A multi-processor system for hidden-surface-removal

Abstract

Hidden-surface algorithms have attracted many researchers interested in creating realistic images. Many algorithms have been developed for hidden-surface removal. Different forms of "coherences" are used in order to reduce the computing required to generate a realistic image without hidden surfaces. We propose a hidden-surface removal system which uses many loosely coupled processors connected in parallel. All processors execute the same code while concurrently working on different portions of the screen. The original scene is partitioned in n equal segments, where n is the number of processors. Each processor works on a specified window of the scene. This requires additional clipping operations for each processor. Also, as the screen is partitioned into many disjoint areas, any "coherence" used by the hidden-surface algorithm is lost. Thus, each processor has to reset its segment list. The above options result in more work for each processor, limiting the gain in speed expected by displaying several processors.This scheme has been simulated for different types of scenes using 2, 4, 8 and 16 processors. Our simulation study shows that for lower values of n, the clipping time is much lower than the hidden-surface-removal time for a processor. For more than 16 processors, the clipping time is comparable to, or more than, the hidden-surface-removal time. We discuss implications of the partitioning of the scene and discuss methods to improve the scheme by using a superviser to utilize all processors efficiently.The proposed system will be very useful in many interactive graphics applications requiring fast display of realistic images.