   detail textures in OpenGL
  Hi,I want to create a detail texture effect on top of the texture already ona model, for example skid marks on a road texture. I know its possible tocreate 2 textures for a polygon, but I don't know how to modify the texturedynamically once its been bound.Essentially what I want is procedural textures.How is this done?ThanksMark   
  Best not to use procedural textures for this. You can just draw another texture over the top (eg do the blending in the frame buffer, not the image data). Have a look at this. Decals. (american word for 'sticker' I think)   