Specular AA

• problem
• reference
• basic principle
  • NV 16
  • 19
• implementation

problem

reference

• NV 16 Filtering Distributions of Normals for Shading Antialiasing

• 19 Improved Geometric Specular Antialiasing

• shadertoy realization https://www.shadertoy.com/view/WssyR7

basic principle

NV 16

filters a distribution of microfacet normals in the domain of microfacet slopes by estimating the filtering kernel using derivatives of a halfway vector between incident and outdoing directions. 在一个很小的面积内对BSDF做filtering 基于假设：积分区域远小于eye和light source到surface point的距离，上述公式可以简化为 Fresnel 和 Geometry项都属于[0,1]范围，变化较为平缓，可视为常数。

• problem filters a distribution of microfacet normals in the domain of microfacet slopes by estimating the filtering kernel using derivatives of a halfway vector between incident and outdoing directions. 越接近gazing angle，hz越小，误差越大。

19

• estimates the derivatives in a projected halfvector space instead of slope space

• optimization for deferred shading

implementation

• forward

• previous

• 

• improved