Pixel collision is "oldschool", not really used almost at all nowadays. But if you really want to do that in OpenGL, you should keep texture data in memory and make own GetPixel function to read from it. Same texture data that you pass on glTexImage2D when loading them. OpenGL itself offers glReadPixels ( http://www.opengl.org/documentation/...eadpixels.html ) but you may find it as much slower choice.

Suggesting geometrical; circle, rectangle, line etc... collision instead.