1. A method for blending a variable number of textures during rendering of a computer generated image, the method comprising the steps of: (1) extracting at least a first mask and a second mask from a first texture by applying scale and bias operations to the first texture; (2) blending a second texture and a third texture in accordance with the first mask to form a first image; and (3) blending the first image and a fourth texture in accordance with the second mask to form a second image.