Graphics processing method and system for rendering items of geometry based on their size

Patent metadata

Field	Value
Publication number	US-12293448-B2
Application number	US-202318239402-A
Country	US
Kind code	B2
Filing date	Aug 29, 2023
Priority date	Feb 7, 2020
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

Methods and graphics processing systems render items of geometry using a rendering space which is subdivided into a plurality of first regions. Each of the first regions is sub-divided into a plurality of second regions. Each of a plurality of items of geometry is processed by identifying which of the first regions the item of geometry is present within, and for each identified first region determining an indication of the spatial coverage, within the identified first region, of the item of geometry, and using the determined indication of the spatial coverage within the identified first region to determine whether to add the item of geometry to a first control list for the identified first region or to add the item of geometry to one or more second control lists for a respective one or more of the second regions within the identified first region. Items of geometry within a second region can then be rendered using: (i) the first control list for the first region of which the second region is a part, and (ii) the second control list for the second region.

First claim

What is claimed is:

1. A method of rendering an item of geometry within a plurality of first regions of a rendering space, each of the first regions being subdivided into a plurality of second regions, the method comprising:
for each first region of the plurality of first regions,
based on a coverage of the item of geometry within the first region, selecting whether to add the item of geometry to a first control list for the first region or to one or more second control lists for a respective one or more second regions of the plurality of second regions; and
rendering the item of geometry using the first control list or the respective one or more second control lists.

2. The method of claim 1 , further comprising identifying each first region within which the item of geometry is present.

3. The method of claim 1 , further comprising, for each first region of the plurality of first regions, determining the coverage, within the first region, of the item of geometry.

4. The method of claim 3 , wherein determining the coverage, within the first region, of the item of geometry comprises determining a sub-polygon representing part of the item of geometry within the first region.

5. The method of claim 4 , further comprising:
determining a bounding box of the sub-polygon; and
comparing a size of the bounding box of the sub-polygon with a threshold size,
wherein if the size of the bounding box is below the threshold size then the item of geometry is added to the one or more second control lists.

6. The method of claim 5 , wherein if the size of the bounding box of the sub-polygon is above the threshold size then the method further comprises comparing the area of the sub-polygon with a threshold area, wherein if the area of the sub-polygon is below the threshold area then the item of geometry is added to the one or more second control lists, and wherein if the area of the sub-polygon is above the threshold area then the item of geometry is added to the first control list.

7. The method of claim 4 , wherein determining the coverage, within the first region, of the item of geometry further comprises:
determining the area of the sub-polygon; and
comparing the determined area of the sub-polygon with a threshold area, wherein if the area of the sub-polygon is below the threshold area then the item of geometry is added to the one or more second control lists, and wherein if the area of the sub-polygon is above the threshold area then the item of geometry is added to the first control list.

8. The method of claim 3 , wherein the area of the sub-polygon is determined using co-ordinates of the vertices of the sub-polygon which are rounded to quantised positions, wherein the quantised positions are aligned with boundaries between the second regions or with boundaries between blocks of second regions.

9. The method of claim 3 , wherein determining the coverage, within the first region, of the item of geometry comprises determining the number of second regions within the first region in which the item of geometry is present.

10. The method of claim 9 , wherein:
if the item of geometry is present within more than a threshold number of the second regions within the first region then the item of geometry is included in the first control list for the first region, and
if the item of geometry is present within less than the threshold number of the second regions within the first region then the item of geometry is included in the one or more second control lists for the respective one or more second regions within the first region in which the item of geometry is present.

11. The method of claim 9 , wherein:
if the item of geometry is present within all of the second regions within the first region then the item of geometry is included in the first control list for the first region, and
if the item of geometry is present within fewer than all of the second regions within the first region then the item of geometry is included in the one or more second control lists for the respective one or more second regions within the first region in which the item of geometry is present.

12. The method of claim 1 , wherein selecting whether to add the item of geometry to a first control list for the first region or to one or more second control lists for a respective one or more second regions of the plurality of second regions based on a coverage of the item of geometry within the first region comprises:
comparing the coverage with a threshold; and
using a result of the comparison to determine whether to add the item of geometry to the first control list or to the one or more second control lists.

13. A method of rendering a plurality of items of geometry comprising performing the method of claim 1 for each item of geometry in the plurality of items of geometry.

14. The method of claim 13 , wherein the plurality of items of geometry are rendered within a second region using (i) the first control list for the first region of which the second region is a part, and (ii) the second control list for the second region.

15. The method of claim 14 , wherein selecting whether to add the item of geometry to a first control list for the first region or to one or more second control lists for a respective one or more second regions of the plurality of second regions based on a coverage of the item of geometry within the first region comprises:
if the coverage indicates that the item of geometry fully covers the identified first region, adding the item of geometry to the first control list, and
if the coverage indicates that the item of geometry does not fully cover the identified first region, adding the item of geometry to the one or more second control lists for the respective one or more second regions within the identified first region in which the item of geometry is present,
wherein rendering the plurality of items of geometry within a second region comprises selectively processing items of geometry to determine which sample points within the second region are covered by the items of geometry, wherein said processing is skipped for items of geometry which are in the first control list since it is known that items of geometry in the first control list cover all of the sample points within the second region.

16. The method of claim 13 , wherein the plurality of items of geometry are stored in data blocks in accordance with a submission order of the items of geometry, wherein each data block is associated with a block ID, and wherein entries in the control lists include a block ID with a geometry indication to identify a data block and to indicate one or more items of geometry from the identified data block.

17. The method of claim 16 , wherein rendering the plurality of items of geometry within a second region comprises:
choosing, from the first control list for the first region of which the second region is a part and the second control list for the second region, the lowest block ID which has not been previously chosen; and
fetching one or more items of geometry from the data block with the chosen block ID in accordance with the geometry indication for said data block with the chosen block ID.

18. A method of rendering an item of geometry within a plurality of third regions of a rendering space, each of the third regions being subdivided into a plurality of first regions and each of the first regions being subdivided into a plurality of second regions, the method comprising:
for each third region of the plurality of third regions,
based on a coverage of the item of geometry within

Assignees

• Imagination Tech Ltd

Inventors

• Yang Xile
• Brigg Robert

Classifications

• G06T11/10

  Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77) · CPC title

• G06T17/20

  Finite element generation, e.g. wire-frame surface description, {tesselation} · CPC title

• G06T15/00 Primary

  Three-dimensional [3D] image rendering · CPC title

• G06T17/10

  Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes · CPC title

• G06T15/04

  Texture mapping · CPC title