Adds additional images to the sprite that can be used with shaders. The image set with SetSpriteImage is used as texture stage 0, and this command will let you set stages 1 to 7. These additional images do not play any part in animation or shape calculations. Note that the sprite will have the same UV coordinates for each texture so it is recommended that the images have the same dimensions, or use power of 2 images to avoid UV conversions on mobile devices where images might be scaled.
SetSpriteAdditionalImage ( iSpriteIndex, iImageIndex, iStage )