My application renders a large terrain (~294K trianges) with texture mapping. This works fine on most of my test PCs, but on one laptop the terrain is rendering white, i.e. as if there is no texture mapping on the terrain. Small patches of terrain DO end up being texture mapped, but most is not. Furthermore, as I shift the angle of view of my camera, in some cases the terrain that is not being texture mapped shows up as "noise" - all black screen with little blue&red lines drawn through it. My rendering engine uses a lot of optimizing of the terrain, drawing with big quads, or triangle fans, etc, to minimize the # of triangles used (294K is the worst case), but I have a debug mode that uses all trianges. When I use that version on the laptop with problems, the terrain DOES render with texture correctly, but only for about 0.1 seconds, at which point the texture disappears and the landscape is white. My guess is that I am overloading the graphic processor''s memory, but would like to hear other conjectures. I''ve tried many optimization techniques - turning off mipmaps, using GL_RGB4, setting the priority of the textures to 1, etc., all to no avail.

As you said yourself with regards to texture-memory, you most likely have a leak somewhere. Do you build VBO''s continuosly and forget to ''deallocate'' them at times?
Sorry, no other ideas than that.

I''m not using VBO''s, just GL_TRIANGLES rendered using display lists (for my debug version, no tesselation code). So the terrain gets built once, then rendered by calling the appropriate display list.

I think you just ean out of vga memory. I have the same issue if i try my flight simulator on vga cards <64Mb. Terrain texture (which is about 16Mb) is white. On vga cards with more than 64Mb it runs with no problem at all.