A small update, just to let you know that the glitches are hopefully all ironed out, and the tangent stuff is now all computed on the CPU (with exactly the same method as Blender so even baked maps should work correctly). Here's a little test pic: http://imgur.com/HPJ76 The roof on the left is parallaxed/normal mapped, the roof on the right isn't. I think it looks a little better! Since the parallax effect is most noticeable up close, it only gets applied when objects are closer than 65m away, and is gradually scaled up in quality as the object comes closer (The cutoff is done with an if statement, with some possible caveats depending on what the GLSL compiler does under the hood... though it should save clock cycles in almost all cases). Normal mapping is always on, though a similar trick could be used for that. I'll probably release some source code over the weekend if any people want to play with it, though be warned that it's still very much a work-in-progress.