Patent ID: 7106326

Claim:
A graphical processing system comprising: a computational unit; a processing unit coupled to the computational unit through a communication bus; wherein the computational unit is configured to transfer coordinates C 1 of a point P with respect to a first space to the processing unit; wherein, in response to receiving the coordinates C 1 , the processing unit is configured to: (a) transform the coordinates C 1 to determine map coordinates s and t and a depth value D p for the point P, (b) access a neighborhood of depth values from a memory using the map coordinates s and t, (c) compare the depth value D P to the depth values of said neighborhood to generate a vector of binary results of the comparisons, and (d) transfer the vector to the computational unit through the communication bus; wherein, in response to receiving the vector, the computational unit is configured to (e) filter the binary results of the comparisons to determine a shadow fraction; and wherein the communication bus is configured with minimum transfer bandwidth sufficient for the rate of transfer of the coordinates C 1 and the vector.