Patent ID: 11880933
Assignee: IMAGINATION TECHNOLOGIES LIMITED
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 17:
18. A method of performing hidden surface removal processing on primitive fragments in a graphics processing system in which a rendering space is subdivided into a plurality of tiles and each tile comprises a plurality of pixel samples, the method comprising:
receiving a primitive fragment of a set of primitive fragments associated with a tile of the plurality of tiles, the primitive fragment corresponding to a pixel sample of the tile;
receiving information indicating whether the primitive fragment requires a depth buffer read for full resolution depth testing;
if the primitive fragment is a first primitive fragment in the set, initializing a current best depth value buffer for the tile and a depth value update map for the tile, wherein the current best depth value buffer for the tile comprises a depth value for each pixel sample of the tile, the depth value update map indicates which depth values of the current best depth value buffer have been updated, and the depth value update map is initialized to indicate that no depth values in the current best depth value buffer have been updated;
determining whether the primitive fragment has a best depth value for the pixel sample corresponding to the primitive fragment according to a depth compare mode; and
in response to determining that the primitive fragment has the best depth value for the pixel sample corresponding to the primitive fragment, updating the depth value for that pixel sample in the current best depth value buffer with the depth of the primitive fragment, and updating the depth value update map to indicate that the depth value for that pixel sample has been updated;
wherein, when the first primitive fragment does not require a depth buffer read, initializing the current best depth value buffer comprises initializing each depth value in the current best depth value buffer to a worst depth value according to the depth compare mode, and, when the first primitive fragment requires a depth buffer read, initializing the current best depth value buffer comprises initializing each depth value in the current best depth value buffer to a corresponding depth value in the depth buffer for the tile.