SIGGRAPH read: Real-time polygonal-light shading with linearly transformed cosines

See this year's an article Siggraph,real-time polygonal-light shading with linearly transformed cosines, a relatively concise solution to the complex BRDF in the spherical polygon area of the integration problem.

Roughly swept, like this problem-solving approach, mathematically direct and powerful, to achieve easy verification:

1. Linearly transformed cosines can effectively fit a variety of BRDF distribution, performance roughness, anisotropy, Skewness, the left is ground Truth, the right is Ltcs approximation ggx;

2. linearly transformed cosines resolves integrable (analytically integratable) on the polygon area on the sphere.

SIGGRAPH read: Real-time polygonal-light shading with linearly transformed cosines