My lightmaps are completely gray scale, stored as RGB 24-bit, and rendered with no lighting. Every pixel in the texture is a grayscale shade, but I am seeing grainy splotches of red and green when rendering. I am using GL_LINEAR for the mag filter, which is what is used at the distance in the image below. I am not using texture compression in this shot. I increased the screenshot’s saturation so the problem would be more easily visible.
You can see in this shot that the pixels are horrendous. This is a smooth-blended grayscale image, and it is getting displayed with what looks like severe compression artifacts: