US 8,553,041 B1 · 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.

Claims23

Dependent claims

A method for writing a tile to an A-Buffer, the method comprising:

receiving a first compressed write associated with a first target tile;
identifying a target stack within the A-buffer, wherein the A-buffer includes a plurality of stacks, each stack in the plurality of stacks includes one or more tiles where each tile has an associated index to identify the particular tile in the stack, and the target stack is included in the plurality of stacks;
identifying the first target tile within the target stack;
populating the first target tile with both:
compressed pixel data including sample data associated with N-by-M pixels that are proximally located in an image frame and that have a same per-sample rendering order index (PSROI), wherein N and M are positive integers, and
a set of tile compression bits that corresponds to the first compressed write;
determining that the target stack does not include any previously-written tiles;
and
updating an all-compressed bit to true to indicate that all tiles included in the target stack include compressed pixel data, wherein the all-compressed bit corresponds to the target stack.

6 more elements

A computer system, comprising:

a memory;
and
a graphics processing unit coupled to the memory and configured to write a tile to an A-Buffer, by:
receiving a first compressed write associated with a first target tile;
identifying a target stack within the A-buffer, wherein the A-buffer includes a plurality of stacks, each stack in the plurality of stacks includes one or more tiles where each tile has an associated index to identify the particular tile in the stack, and the target stack is included in the plurality of stacks;
identifying the first target tile within the target stack;
populating the first target tile with both:
compressed pixel data including sample data associated with N-by-M pixels that are proximally located and that have a same per-sample rendering order index (PSROI), wherein N and M are positive integers, and
a set of tile compression bits that corresponds to the first compressed write;
determining that the target stack does not include any previously-written tiles;
and
updating an all-compressed bit to true to indicate that all tiles included in the target stack include compressed pixel data, wherein the all-compressed bit corresponds to the target stack.

9 more elements

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims23