US Patent 7277098 Apparatus and method of an improved stencil shadow volume operation

The computer graphics system is configured to improve the performance of a stencil shadow volume method for rendering shadows. The apparatus and methods utilize a combination of compressed and uncompressed stencil buffers in coordination with compressed and uncompressed depth data buffers. An uncompressed stencil buffer is capable of storing stencil shadow volume data for each pixel and a compressed stencil buffer is capable of storing stencil shadow volume data for a group of pixels. The compressed stencil buffer is utilized with a compressed stencil buffer cache to perform a stencil shadow volume operation more efficiently than present methods.