I am writing a simple game using OpenGL, and I am seeing black speckles at the edges of polygons on the floor and ceiling, as if somehow they aren't lining up properly. The speckes do not appear when I look straight up or down. Is this a problem with my program or with OpenGL? I am using Mesa GL with DRI (Radeon 7500).

Screenshots and video

Do you use mipmapping for your textures? I don't have the codec for playing your AVI, but looking at the screenshots it appears that the black spots appear more frequent the further away from the near clip plane you get. My first thought is that there is a lack of mipmapping, or that somehow the different mipmap levels aren't being lined up properly, though that is just a guess.

Maybe post a bit of the code you use for setting up the textures in OpenGL...

It doesn't look like depth fighting to me, but that is also a possibility. What are your near and far clip planes set at? Trying to tighten that up might help too. If you have too big of a distance between them, your precision suffers, especially further away.

C source
Tarball with source, makefile and game data

To compile, run make (requires SDL, OpenGL, and SDL_Image). To run the game, run './game -nofs dukedc6.map'

I am using mipmaps; however, the problem also occurs when I turn off textures (glDisable(GL_TEXTURE_2D)). I don't think it's depth fighting, I can reduce the far clipping plane and see the cutoff ahead. I can overlap the textures some, which seems to help, but the only way to eliminate the problem with this method is to overlap them so much that the floor visibly hangs over.