I am using a GeForce4 that supports 4 texture units. I have written a piece of code that is basically similar to the “Anisotropic Bump Mapping” that is part of the NVidia Effects Browser. The demo uses 4 texture units:
TEX0: tangentmap (RGB)
TEX1: texcoords are the L vector
TEX2: texcoords are the H vector, texture is a phong lookup texture
TEX3: the decal texture (RGBA)
I am trying to expand this demo with depth-based shadow mapping that would consume yet another texture unit. Unfortunately, I am not that experienced, so I have no idea, how to effectively combine these two techniques. Does anyone has an idea, how I can achieve this, but by still using this bump mapping technique?