Hot on the heels of version 2.4.3, here comes a quick fix that I found while testing on a machine with GeForce FX 5200. While the basic engine works fine now with OpenGL 2.0 and FBOs, the FX series of GPUs doesn't support vertex texture fetch (sampling from textures in the vertex shader). This is described nicely in an OpenGL 2.0 paper by NVIDIA. One can check for GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS to see if the GPU supports that, and the GeForce FX returns zero as expected (there's no XP report, but the Linux driver shows it). Newer GPUs (including GeForce 6xxx series) support vertex texture fetch properly. This goes to show that it never hurts to do some additional testing with a variety of hardware. The game now does this, and falls back to a shader that is visually not that different from the original (drivers that DO support vertex texture fetch still use the default shader).