I’m working on an app where I want to do some fancy environment mapping with cubemaps. I have already wrapped a surface with a normal cubemap using glTexGen. It’s similar to a normalization cubemap, except that mine is animated with ripples so all the normals move around a bit.
I want to use these normals to calculate reflection vectors that point into my background cubemap. I already know how to do this with ARB_fragment_program and I assume I can do it with ARB_fragment_shader (I just haven’t bothered to learn that one yet).
I’m just curious if there are other methods for doing this type of texture indirection without using fragment programs. Are there any? Maybe some sneaky multipass or multitexture tricks that I don’t know about?