\u6838\u8fdb\u884c\u52a0\u6743\u3002\u5176\u5b9e\uff0c\u8fd9\u91cc\u7684<strong>Rd(r)<\/strong>\u51fd\u6570\u548c\u5377\u79ef\u6838\u662f\u540c\u4e00\u6982\u5ff5\uff0c\u8be5\u51fd\u6570\u53ef\u4ee5\u7ed8\u5236\u5f97\u5230\u6240\u8c13\u7684<strong>\u6269\u6563\u5256\u9762<\/strong>\uff08Diffusion Profile\uff09\u3002\u5982\u4e0b\u56fe\u6240\u793a\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c849b3b6fc.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730970767283.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c849b3b6fc.png\" alt=\"1730970767283.png\" \/><\/p><\/noscript>\n<p>\u90a3<strong>Rd(r)<\/strong>\u51fd\u6570\u7a76\u7adf\u6709\u4f55\u7269\u7406\u542b\u4e49\u5462\uff1f\u5bf9\u4e8e\u4e00\u5757\u9762\u79ef\u65e0\u9650\uff0c\u4ecb\u8d28\u5747\u5300\uff0c\u539a\u5ea6\u65e0\u9650\u7684\u7406\u60f3\u8868\u9762\uff0c\u5f53\u4e00\u901f\u6fc0\u5149\u7167\u5c04\u4e0a\u53bb\u65f6\u4f1a\u5f15\u53d1\u5149\u7ebf\u5411\u5468\u56f4\u7684\u6269\u6563\uff0c\u5f62\u6210<strong>\u4ee5\u7167\u5c04\u70b9\u4e3a\u4e2d\u5fc3\u7684\u7a33\u5b9a\u5149\u6655<\/strong>\uff0c\u5efa\u6a21\u51fa\u6765\u53ef\u4ee5\u5f97\u5230\u4ee5\u4e0b\u7ed3\u679c\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c57050c8d2.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730959097090.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c57050c8d2.png\" alt=\"1730959097090.png\" \/><\/p><\/noscript>\n<p>\u6240\u8c13\u7684Diffusion Profile\uff0c\u5373\u4e0a\u56fe\u4e2d<strong>\u6295\u5f71\u5230x-z\u6216y-z\u5e73\u9762\u4e0a\u7684\u4e00\u5757\u6295\u5f71<\/strong>\u3002\u5b83\u53cd\u6620\u4e86<strong>\u6563\u5c04\u5149\u5f3a\u968f\u8ddd\u79bb\u7684\u5206\u5e03\u8d8b\u52bf<\/strong>\uff0c\u5b9e\u9a8c\u8868\u660e\u8fd9\u79cd\u8d8b\u52bf\u53ea\u53d7\u5230<strong>\u6750\u8d28\u5c5e\u6027<\/strong>\u3001<strong>\u6269\u6563\u8ddd\u79bb<\/strong>\u7684\u5f71\u54cd\uff0c<strong>\u4e0e\u5149\u7ebf\u7684\u5165\u5c04\/\u51fa\u5c04\u4f4d\u7f6e\u6216\u8005\u5149\u7ebf\u7684\u5165\u5c04\/\u51fa\u5c04\u65b9\u5411\u65e0\u5173<\/strong>\uff0c\u56e0\u800c\u662f<strong>\u5404\u5411\u540c\u6027<\/strong>\uff08<strong>isotropy<\/strong>\uff09\u7684\u5206\u5e03\u51fd\u6570<\/p>\n<h4>Separable Convolution<\/h4>\n<p>\u867d\u7136BSSRDF\u7528\u5230\u4e86\u8fd1\u4f3c\u903c\u8fd1\u6765\u4f18\u5316\u6027\u80fd\uff0c\u4f46\u5728\u540e\u7eed\u8fd8\u9700\u8fdb\u884c2D\u5377\u79ef\uff0c\u8ba1\u7b97\u91cf\u8fd8\u662f\u5f88\u5927\uff0c\u6709\u6ca1\u6709\u4ec0\u4e48\u529e\u6cd5\u5bf92D\u5377\u79ef\u8fdb\u884c\u4f18\u5316\u5462\uff1f\u8fd8\u771f\u6709\uff0c\u4e5f\u5c31\u662f\u672c\u6587\u7740\u91cd\u4ecb\u7ecd\u7684SeparableSSS<\/p>\n<p>SeparableSSS\u662fJimenez\u548cGutierrez\u57282015\u5e74\u7684\u8bba\u6587\u4e2d\u63d0\u51fa\u7684\uff0c\u4e3b\u8981\u8d21\u732e\u662f\u5c062D\u5377\u79ef\u62c6\u5206\u62102\u4e2a\u76f8\u5173\u76841D\u5377\u79ef\uff0c\u8be5\u65b9\u6cd5\u79f0\u4e3a\u5377\u79ef\u5206\u79bb\uff08Separable Convolution\uff09\u3002\u4e3b\u8981\u5f62\u5f0f\u5982\u4e0b\u56fe\u6240\u793a\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c60b1b3503.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730961574564.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c60b1b3503.png\" alt=\"1730961574564.png\" \/><\/p><\/noscript>\n<p>\u8bc1\u660e\u8fc7\u7a0b\u5982\u4e0b\u56fe\u6240\u793a\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c62850aebd.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730962041236.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c62850aebd.png\" alt=\"1730962041236.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">E<\/span>\uff1aradiance<\/li>\n<li>\u200b    <span class=\"katex math inline\">R_d<\/span>\uff1a\u6563\u5c04\u51fd\u6570<\/li>\n<li>\u200b    <span class=\"katex math inline\">x\u3001y<\/span>\uff1a\u51fa\u5c04\u70b9\u4f4d\u7f6e<\/li>\n<li>\u200b    <span class=\"katex math inline\">x'\u3001y'<\/span>\uff1a\u79ef\u5206\u53d8\u91cf<\/li>\n<li>\u200b    <span class=\"katex math inline\">dx'\u3001dy'<\/span>\uff1a<span class=\"katex math inline\">R^2<\/span>\u7684\u4e00\u5757\u5fae\u5143\u9762<\/li>\n<li>\u200b    <span class=\"katex math inline\">A<\/span>\uff1a\u5bf9<span class=\"katex math inline\">R_d<\/span>\u51fd\u6570\u7684\u8fd1\u4f3c<\/li>\n<li>\u200b    \u7b2c\u4e09\u884c\uff1a\u5c06<span class=\"katex math inline\">A<\/span>\u62c6\u5206\u4e3a\u591a\u4e2a\u4f4e\u7ef4\u51fd\u6570\uff0c\u5e76\u6c42\u548c<\/li>\n<li>\u200b    \u6700\u540e\u4e00\u884c\uff1a\u4e5f\u662f\u5173\u952e\u6240\u5728\uff0c<strong>\u56e0\u4e3a\u5377\u79ef\u6838a(x)\u3001a(y)\u6ca1\u6709\u5173\u8054\uff0c\u6240\u4ee5\u53ef\u4ee5\u5206\u5f00\u79ef\u5206<\/strong><\/li>\n<\/ul>\n<p>\u5176\u5b9e\uff0cSeparable Convolution\u5c31\u662f\u5728\u6a21\u7cca\u4e2d\u7ecf\u5e38\u7528\u5230\u7684\u9ad8\u65af\u6a21\u7cca\uff0c\u6c34\u5e73\u52a0\u6743\u4e00\u6b21\uff0c\u7ad6\u76f4\u518d\u52a0\u6743\u4e00\u6b21\u3002\u53ea\u662f\u5e76\u4e0d\u662f\u6240\u6709\u5377\u79ef\u6838\u90fd\u53ef\u4ee5Separable<\/p>\n<h4>$R_d$\u7684\u8fd1\u4f3c\u51fd\u6570A<\/h4>\n<p>\u4e3a\u4e86\u5f97\u5230\u8fd1\u4f3c\u51fd\u6570A\uff0c\u9700\u8981\u5148\u786e\u5b9a<span class=\"katex math inline\">R_d<\/span>\u51fd\u6570\u3002\u6570\u5b66\u4e0a\u5b9a\u4e49\u7684\u6563\u5c04\u51fd\u6570\u662f\u5341\u5206\u590d\u6742\u7684\uff0c\u5b83\u662f\u7531Jensen\u57282001\u5e74\u63d0\u51fa\u7684\u6563\u5c04\u6a21\u578b\uff0c\u5b58\u5728\u5927\u91cf\u7684\u516c\u5f0f\u63a8\u5bfc\uff0c\u8fd9\u91cc\u5c31\u7701\u53bb\u4e86\uff0c\u76f4\u63a5\u4e0b\u7ed3\u8bba\u3002\u5982\u4e0b\u56fe\u6240\u793a\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c678b32f6d.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730963326874.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c678b32f6d.png\" alt=\"1730963326874.png\" \/><\/p><\/noscript>\n<p>\u8fd9\u91cc\u63d0\u5230\u4e86\u5076\u6781\u5b50\uff08Dipole\uff09\u7684\u6982\u5ff5\uff0c\u6240\u8c13<strong>Dipole\u5373\u4e00\u5bf9\u4e92\u4e3a\u6b63\u8d1f\u7684\u70b9\u5149\u6e90<\/strong>\u3002\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    \u5c06<strong>\u6b63\u5149\u6e90<\/strong>\u653e\u4e8e\u8868\u76ae\u5c42\u7684\u4e0b\u65b9<span class=\"katex math inline\">Z_r<\/span>\u6df1\u5904\u3002\u7406\u60f3\u72b6\u6001\u4e0b\uff0c\u6b63\u5149\u6e90\u5411\u5916\u5747\u5300\u8f90\u5c04\u5149\u5f3a\uff0c\u540c\u65f6\u53d7\u5230\u4ecb\u8d28\u7684\u5f71\u54cd\uff0c\u8870\u51cf\u6563\u5c04<\/li>\n<li>\u200b    \u5c06<strong>\u8d1f\u5149\u6e90<\/strong>\u653e\u4e8e\u8868\u76ae\u5c42\u4e0e\u6b63\u5149\u6e90\u5bf9\u7acb\u7684\u4e00\u4fa7\uff0c\u9ad8\u5ea6\u4e3a<span class=\"katex math inline\">Z_v<\/span>\u3002\u8d1f\u5149\u6e90\u7528\u4e8e\u5438\u6536\u4ece\u8868\u9762\u6563\u5c04\u7684\u5149\u5f3a\uff0c\u4ee5\u8c03\u8282\u5f3a\u5ea6\u5206\u5e03<\/li>\n<\/ul>\n<p>\u8bf4\u4e86\u8fd9\u4e48\u591a\uff0c\u8fd8\u662f\u4e0d\u592a\u6e05\u695aDipole\u5230\u5e95\u662f\u4e2a\u5565\u4e1c\u897f\uff0c\u672c\u8d28\u4e0a\u8bb2<strong>Dipole\u8868\u793a\u7684\u662f\u76ae\u80a4\u8868\u9762x\u5904\u7684\u5149\u901a\u91cf<\/strong>\uff0c\u5b83\u53ef\u4ee5\u7528\u4ee5\u4e0b\u516c\u5f0f\u8868\u8fbe\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c69607b246.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730963797108.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c69607b246.png\" alt=\"1730963797108.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">D<\/span>\uff1a\u6563\u5c04\u5e38\u91cf<\/li>\n<li>\u200b    <span class=\"katex math inline\">\u03c3tr<\/span>\uff1a\u900f\u5c04\u5438\u6536\u56e0\u5b50<\/li>\n<li>\u200b    <span class=\"katex math inline\">d_r<\/span>\uff1a\u70b9x\u5230\u6b63\u5149\u6e90\u7684\u76f4\u7ebf\u8ddd\u79bb<\/li>\n<li>\u200b    <span class=\"katex math inline\">d_v<\/span>\uff1a\u70b9x\u5230\u8d1f\u5149\u6e90\u7684\u76f4\u7ebf\u8ddd\u79bb<\/li>\n<\/ul>\n<p>\u8fdb\u4e00\u6b65\u53ef\u4ee5\u5f97\u5230<span class=\"katex math inline\">R_d<\/span>\u51fd\u6570\u7684\u516c\u5f0f\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c6b2a9112c.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730964254484.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c6b2a9112c.png\" alt=\"1730964254484.png\" \/><\/p><\/noscript>\n<p>\u5bf9\u4e8e\u725b\u5976\u3001\u5927\u7406\u77f3\u8fd9\u7c7b\u6750\u8d28\uff0c\u4e00\u4e2aDipole\u8db3\u4ee5\u63cf\u8ff0\u6563\u5c04\u51fd\u6570\uff0c\u6d88\u8017\u8c8c\u4f3c\u4e0d\u5927\u3002\u4f46\u5bf9\u4e8e\u76ae\u80a4\u8fd9\u6837\u591a\u5c42\u7ed3\u6784\u7684\u6750\u8d28\uff0c\u9700\u8981\u4f7f\u75283\u4e2aDipole\u624d\u80fd\u8fbe\u5230\u7406\u60f3\u6548\u679c\uff0c\u6d88\u8017\u662f\u65e0\u6cd5\u63a5\u53d7\u7684\uff0c\u7efc\u5408\u6765\u8bf4\u4e0d\u9002\u5408\u7528\u4e8e\u5b9e\u65f6<\/p>\n<h4>\u4f18\u5316<\/h4>\n<p>\u4f46Diffusion Profile\u7684\u5206\u5e03\u548c\u9ad8\u65af\u51fd\u6570\u7c7b\u4f3c\uff0c\u5982\u4e0b\u56fe\u6240\u793a\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c84b8c33eb.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730970797430.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672c84b8c33eb.png\" alt=\"1730970797430.png\" \/><\/p><\/noscript>\n<p>\u8fd9\u610f\u5473\u7740\uff0c\u53ef\u4ee5<strong>\u901a\u8fc7\u7ed3\u5408\u4e0d\u540c\u53c2\u6570\u7684\u9ad8\u65af\u51fd\u6570\u6765\u8fd1\u4f3cDiffusion Profile<\/strong>\u3002\u9ad8\u65af\u51fd\u6570\u8fd8\u6709\u4e2a\u4f18\u70b9\uff1a<strong>\u53ef\u5206\u79bb\u6027\u548c\u5f84\u5411\u5bf9\u79f0\u6027<\/strong>\uff0c\u8fd9\u4f7f\u5f97\u9ad8\u65af\u51fd\u6570\u6ee1\u8db3\u5377\u79ef\u5206\u79bb\u7684\u9700\u6c42<\/p>\n<p>\u4f7f\u7528<strong>6<\/strong>\u4e2a\u9ad8\u65af\u51fd\u6570\u5373\u53ef\u62df\u5408\u76ae\u80a4\u7b49\u5e26\u6709<strong>3<\/strong>\u5c42Dipole\u7684Diffusion Profile<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca4b13e3d5.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730978981444.png\" \/><br \/ >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca4b13e3d5.png\" alt=\"1730978981444.png\" \/><br \/><\/noscript>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca5225d8d6.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730979094255.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca5225d8d6.png\" alt=\"1730979094255.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">w_i<\/span>\uff1a\u63a7\u5236\u53c2\u4e0e\u6c42\u548c\u7684\u9ad8\u65af\u51fd\u6570\u5f62\u72b6<\/li>\n<li>\u200b    <span class=\"katex math inline\">v_i<\/span>\uff1a\u65b9\u5dee<\/li>\n<li>\u200b    <span class=\"katex math inline\">r<\/span>\uff1a\u6563\u5c04\u8ddd\u79bb<\/li>\n<\/ul>\n<p>\u5728\u8bba\u6587\u4e2d\u5bf9\u76ae\u80a4\u7684\u62df\u5408\u7ed3\u679c\u6700\u7ec8\u7ed9\u51fa\u5982\u4e0b\u7684\u53c2\u6570\uff0c\u53ef\u89c1R\u3001G\u3001B\u901a\u9053\u62df\u5408\u51fa\u7684\u66f2\u7ebf\u6709\u6240\u4e0d\u540c\uff0c\u800c<strong>R\u901a\u9053\u66f2\u7ebf\u7684\u6269\u6563\u8303\u56f4\u6700\u8fdc\uff0c\u8fd9\u4e5f\u662f\u76ae\u80a4\u663e\u793a\u51fa\u7ea2\u8272\u7684\u539f\u56e0<\/strong>\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca57eac074.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730979186486.png\" \/><br \/ >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca57eac074.png\" alt=\"1730979186486.png\" \/><br \/><\/noscript>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca704490fc.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730979575616.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca704490fc.png\" alt=\"1730979575616.png\" \/><\/p><\/noscript>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c<strong>\u5728\u5b9e\u9645\u8ba1\u7b97\u65f6\uff0c\u53ea\u9700\u8ba1\u7b97R\u901a\u9053\u7684\u6563\u5c04\u6548\u679c\u3002<\/strong>\u56e0\u4e3a\u5373\u4fbf\u5982\u6b64\uff0c\u5bf9\u4e8e\u84dd\u7eff\u8272\u7684\u6563\u5c04\u6548\u679c\u4e5f\u662f\u53ef\u4ee5\u63a5\u53d7\u7684<\/p>\n<h4>\u5377\u79ef\u6838\u5927\u5c0f<\/h4>\n<p>\u5728\u5b9e\u73b0Blur\u6548\u679c\u65f6\uff0c\u6240\u7528\u5230\u7684\u5377\u79ef\u6838\u662f\u56fa\u5b9a\u5927\u5c0f\u7684\u3002\u4f46\u5728\u5b9e\u73b0SSSS\u65f6\uff0c\u60c5\u51b5\u4e0d\u540c\u4e86\uff0c<strong>\u56e0\u4e3a\u8fd9\u91cc\u5377\u79ef\u6838\u4ee3\u8868\u57fa\u4e8e\u7269\u7406\u7684Diffusion Profile\uff0c\u82e5\u662f\u56fa\u5b9a\u7684\uff0c\u5f97\u5230\u7684\u6a21\u7cca\u6548\u679c\u6574\u4f53\u90fd\u662f\u4e00\u6837\u7684\uff0c\u4e14\u56e0\u4e3a\u900f\u89c6\u6295\u5f71\u7684\u539f\u56e0\uff0c\u4e0d\u53ef\u80fd\u6bcf\u4e2apixel\u6240\u5360\u9762\u79ef\u90fd\u662f\u76f8\u540c\u7684\uff0c\u6240\u4ee5\u9700\u8981\u6839\u636e\u4e0d\u540c\u7684\u533a\u57df\u5c5e\u6027\u6765\u8c03\u6574\u5377\u79ef\u6838\u5927\u5c0f<\/strong><\/p>\n<p>\u51b3\u5b9a\u5377\u79ef\u6838\u5927\u5c0f\u7684\u56e0\u7d20\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>\u7f29\u653e\u7cfb\u6570<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca9c4cad3c.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730980280412.png\" \/><br \/ >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca9c4cad3c.png\" alt=\"1730980280412.png\" \/><br \/><\/noscript>\n\u7269\u7406\u610f\u4e49\u662f<strong>\u5377\u79ef\u6838\u5927\u5c0f\u5e94\u968fpixel\u6df1\u5ea6\u7684\u589e\u52a0\u800c\u51cf\u5c0f\uff0c\u4e14\u968f\u89c6\u573a\u89d2\u7684\u53d8\u5c0f\u800c\u53d8\u5927<\/strong><\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">f_y<\/span>\uff1a\u76f8\u673a\u7684\u89c6\u573a\u89d2<\/li>\n<li>\u200b    <span class=\"katex math inline\">p_d<\/span>\uff1a\u5f53\u524dpixel\u7684\u6df1\u5ea6\uff08\u975e[0,1]\uff09<\/li>\n<\/ul>\n<\/li>\n<li>SSS\u5bbd\u5ea6\uff1a\u9650\u5b9a\u5728\u4ec0\u4e48\u6837\u7684\u5c3a\u5ea6\u4e0a\u80fd\u591f\u770b\u5230\u6b21\u8868\u9762\u6548\u679c<\/li>\n<li>SSS\u5f3a\u5ea6\uff1a\u901a\u5e38\u4ee5\u8d34\u56fe\u7684\u5f62\u5f0f\u5b58\u5728\uff0c\u7528\u4ee5\u8868\u793a\u4e0d\u540c\u533a\u57df\u7684\u6b21\u8868\u9762\u5f3a\u5ea6<\/li>\n<\/ul>\n<h4>\u51e0\u4f55\u8fc7\u6ee4<\/h4>\n<p>\u5728\u5c4f\u5e55\u7a7a\u95f4\u51e0\u4e2a\u76f8\u90bb\u7684\u70b9\uff0c\u6b21\u8868\u9762\u6563\u5c04\u6750\u8d28\u662f\u8fde\u7eed\u7684\uff1b\u4f46\u5728\u4e16\u754c\u7a7a\u95f4\u4e0a\u4e0d\u4e00\u5b9a\u8fde\u7eed\u3002\u4e3a\u4e86\u907f\u514d\u6df7\u6dc6\u51e0\u4f55\u4e0a\u8fe5\u5f02\u76842\u5757\u6b21\u8868\u9762\u6750\u8d28\uff0c\u9020\u6210\u8fc7\u6e21\u4e0d\u81ea\u7136\u3002\u89e3\u51b3\u65b9\u6848\u662f<strong>\u6bd4\u8f83\u5f53\u524d\u91c7\u6837\u70b9\u548c\u5468\u56f4\u91c7\u6837\u70b9\u7684\u50cf\u7d20\u989c\u8272\u548c\u6df1\u5ea6\u503c<\/strong><br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672cae1f6027b.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730981395304.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672cae1f6027b.png\" alt=\"1730981395304.png\" \/><\/p><\/noscript>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>\u200b    <span class=\"katex math inline\">i_c<\/span>\uff1a\u5f53\u524dpixel\u7684\u989c\u8272<\/li>\n<li>\u200b    <span class=\"katex math inline\">o_c<\/span>\uff1a\u5468\u8fb9pixel\u7684\u989c\u8272<\/li>\n<li>\u200b    <span class=\"katex math inline\">i_d<\/span>\uff1a\u5f53\u524dpixel\u7684\u6df1\u5ea6<\/li>\n<li>\u200b    <span class=\"katex math inline\">o_d<\/span>\uff1a\u5468\u8fb9pixel\u7684\u6df1\u5ea6<\/li>\n<\/ul>\n<h2>\u5de5\u4e1a\u754c\u7684\u6d41\u7a0b<\/h2>\n<p>\u5927\u540d\u9f0e\u9f0e\u7684UE\u4f7f\u7528\u5230\u7684\u6d41\u7a0b\u5982\u4e0b\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/08\/672cf10408b52.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730998523630.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/08\/672cf10408b52.png\" alt=\"1730998523630.png\" \/><\/p><\/noscript>\n<p>\u5927\u81f4\u542b\u4e49\u662f\u5148\u5bf9\u9ad8\u5149\u548c\u6f2b\u53cd\u5c04\u5149\u5206\u5f00\u8ba1\u7b97\uff0c\u5bf9\u6f2b\u53cd\u5c04\u5149\u518d\u6b21\u5206\u79bb\uff0c\u5206\u6210\u6c34\u5e73\u7ad6\u76f4\u4e24\u6b21\u8ba1\u7b97\uff0c\u6700\u540e\u53e0\u52a0<\/p>\n<h1>\u5b9e\u73b0<\/h1>\n<p>\u8fd9\u91cc\u5148\u4e0d\u5206\u79bb\u6f2b\u53cd\u5c04\u548c\u9ad8\u5149<\/p>\n<h2>\u9ad8\u65af\u51fd\u6570<\/h2>\n<p><img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca5225d8d6.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730979094255.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca5225d8d6.png\" alt=\"1730979094255.png\" \/><\/p><\/noscript>\n<pre><code class=\"line-numbers\">\/\/\/ &lt;summary&gt;\n\/\/\/ \u9ad8\u65af\u51fd\u6570. \u589e\u52a0\u4e86FalloffColor\u989c\u8272\uff0c\u5bf9\u5e94\u4e0d\u540c\u989c\u8272\u901a\u9053\u7684\u503c\n\/\/\/ &lt;\/summary&gt;\n\/\/\/ &lt;param name=\"variance\"&gt; \u65b9\u5dee &lt;\/param&gt;\n\/\/\/ &lt;param name=\"radius\"&gt; \u6b21\u8868\u9762\u6563\u5c04\u7684\u6700\u5927\u5f71\u54cd\u8ddd\u79bb\u3002\u5355\u4f4dmm &lt;\/param&gt;\n\/\/\/ &lt;param name=\"falloffColor\"&gt; \u5149\u7ebf\u968f\u8ddd\u79bb\u589e\u52a0\u800c\u8870\u51cf\u7684\u7a0b\u5ea6, \u6570\u503c\u8d8a\u5c0f\u8868\u793a\u5bf9\u5e94\u65b9\u5411\u4e0a\u5149\u7ebf\u8870\u51cf\u5f97\u8d8a\u5feb\uff0c\u6570\u503c\u8d8a\u5927\u8868\u793a\u8870\u51cf\u5f97\u8d8a\u6162 &lt;\/param&gt;\n\/\/\/ &lt;returns&gt;&lt;\/returns&gt;\nstatic Vector3 SeparableSSS_Gaussian(float variance, float radius, Vector3 falloffColor)\n{\n    Vector3 result = Vector3.zero;\n\n    for (int i = 0; i &lt; 3; ++i)\n    {\n        float rr = radius \/ (0.001f + falloffColor[i]);\n        result[i] = Mathf.Exp(-(rr * rr) \/ (2f * variance)) \/ (2f * Mathf.PI * variance);\n    }\n\n    return result;\n}\n<\/code><\/pre>\n<h2>\u8fd1\u4f3cDiffusion Profile<\/h2>\n<p><img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca57eac074.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730979186486.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca57eac074.png\" alt=\"1730979186486.png\" \/><\/p><\/noscript>\n<pre><code class=\"line-numbers\">\/\/\/ &lt;summary&gt;\n\/\/\/ 6\u4e2a\u9ad8\u65af\u51fd\u6570\u62df\u54083\u4e2adipole\u66f2\u7ebf\n\/\/\/ &lt;\/summary&gt;\n\/\/\/ &lt;param name=\"radius\"&gt; \u6b21\u8868\u9762\u6563\u5c04\u7684\u6700\u5927\u5f71\u54cd\u8ddd\u79bb\u3002\u5355\u4f4dmm &lt;\/param&gt;\n\/\/\/ &lt;param name=\"falloffColor\"&gt; \u5149\u7ebf\u968f\u8ddd\u79bb\u589e\u52a0\u800c\u8870\u51cf\u7684\u7a0b\u5ea6, \u6570\u503c\u8d8a\u5c0f\u8868\u793a\u5bf9\u5e94\u65b9\u5411\u4e0a\u5149\u7ebf\u8870\u51cf\u5f97\u8d8a\u5feb\uff0c\u6570\u503c\u8d8a\u5927\u8868\u793a\u8870\u51cf\u5f97\u8d8a\u6162 &lt;\/param&gt;\n\/\/\/ &lt;returns&gt;&lt;\/returns&gt;\nstatic Vector3 SeparableSSS_Profile(float radius, Vector3 falloffColor)\n{\n    \/\/ \u53bb\u63890.233f * SeparableSSS_Gaussian(0.0064f, radius, falloffColor)\u3002\u7406\u7531\u662f\u8fd9\u4e2a\u662f\u76f4\u63a5\u53cd\u5c04\u5149\uff0c\u4e14\u8003\u8651\u4e86strength\u53c2\u6570\n    return 0.1f * SeparableSSS_Gaussian(0.0484f, radius, falloffColor) +\n           0.118f * SeparableSSS_Gaussian(0.187f, radius, falloffColor) +\n           0.113f * SeparableSSS_Gaussian(0.567f, radius, falloffColor) +\n           0.358f * SeparableSSS_Gaussian(1.99f, radius, falloffColor) +\n           0.078f * SeparableSSS_Gaussian(7.41f, radius, falloffColor);\n}\n<\/code><\/pre>\n<h2>\u8ba1\u7b97\u5377\u79ef\u6838\u6570\u636e<\/h2>\n<ol>\n<li>\u786e\u5b9a\u5377\u79ef\u8303\u56f4\uff1akernelList[i].w\n<pre><code class=\"line-numbers\">\/\/ \u5377\u79ef\u6838\u5148\u7ed9\u5b9a\u4e00\u4e2a\u9ed8\u8ba4\u7684\u534a\u5f84\u8303\u56f4\uff0c\u4e0d\u80fd\u592a\u5927\u4e5f\u4e0d\u80fd\u592a\u5c0f\uff0c\u6839\u636enTotalSamples\u8c03\u6574Range(\u5355\u4f4d\u662f\u6beb\u7c73mm)\n\/\/ \u5f97\u5230\u4e00\u4e2a\u524d\u534a\u4e3a\u8d1f\uff0c\u540e\u534a\u4e3a\u6b63\u7684\u6b65\u957f\u6570\u7ec4\uff0c\u5e76\u901a\u8fc7\u4e00\u4e2a\u6b65\u957f\u51fd\u6570\u6765\u63a7\u5236\u6b65\u957f\u503c\nfloat range = nTotalSamples &gt; 20.0f ? 3.0f : 2.0f;\nconst float exponent = 2.0f;    \/\/ \u6307\u5b9a\u6b65\u957f\u51fd\u6570\u7684\u5f62\u72b6.\u9ad8\u65af\u5206\u5e03\u7684\u7b80\u5316\u7248\uff0c\u8ddd\u79bb\u539f\u70b9\u8d8a\u8fdc\u7684\u6837\u672c\u6b65\u957f\u8d8a\u5927\nfloat step = 2.0f * range \/ (nTotalSamples - 1);    \/\/ \u6bcf\u6b21\u5377\u79ef\u7684\u504f\u79fb\u503c\nfor (int i = 0; i &lt; nTotalSamples; ++i)\n{\n   float o = -range + (float)i * step; \/\/ \u7b2ci\u6b65\u5377\u79ef\u7684\u603b\u504f\u79fb\u503c\n   float sign = o &lt; 0.0f ? -1.0f : 1.0f;\n   \/\/ \u5c06\u5f53\u524d\u7684range\u548c\u6700\u5927\u7684Range\u7684\u6bd4\u503c\u5b58\u5165alpha\u901a\u9053\n   kernelList.Add(new Vector4(0.0f, 0.0f, 0.0f, range * sign * Mathf.Abs(Mathf.Pow(o, exponent))));\n}\n<\/code><\/pre>\n<p>\u91c7\u7528Mathf.Pow(o, exponent)\uff0c\u6b63\u662f\u5229\u7528\u5230\u9ad8\u5206\u5206\u5e03\u7684\u7279\u6027\uff0c\u4e2d\u5fc3\u5468\u56f4\u70b9\u7684\u8d21\u732e\u5ea6\u6700\u5927\uff0c\u8d8a\u5f80\u4e24\u8fb9\u8d21\u732e\u5ea6\u8d8a\u4f4e\uff08\u7c7b\u4f3c\u4e8e\u91cd\u8981\u6027\u91c7\u6837\uff09<\/p>\n<\/li>\n<li>\n<p>\u8ba1\u7b97\u6743\u91cd\uff1akernelList[i].xyz<\/p>\n<p>\u8ba1\u7b97\u6bcf\u5377\u79ef\u8303\u56f4\u540e\uff0c\u9700\u8981\u77e5\u9053\u5377\u79ef\u8303\u56f4\u5185\uff0c\u6bcf\u4e2a\u70b9\u7684\u6bd4\u91cd<\/p>\n<pre><code class=\"line-numbers\">\/\/ \u8ba1\u7b97Kernel\u6743\u91cd\nfor (int i = 0; i &lt; nTotalSamples; ++i)\n{\n   float w0 = i &gt; 0 ? Mathf.Abs(kernelList[i].w - kernelList[i - 1].w) : 0.0f;     \/\/\u5de6\u90bb\u5c45\u7684\u6b65\u957f\u5dee\n   float w1 = i &lt; nTotalSamples - 1 ? Mathf.Abs(kernelList[i].w - kernelList[i + 1].w) : 0.0f; \/\/\u53f3\u90bb\u5c45\u7684\u6b65\u957f\u5dee\n   float area = (w0 + w1) \/ 2.0f;  \/\/ \u8be5\u91c7\u6837\u70b9\u7684\u6240\u5360\u957f\u5ea6\n\n   Vector3 t = area * SeparableSSS_Profile(kernelList[i].w, falloffColor); \/\/ \u7528\u5377\u79ef\u6b65\u957f\u8ba1\u7b97\u5f97\u5230\u989c\u8272\n   kernelList[i] = new Vector4(t.x, t.y, t.z, kernelList[i].w);\n}\n<\/code><\/pre>\n<\/li>\n<li>\u5c06\u6700\u4e2d\u95f4\u7684\u5143\u7d20\u79fb\u5230\u6570\u7ec4\u7684\u7b2c\u4e00\u4f4d\uff0c\u5728\u540e\u7eed\u8ba1\u7b97Blur\u65f6\uff0c\u4f18\u5316\u6027\u80fd\n<pre><code class=\"line-numbers\">\/\/ \u4f7f\u7528nSamples \/ 2\u8868\u793a\u4e2d\u95f4\u7684\u4f4d\u7f6e\uff0c\u518d\u4ece\u4e2d\u95f4\u5143\u7d20\u7684\u4f4d\u7f6e\u5f00\u59cb\uff0c\u5f80\u524d\u904d\u5386\u534a\u4e2a\u6570\u7ec4\uff0c\u5c06\u6240\u6709\u5143\u7d20\u90fd\u5411\u540e\u79fb\u52a8\u4e00\u4e2a\u4f4d\u7f6e\n\/\/ \u786e\u4fddkernel\u6570\u7ec4\u7684\u4e2d\u95f4\u5143\u7d20\u5904\u4e8e\u6700\u5bb9\u6613\u8bbf\u95ee\u7684\u4f4d\u7f6e\uff0c\u540e\u7eed\u5bf9kernel\u6570\u7ec4\u7684\u64cd\u4f5c\u66f4\u9ad8\u6548\nVector4 centerKernel = kernelList[nTotalSamples \/ 2];\nfor (int i = nTotalSamples \/ 2; i &gt; 0; --i)\n{\n   kernelList[i] = kernelList[i - 1];\n}\nkernelList[0] = centerKernel;\n<\/code><\/pre>\n<\/li>\n<li>\u5c06\u6743\u91cd\u5f52\u4e00\u5316\uff0c\u5373\u6240\u6709\u70b9\u7684\u6743\u91cd\u548c\u4e3a1\n<pre><code class=\"line-numbers\">\/\/ kernelList[i].xyz = subsurfaceColor * kernelList[i].xyz \/ \u2211kernelList[i].xyz\nVector4 sum = Vector4.zero;\nfor (int i = 0; i &lt; nTotalSamples; ++i)\n{\n   sum.x += kernelList[i].x;\n   sum.y += kernelList[i].y;\n   sum.z += kernelList[i].z;\n}\nfor (int i = 0; i &lt; nTotalSamples; ++i)\n{\n   kernelList[i] = new Vector4(kernelList[i].x \/ sum.x, kernelList[i].y \/ sum.y, kernelList[i].z \/ sum.z, kernelList[i].w);\n}\n<\/code><\/pre>\n<\/li>\n<li>\u5c06\u6743\u91cd\u6bd4\u548c\u4e00\u4e2a\u53ef\u5f00\u653e\u4e14\u53ef\u4fee\u6539\u7684\u53c2\u6570lerp\uff0c\u4ece\u800c\u624b\u52a8\u63a7\u5236\u6f2b\u53cd\u5c04\u6548\u679c\n<pre><code class=\"line-numbers\">var tempKernel = kernelList[0];\ntempKernel.x = Mathf.Lerp(1.0f, kernelList[0].x, subsurfaceColor.x);\ntempKernel.y = Mathf.Lerp(1.0f, kernelList[0].y, subsurfaceColor.y);\ntempKernel.z = Mathf.Lerp(1.0f, kernelList[0].z, subsurfaceColor.z);\nkernelList[0] = tempKernel;\n\nfor (int i = 1; i &lt; nTotalSamples; ++i)\n{\n   tempKernel = kernelList[i];\n   tempKernel.x *= subsurfaceColor.x;\n   tempKernel.y *= subsurfaceColor.y;\n   tempKernel.z *= subsurfaceColor.z;\n   kernelList[i] = tempKernel;\n}\n<\/code><\/pre>\n<\/li>\n<\/ol>\n<h2>\u5206\u79bb\u7684\u9ad8\u65af\u6a21\u7cca<\/h2>\n<p>\u5206\u4e3a\u6c34\u5e73\u548c\u7ad6\u76f4\u7684\u6a21\u7cca<\/p>\n<p>\u7f29\u653e\u7cfb\u6570\uff1a<\/p>\n<p><img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca9c4cad3c.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1730980280412.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/07\/672ca9c4cad3c.png\" alt=\"1730980280412.png\" \/><\/p><\/noscript>\n<pre><code class=\"line-numbers\">_SSSSMaterial.SetFloat(\"_DistanceToProjectionWindow\", 1.0f \/ (0.5f * Mathf.Tan(math.radians(renderingData.cameraData.camera.fieldOfView))));\n<\/code><\/pre>\n<pre><code class=\"line-numbers\">float  SSSSIntensity = _SSSSScale * _CameraDepthTexture_TexelSize.x;    \/\/ \u6c34\u5e73\u65b9\u5411\u4e3a_CameraDepthTexture_TexelSize.x\uff0c\u7ad6\u76f4\u65b9\u5411\u4e3a_CameraDepthTexture_TexelSize.y\nfloat4 sceneColor = _MainTex.SampleLevel(Smp_ClampU_ClampV_Linear, uv, 0);\n\nfloat3 SSSSBlur(float3 sceneColor, float2 uv, float2 SSSSIntensity)\n{\n    float eyeDepth = GetLinearEyeDepth(GetDeviceDepth(uv));\n    float blurLength = _DistanceToProjectionWindow \/ eyeDepth;  \/\/ \u7f29\u653e\u7cfb\u6570\n\n    float2 uvOffset = blurLength * SSSSIntensity;\n    float3 blurColor = sceneColor * _KernelArray[0].rgb;\n\n    [unroll(64)]\n    for(int i = 1; i &lt; _Sample_Nums; ++i)\n    {\n        float2 SSSSUV = uv + uvOffset * _KernelArray[i].a;\n\n        float3 SSSSSceneColor = _MainTex.SampleLevel(Smp_ClampU_ClampV_Linear, SSSSUV, 0).rgb;\n        float  SSSSEyeDepth = _CameraDepthTexture.SampleLevel(Smp_ClampU_ClampV_Linear, SSSSUV, 0);\n\n        float DPTimes300 = _DistanceToProjectionWindow * 300;    \/\/ \u7ecf\u9a8c\u53c2\u6570\n        float SSSSSCale = saturate(DPTimes300 * SSSSIntensity * abs(eyeDepth - SSSSEyeDepth));\n        SSSSSceneColor = lerp(SSSSSceneColor, sceneColor, SSSSSCale);\n        blurColor += _KernelArray[i].rgb * SSSSSceneColor;\n    }\n\n    return blurColor;\n}\n<\/code><\/pre>\n<h1>Diffuse\u5149\u7167\u9009\u62e9<\/h1>\n<p>UE\u9009\u62e9\u7684\u662fDisney\u63d0\u51fa\u7684Burley\u6a21\u578b<\/p>\n<pre><code class=\"line-numbers\">\/\/ [Burley 2012, \"Physically-Based Shading at Disney\"]\n\/\/ Lambert\u6f2b\u53cd\u5c04\u6a21\u578b\u5728\u8fb9\u7f18\u4e0a\u901a\u5e38\u592a\u6697\uff0c\u800c\u901a\u8fc7\u5c1d\u8bd5\u6dfb\u52a0\u83f2\u6d85\u5c14\u56e0\u5b50\u4ee5\u4f7f\u5176\u5728\u7269\u7406\u4e0a\u66f4\u5408\u7406\uff0c\u4f46\u4f1a\u5bfc\u81f4\u5176\u66f4\u6697\n\/\/ \u6839\u636e\u5bf9Merl 100\u6750\u8d28\u5e93\u7684\u89c2\u5bdf\uff0cDisney\u5f00\u53d1\u4e86\u4e00\u79cd\u7528\u4e8e\u6f2b\u53cd\u5c04\u7684\u65b0\u7684\u7ecf\u9a8c\u6a21\u578b\uff0c\u4ee5\u5728\u5149\u6ed1\u8868\u9762\u7684\u6f2b\u53cd\u5c04\u83f2\u6d85\u5c14\u9634\u5f71\u548c\u7c97\u7cd9\u8868\u9762\u4e4b\u95f4\u8fdb\u884c\u5e73\u6ed1\u8fc7\u6e21\n\/\/ Disney\u4f7f\u7528\u4e86Schlick Fresnel\u8fd1\u4f3c\uff0c\u5e76\u4fee\u6539\u63a0\u5c04\u9006\u53cd\u5c04\uff08grazing retroreflection response\uff09\u4ee5\u8fbe\u5230\u5176\u7279\u5b9a\u503c\u7531\u7c97\u7cd9\u5ea6\u503c\u786e\u5b9a\uff0c\u800c\u4e0d\u662f\u7b80\u5355\u4e3a0\nfloat3 Diffuse_Burley( float3 DiffuseColor, float Roughness, float NoV, float NoL, float VoH )\n{\n    float FD90 = 0.5 + 2 * VoH * VoH * Roughness;\n    float FdV = 1 + (FD90 - 1) * pow5( 1 - NoV );\n    float FdL = 1 + (FD90 - 1) * pow5( 1 - NoL );\n    return DiffuseColor * ( (1 \/ PI) * FdV * FdL );\n}\n<\/code><\/pre>\n<h2>\u6548\u679c<\/h2>\n<p>\u4ec5\u6f2b\u53cd\u5c04\u65e0\u9ad8\u5149\uff0c\u518dSSSS\u6548\u679c\u5982\u4e0b\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/673245cc2b299.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1731347902201.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/673245cc2b299.png\" alt=\"1731347902201.png\" \/><\/p><\/noscript>\n<h1>\u9ad8\u5149<\/h1>\n<p>\u9ad8\u5149\u90e8\u5206\u6709\u4e9b\u7e41\u7410\uff0c\u4e0d\u80fd\u8d70\u6b63\u5e38\u7684\u5ef6\u8fdf\u6e32\u67d3\u6d41\u7a0b\uff0c\u9700\u8981\u4fee\u6539\u5ef6\u8fdf\u5149\u7167\u7b97\u6cd5\uff0c\u5148\u8ba1\u7b97diffuse\uff0c\u7136\u540eSSSS\uff0c\u6700\u540e\u518d\u8fdb\u884c\u5ef6\u8fdf\u5149\u7167\u6765\u8ba1\u7b97specular\u3002\u91cd\u70b9\u5728\u4e8especular\u7b97\u6cd5\u5982\u4f55\u6289\u62e9<\/p>\n<h2>NDF<\/h2>\n<p>UE\u7684\u76ae\u80a4\u6e32\u67d3\u91c7\u7528<strong>\u53cc\u955c\u53f6\u9ad8\u5149<\/strong>\uff08Dual Lobe Specular\uff09\uff0c\u7531\u4e24\u4e2a\u72ec\u7acb\u7684\u9ad8\u5149\u955c\u53f6\u7ec4\u6210\uff0c\u5404\u81ea\u4f7f\u7528\u4e0d\u540c\u7684roughness\u2014\u2014\u5373\u4f7f\u7528\u4e24\u4e2a\u72ec\u7acb\u7684roughness\uff0c\u8ba1\u7b97\u4e24\u4e2a\u76f8\u540c\u7684NDF\uff0c\u518d\u5bf9\u4e24\u4e2aroughness\u6df7\u5408\uff0cUE\u7684\u6df7\u5408\u6bd4\u4f8b\u662f\u56fa\u5b9a\u7684\uff1a\u4e3broughness\u4e3a0.85\uff0c\u6b21roughness\u4e3a0.15<\/p>\n<pre><code class=\"line-numbers\">half  _LodeA;\nhalf  _LodeB;\n\n\/\/ GGX \/ Trowbridge-Reitz\n\/\/ [Walter et al. 2007, \"Microfacet models for refraction through rough surfaces\"]\n\/\/ \u5728\u6d41\u884c\u7684\u6a21\u578b\u4e2d\uff0cGGX\u62e5\u6709\u6700\u957f\u7684\u5c3e\u90e8\u3002\u800cGGX\u5176\u5b9e\u4e0eBlinn (1977)\u63a8\u5d07\u7684Trowbridge-Reitz\uff08TR\uff09\uff081975\uff09\u5206\u5e03\u7b49\u540c\u3002\u7136\u800c\uff0c\u5bf9\u4e8e\u8bb8\u591a\u6750\u8d28\u800c\u8a00\uff0c\u5373\u4fbf\u662fGGX\u5206\u5e03\uff0c\u4ecd\u7136\u6ca1\u6709\u8db3\u591f\u957f\u7684\u5c3e\u90e8\nfloat NDF_GGX( float roughness2, float NoH )\n{\n    const float a2 = pow2(roughness2);\n    const float NoH2 = pow2(NoH);\n    const float d = PI * pow2(NoH2 * (a2 - 1.f) + 1.f);\n\n    if(d &lt; FLT_EPS) return 1.f;\n\n    return a2 \/ d;\n}\n\nfloat lobeARoughness = brdfData.roughness * brdfData.LobeA;\nlobeARoughness = lerp(1.f, lobeARoughness, saturate(brdfData.opacity * 10.0f));\nfloat lobeBRoughness = brdfData.roughness * brdfData.LobeB;\nlobeBRoughness = lerp(1.f, lobeBRoughness, saturate(brdfData.opacity * 10.0f));\nfloat lobeMix = 0.15f;\n\n\/\/ AverageRoughness: roughness\nfloat AverageAlpha2 = Pow4(AverageRoughness);\nfloat Lobe0Alpha2 = Pow4(Lobe0Roughness);\nfloat Lobe1Alpha2 = Pow4(Lobe1Roughness);\nfloat D = lerp(NDF_GGX(Lobe0Alpha2, brdfData.NoH), NDF_GGX(Lobe1Alpha2, brdfData.NoH), LobeMix);\n<\/code><\/pre>\n<p><img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/673374ddd3191.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1731425489009.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/673374ddd3191.png\" alt=\"1731425489009.png\" \/><\/p><\/noscript>\n<h2>\u51e0\u4f55\u9879<\/h2>\n<p>\u4f7f\u7528 Joint-Smith\u9879\uff08\u8054\u5408\u53f2\u5bc6\u65af\uff09\u7684\u4e00\u79cd\u8fd1\u4f3c\u9ad8\u6548\u65b9\u6848\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/6733750f45133.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1731425538463.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/6733750f45133.png\" alt=\"1731425538463.png\" \/><\/p><\/noscript>\n<pre><code class=\"line-numbers\">float Vis_SmithJointApprox( float a2, float NoV, float NoL )\n{\n    float a = sqrt(a2);\n    float Vis_SmithV = NoL * ( NoV * ( 1 - a ) + a );\n    float Vis_SmithL = NoV * ( NoL * ( 1 - a ) + a );\n    return 0.5 * rcp( Vis_SmithV + Vis_SmithL );\n}\n\nfloat G = Vis_SmithJointApprox(AverageAlpha2, brdfData.NoV, brdfData.NoL);\n<\/code><\/pre>\n<h2>Fresnel<\/h2>\n<p>\u7528\u666e\u901a\u7684Schlick-Fresnel\u65b9\u6848\u5373\u53ef\uff1a<\/p>\n<pre><code class=\"line-numbers\">float3 SchlickFresnel(float HdotV, float3 F0)\n{\n    float m = clamp(1-HdotV, 0, 1);\n    float m2 = m * m;\n    float m5 = m2 * m2 * m; \/\/ pow(m,5)\n    return F0 + (1.0 - F0) * m5;\n}\n\nfloat3 F = SchlickFresnel(brdfData.HoV, brdfData.F0);\n<\/code><\/pre>\n<h2>\u6548\u679c<\/h2>\n<p>\u5f97\u5230\u7684\u6548\u679c\u5982\u4e0b\uff1a<br \/>\n<img decoding=\"async\"   class=\"lazyload\" data-src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/67337572d3d4d.png\" src=\"https:\/\/cdn.jsdelivr.net\/gh\/moezx\/cdn@3.0.2\/img\/svg\/loader\/trans.ajax-spinner-preloader.svg\" onerror=\"imgError(this)\"  alt=\"1731425637246.png\" \/><\/p >\n<noscript><img decoding=\"async\" src=\"https:\/\/a1.boltp.com\/2024\/11\/12\/67337572d3d4d.png\" alt=\"1731425637246.png\" \/><\/p><\/noscript>\n<h1>\u9879\u76ee\u94fe\u63a5<\/h1>\n<p>https:\/\/github.com\/chenglixue\/Separable-Subsurface-Scatter\/tree\/main<\/p>\n<h1>Reference<\/h1>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.cnblogs.com\/timlly\/p\/11098212.html\" target=\"_blank\"  rel=\"nofollow\" >\u5256\u6790Unreal Engine\u8d85\u771f\u5b9e\u4eba\u7c7b\u7684\u6e32\u67d3\u6280\u672fPart 1 - \u6982\u8ff0\u548c\u76ae\u80a4\u6e32\u67d3<\/a><\/p>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.jianshu.com\/p\/d02b475a09c1\" target=\"_blank\"  rel=\"nofollow\" >\u7b80\u8c08\u5b9e\u65f6\u76ae\u80a4\u6e32\u67d3\u4e4bSSSS(\u53ef\u5206\u79bb\u6b21\u8868\u9762\u6563\u5c04\u6a21\u578b-SeparableSSS)<\/a><\/p>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/zhuanlan.zhihu.com\/p\/617658356\" target=\"_blank\"  rel=\"nofollow\" >\u3010\u8be6\u89e34S\u76ae\u80a4\u3011\u53ef\u5206\u79bb\u6b21\u8868\u9762\u6563\u5c04Separable SSS\uff08\u542b\u900f\u5c04\u9879\uff09<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u524d\u8a00 \u524d\u6587\u63d0\u5230\u4e86\u5982\u4f55\u5b9e\u73b0\u9002\u5408\u4e8e\u79fb\u52a8\u7aef\u7684\u9884\u79ef\u5206\u6b21\u8868\u9762\u6563\u5c04\u6548\u679c\uff0c\u4f46\u8fd9\u79cd\u6548\u679c\u5e76\u4e0d\u662f\u7279\u522b\u597d\uff0c\u5bf9\u4e8ePC\u7aef\u8fd8\u6709\u5176\u4ed6\u6548\u679c\u66f4\u597d\u7684\u5b9e\u65f6\u6e32\u67d3\u65b9\u6848\uff0c\u4e14\u4e24 &#8230;<\/p>","protected":false},"author":1,"featured_media":273,"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\/300"}],"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=300"}],"version-history":[{"count":1,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/300\/revisions"}],"predecessor-version":[{"id":301,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/posts\/300\/revisions\/301"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=\/wp\/v2\/media\/273"}],"wp:attachment":[{"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=300"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chenglixue.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}