Compression and decompression of sub-primitive presence indications for use in a rendering system

Patent metadata

Field	Value
Publication number	US-12462437-B2
Application number	US-202318202990-A
Country	US
Kind code	B2
Filing date	May 29, 2023
Priority date	May 30, 2022
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

Compressed data is decompressed to determine sub-primitive presence indications in a rendering system. A received compressed block of sub-primitive presence indications is subdivided into a plurality of parent regions, each subdivided into a plurality of child regions. A hierarchical representation of the block of sub-primitive presence indications is provided, wherein: (i) for each parent region whose child regions all have the same presence state, parent-level data is included to represent the presence state of the parent region without child-level data for the child regions within the parent region being included in the hierarchical representation, and (ii) for each parent region whose child regions do not all have the same presence state, child-level data for the child regions within the parent region is included in the hierarchical representation to represent the presence states for the child regions within the parent region. If child-level data is included in the hierarchical representation, child-level data for said one of the parent regions is used to determine one or more sub-primitive presence indications in the parent region. If child-level data is not included in the hierarchical representation, parent-level data is used, without child-level data, to determine one or more sub-primitive presence indications in the parent region.

First claim

What is claimed is:

1 . A method of decompressing compressed data to determine one or more sub-primitive presence indications for use in a rendering system, the method comprising:
receiving a block of compressed data for a block of sub-primitive presence indications, wherein the block of sub-primitive presence indications is subdivided into a plurality of parent regions, each of the parent regions being subdivided into a plurality of child regions, wherein the block of compressed data comprises a hierarchical representation of the block of sub-primitive presence indications, wherein: (i) for each of one or more parent regions whose child regions all have the same presence state, parent-level data is included in the hierarchical representation to represent the presence state of the parent region without child-level data for the child regions within the parent region being included in the hierarchical representation, and (ii) for each of one or more parent regions whose child regions do not all have the same presence state, child-level data for the child regions within the parent region is included in the hierarchical representation to represent the presence states for the child regions within the parent region; determining whether child-level data is included in the hierarchical representation for one of the parent regions; if it is determined that child-level data is included in the hierarchical representation for said one of the parent regions, using child-level data for said one of the parent regions to determine one or more sub-primitive presence indications in said one of the parent regions; and if it is determined that child-level data is not included in the hierarchical representation for said one of the parent regions, using parent-level data for said one of the parent regions, without child-level data, to determine one or more sub-primitive presence indications in said one of the parent regions.

2 . The method of claim 1 , further comprising reading parent-level data for said one of the parent regions from the block of compressed data, wherein the read parent-level data is used to determine whether child-level data is included in the hierarchical representation for said one of the parent regions.

3 . The method of claim 1 , wherein each of the child regions corresponds with a respective one of the sub-primitive presence indications in the block of sub-primitive presence indications.

4 . The method of claim 1 , wherein each of the presence indications in the block of sub-primitive presence indications indicates a presence state which is one of: (i) fully present, (ii) fully absent, and (iii) partially present.

5 . The method of claim 4 , wherein parent-level data representing a presence state of a parent region indicates:
(i) that all of the child regions within the parent region are fully present, (ii) that all of the child regions within the parent region are fully absent, (iii) that all of the child regions within the parent region are partially present, or (iv) that the child regions within the parent region have a mix of presence states, wherein for parent-level data representing a presence state of a parent region indicating (i), (ii) or (iii), it is determined that child-level data is not included in the hierarchical representation for the parent region, and wherein for parent-level data representing a presence state of a parent region indicating (iv), it is determined that child-level data is included in the hierarchical representation for the parent region.

6 . The method of claim 4 , wherein child-level data representing a presence state of a child region indicates that:
(i) the child region is fully present, (ii) the child region is fully absent, or (iii) the child region is partially present.

7 . The method of claim 1 , wherein each of the parent regions has four child regions within it, and wherein the method further comprises, for each of the one or more parent regions whose child regions do not all have the same presence state, three of the child regions within the parent region have the same presence state as each other, wherein it is determined that child-level data is included in the hierarchical representation for said one of the parent regions, and wherein said using the child-level data for said one of the parent regions to determine one or more sub-primitive presence indications in said one of the parent regions comprises:
reading a palette indication from the child-level data for said one of the parent regions which indicates that one of:
(i) a majority of the four child regions in said one of the parent regions have a partially present presence state and a minority of the four child regions in said one of the parent regions have a fully present presence state,
(ii) a majority of the four child regions in said one of the parent regions have a partially present presence state and a minority of the four child regions in said one of the parent regions have a fully absent presence state,
(iii) a majority of the four child regions in said one of the parent regions have a fully present presence state and a minority of the four child regions in said one of the parent regions have a partially present presence state, and
(iv) a majority of the four child regions in said one of the parent regions have a fully absent presence state and a minority of the four child regions in said one of the parent regions have a partially present presence state; and

reading a minority position indication from the child-level data for said one of the parent regions which indicates the position of said minority of the four child regions within the parent region; and
using the read palette indication and the read minority position indication to determine the one or more sub-primitive presence indications in said one of the parent regions.

8 . The method of claim 1 , wherein the block of sub-primitive presence indications is subdivided into a plurality of grandparent regions, wherein each of the grandparent regions is subdivided into a respective plurality of the parent regions.

9 . The method of claim 8 , wherein for each of one or more grandparent regions whose parent regions all have child regions within them which all have the same presence state, grandparent-level data is included in the hierarchical representation to represent the presence state of the grandparent region without parent-level data or child-level data for the parent regions or child regions within the grandparent region being included in the hierarchical representation, wherein the method further comprises:
determining whether parent-level data is included in the hierarchical representation for one of the grandparent regions; if it is determined that parent-level data is included in the hierarchical representation for said one of the grandparent regions, using the parent-level data for said one of the grandparent regions to determine one or more sub-primitive presence indications in said one of the grandparent regions; and if it is determined that parent-level data is not included in the hierarchical representation for said one of the grandparent regions, using grandparent-level data for said one of the grandparent regions, without parent-level data, to determine one or more sub-primitive presence indications in said one of the grandparent regions.

10 . The method of claim 9 , further comprising reading grandparent-level data for said one of the grandparent regions from the block of compressed data, wherein the read grandparent-level data is used to determine whether parent-level data is included in the hierarchical representation for said one of the grandparent regions.

11 . The method o

Assignees

• Imagination Tech Ltd

Inventors

• Ozkan Alper
• Fenney Simon

Classifications

• G06T2210/21

  Collision detection, intersection · CPC title

• G06T15/06

  Ray-tracing · CPC title

• G06T9/00

  Image coding (bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00) · CPC title

• G06T9/40 Primary

  Tree coding, e.g. quadtree, octree · CPC title

• G06T9/001 Primary

  Model-based coding, e.g. wire frame · CPC title