I'm trying to implement Variance Shadow Mapping. As I searched around I found many sites mentioned that frontface culling could reduce self-shadowing artifacts, but I failed to generate shadow map whenever I turned on frontface culling, and I think it's reasonable, because all the front facing triangle would be culled out. I mean let's imagine your eyes are camera and there's a counter-clock winding(front facing) triangle in front of you, then you do a frontface culling and throw the triangle away, now how could you get the depth of the back face of that triangle? Could someone explain this to me?
another question is: when I render depth to texture, OpenGL would convert x and y from normal device coordinate to texture coordinate(from [-1, 1] to [0, 1]), does the same goes to z axis?