| 主权项 |
1. A method of compressing depth data in a tile-based graphics processing system that comprises:
a graphics processing pipeline comprising: a plurality of processing stages, including at least a rasteriser that rasterises input primitives to generate graphics fragments to be processed, each graphics fragment having one or more sampling points associated with it, and a renderer that processes fragments generated by the rasteriser to generate rendered fragment data; a tile buffer configured to store rendered fragment data locally to the graphics processing pipeline prior to that data being written out to an external memory, the tile buffer comprising an allocated amount of memory for use as a depth buffer that stores an array of depth values; and a write out stage configured to write data stored in the tile buffer to external memory; wherein the method comprises the write out stage when writing depth data from the tile buffer to memory: dividing each depth value to be compressed into plural parts; forming plural depth data channels, wherein each depth data channel is formed by associating corresponding ones of the plural parts of different depth values with each other; applying a data compression scheme separately to each depth data channel to be compressed in order to produce compressed representations of the depth data channels; and writing the compressed representations of the depth data channels to memory. |
