Microfacet Models for Refraction through Rough Surfaces这篇论文。。。名字被我忘记了 找了好久。。。之前存电脑里的ggx beckmann找的过程中发现另一篇论文An Introduction to BRDF Modelsbrdf是四维的函数基于物理的渲染 包括pb shading//brdf那套 还有能量守恒 normalize brdfpb light