AI 中文总结
本文提出一种基于微面元理论的类漫反射BRDF，支持初等表达式评估与重要性采样，精确处理Smith遮蔽下所有散射阶次，并在掠射角下集中反射光，通过对比实验验证效果。
AI 中文摘要
我们基于微面元理论推导出一种新颖的类漫反射BRDF。其主要新颖之处在于，该BRDF在评估和重要性采样方面均允许初等表达式，同时在Smith遮蔽假设下精确考虑所有散射阶次。因此，它首次解决了此类构造是否可能的问题。在实践中，该BRDF在法向入射时产生朗伯反射，并随着入射角接近掠射角，逐渐将反射光集中在镜面方向附近。我们通过将渲染结果与朗伯BRDF及最先进的随机微面元BRDF进行比较来展示这一效果。
英文摘要
We derive a novel diffuse-like BRDF based on microfacet theory. Its main novelty lies in the fact that it admits an elementary expression for both evaluation and importance sampling, while accounting exactly for all scattering orders under the Smith shadowing assumption. As such, it is the first to settle the question of whether such a construction was possible. In practice, the BRDF produces Lambertian reflectance at normal incidence and progressively concentrates reflected light around the mirror direction as incidence approaches grazing. We showcase this effect by comparing rendering results against Lambertian and state-of-the-art stochastic microfacet BRDFs.
