Hi
I like to
toy with the renderer very much and currently i'm trying to implement a software tcGen of GL_EYE_LINEAR which would, in theory, map the UV's from the viewport's projection (which could make for nice fake framebuffer effects like refractions/reflections if gone a little further)
Only problem is i'm having trouble translating matrixes from the projection to the world. Q3 doesn't come with much functions for matrix manipulation, and code on the internet to imitate GL_EYE_LINEAR (like for GLES) really calls for them.
I *could* DoTheRightThing and use a FBO...but i'm intentionally targeting the low end, the ~2000 target for technical and aesthetic reasons, among other plans like libretro.
I was inspired by
this which pulls off refraction by GL_EYE_LINEAR'ing a pass with a rendertotexture of the view before drawing the water. The reflection is a static cubemap and the ripples are the standard procedural heightmap though.