System and method for adaptive z-buffer compression in low power GPUS and improved memory operations with performance tracking

摘要

Z-buffer compression may be useful for reducing memory usage bandwidth and for performance optimizations. A trackable method of doing the same may be additionally advantageous, as a lossy z-buffer compression scheme may noticeably alter a displayed object. A z-buffer compression unit receives an uncompressed tile, including a matrix of fragments, each representing a pixel and including a z-value. A minimum and maximum z-values of the tile are determined, and a comparison between each z-value of the tile to the minimum/maximum z-value generates a difference value. Basic tile information is then stored, and a compressed tile is stored in the z-buffer memory if the difference value is below a first threshold, such that each fragment is represented by a difference value and an indicator bit, to indicate if the difference is from the minimum z-value or the maximum z-value. The basic tile information includes the minimum z-value, and the maximum z-value.