System and method for structuring an a-buffer to support multi-sample anti-aliasing

Abstract

One embodiment of the present invention sets forth a technique for efficiently creating and accessing an A-Buffer that supports multi-sample compression techniques. The A-Buffer is organized in stacks of uniformly-sized tiles, wherein the tile size is selected to facilitate compression techniques. Each stack represents the samples included in a group of pixels. Each tile within a stack represents the set of sample data at a specific per-sample rendering order index that are associated with the group of pixels represented by the stack. Advantageously, each tile includes tile compression bits that enable the tile to maintain data using existing compression formats. As the A-Buffer is created, a corresponding stack compression buffer is also created. For each stack, the stack compression buffer includes a bit that indicates whether all of the tiles in the stack are similarly compressed and, consequently, whether the GPU may operate on the stack at an efficient per pixel granularity.