There is no way to apply a true multidimensional lookup to a pixel image without SGIX_pixel_texture. In some cases, pixel maps and color tables may be used as a substitute. Blending, accumulation buffer operations, or scale/bias operations may be used when the function to be applied is linear and each channel is independent. In other cases, the application will have to perform the lookup on the host or draw a textured point for each pixel in the image.