[zj]

Hi, I test it on the teapot. It is rendered with different light angle and absorbing coefficient.
It must use multiple shadow maps for arbitrary geometry with a lot of overlapping parts. Ideally, you should use a semi-dome of light, but it is not practical.
I don't know how to use softshadow instead since we need to sample the shadow map for distance.
I want the shader to be easy to control and work at all view point. Not has dozens of parameters to tweak and only works as "back lighting".