Wrapped Diffuse

URP的CommonLighting.hlsl中ComputeWrappedDiffuseLighting方法的依据：

http://blog.stevemcauley.com/2011/12/03/energy-conserving-wrapped-diffuse/

ComputeWrappedPowerDiffuseLighting方法依据：

http://blog.stevemcauley.com/2013/01/30/extension-to-energy-conserving-wrapped-diffuse/

以及博客下的评论