Patent ID: 6856323

Claim:
A method for rendering an image layer scene, comprising the steps of: (a) defining a scene of image layer elements; (b) rendering in a computer the elements of the image layer scene over a full black background to obtain color components for each pixel of the image layer scene rendered over full black; (c) rendering the elements of the image layer scene over a white background to obtain color components for each pixel of the image layer scene rendered over full white; and (d) combining the color components for each pixel of the image layer scene rendered over full black with the color components for each corresponding pixel of the image layer scene rendered over full white to form the rendered image layer scene by, for each corresponding pixel of the image layer scene rendered over full black and full white: determining an alpha value for the pixel a one plus the value of a single color component of the pixel from the image layer scene rendered over full black minus the value of the same color color component of the corresponding pixel from the image layer scene rendered over full white; setting all of the color component values of the pixel to zero if the alpha value for the pixel equals zero; otherwise setting the color component values of the pixel to the corresponding color component values of the corresponding pixel from the image layer scene-rendered over full black divided by, the alpha value for the pixel.