I am using a texture that has "tiled" content. Say for instance that the texture is 512x512 pixels, and that it contains a green, blue, yellow and red square, each 256x256 pixels. Now I want to restrict texturing so that only one portion of my tile-texture is being used. I.e. I only want to use the green (upper left) portion of my texture when texturing my primitives. For contents outside (in the >0.5 texture address space) I want it to be handled like when sampling outside of the physical texture. Is there a way to accomplish this (or similar), without manually changing the texture coordinates of the vertices?