Vertex order in a tessellation unit

Patent metadata

Field	Value
Publication number	US-9305397-B2
Application number	US-201213659675-A
Country	US
Kind code	B2
Filing date	Oct 24, 2012
Priority date	Oct 24, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Systems and methods for a tessellation are described. These systems and methods may divide the domain into a plurality of portions, including a first portion. The systems and methods may also determine coordinates for vertices for a first set of shapes that reside within the first portion, wherein each shape of the first set of shapes includes at least one vertex on a first edge of the first portion. After determining coordinates for the vertices for the first set of shapes, the systems and methods may determine coordinates for vertices for a second set of shapes that reside within the first portion. Each shape of the second set of shapes shares at least one vertex with at least one shape of the first set of shapes and none of the shapes of the second set of shapes includes a vertex on the first edge of the first portion.

First claim

What is claimed is:

1. A tessellation unit for tessellating a domain, the tessellation unit comprising circuitry, wherein the tessellation unit is configured to:
divide the domain into a plurality of portions, including a first portion;
divide at least the first portion into a plurality of sub-portions based on a number of shapes in the first portion and a size of a reuse buffer, such that storage of coordinates for a plurality of shapes within a first sub-portion of the sub-portions does not overflow the reuse buffer;
determine coordinates for vertices for a first set of shapes that reside within the first sub-portion, wherein each shape of the first set of shapes includes at least one vertex on a first edge of the first portion, wherein at least one shape of the first set of shapes includes at least one vertex on a boundary of the domain, and wherein the first edge of the first portion is not one of the boundaries of the domain; and
after determining coordinates for the vertices for the first set of shapes, determine coordinates for vertices for a second set of shapes that reside within the first sub-portion,
wherein a shape in the first set of shapes for which the tessellation unit determines coordinates last shares no vertex with a shape in the second set of shapes for which the tessellation unit determines coordinates first,
wherein each shape of the second set of shapes shares at least one vertex with at least one shape of the first set of shapes, and at least one shape of the second set of shapes includes at least one vertex on the same boundary of the domain as the at least one shape of the first set of shapes, and
wherein none of the shapes of the second set of shapes includes a vertex on the first edge of the first portion;
after determining coordinates for vertices for shapes in the first sub-portion, determine coordinates for vertices for a first set of shapes of a second sub-portion of the first portion wherein each shape of the first set of shapes of the second sub-portion includes at least one vertex on a first edge of the second sub-portion;
after determining coordinates for the vertices for the first set of shapes of the second sub-portion, determine coordinates for vertices for a second set of shapes of the second sub-portion,
wherein none of the shapes of the second set of shapes of the second sub-portion includes a vertex on the first edge of the second sub-portion; and
output the determined coordinates for the first set of shapes of the first sub-portion, the determined coordinates for the second set of shapes of the first sub-portion, the determined coordinates for first set of shapes of the second sub-portion, and the determined coordinates for second set of shapes of the second sub-portion for graphics processing.

2. The tessellation unit of claim 1 , where the domain is a triangular domain and wherein the domain is divided into three portions.

3. The tessellation unit of claim 1 , wherein the domain is a quad domain and wherein the domain is divided into four portions.

4. The tessellation unit of claim 1 , wherein the first edge of the first portion resides between two boundaries of the domain, wherein one of the two boundaries includes the boundary for the at least one shape of the first set of shapes of the first sub-portion that includes the at least one vertex on the boundary of the domain.

5. The tessellation unit of claim 1 , wherein the first portion comprises at least four edges and wherein a first edge and a second edge of the at least four edges reside within boundaries of the domain and wherein a third edge and a fourth edge of the four edges each reside on boundaries of the domain.

6. The tessellation unit of claim 1 , wherein, when the domain includes a side having an odd side length, the domain is split offset from a central axis of the side.

7. The tessellation unit of claim 1 , wherein to divide the domain, the tessellation unit is configured to divide the domain into at least one portion having a non-uniform tessellation factor relative to the first portion, and wherein the tessellation unit is further configured to determine coordinates for a vertex that reside within the portion having the non-uniform tessellation factor separately from determining coordinates for a vertex in the first portion.

8. The tessellation unit of claim 7 , wherein the at least one portion having a non-uniform tessellation factor relative to the first portion resides along a boundary of the domain.

9. A method of tessellating a domain comprising:
dividing, with a graphics processing unit (GPU), the domain into a plurality of portions, including a first portion;
dividing, with the GPU, at least the first portion into a plurality of sub-portions based on a number of shapes in the first portion and a size of a reuse buffer, such that storage of coordinates for a plurality of shapes within a first sub-portion of the sub-portions does not overflow the reuse buffer;
determining, with the GPU, coordinates for vertices for a first set of shapes that reside within the first sub-portion, wherein each shape of the first set of shapes includes at least one vertex on a first edge of the first portion, wherein at least one shape of the first set of shapes includes at least one vertex on a boundary of the domain, and wherein the first edge of the first portion is not one of the boundaries of the domain;
after determining coordinates for the vertices for the first set of shapes, determining, with the GPU, coordinates for vertices for a second set of shapes that reside within the first sub-portion,
wherein a shape in the first set of shapes for which the coordinates are determined last shares no vertex with a shape in the second set of shapes for which the coordinates are determined first,
wherein each shape of the second set of shapes shares at least one vertex with at least one shape of the first set of shapes, and at least one shape of the second set of shapes includes at least one vertex on the same boundary of the domain as the at least one shape of the first set of shapes, and
wherein none of the shapes of the second set of shapes includes a vertex on the first edge of the first portion;
after determining coordinates for vertices for shapes in the first sub-portion, determining, with the GPU, coordinates for vertices for a first set of shapes of a second sub-portion of the first portion, wherein each shape of the first set of shapes of the second sub-portion includes at least one vertex on a first edge of the second sub-portion;
after determining coordinates for the vertices for the first set of shapes of the second sub-portion, determining, with the GPU, coordinates for vertices for a second set of shapes of the second sub-portion,
wherein none of the shapes of the second set of shapes of the second sub-portion includes a vertex on the first edge of the second sub-portion;
adding, with the GPU, primitives to a patch based on the determined coordinates for vertices for the first set of shapes of the first sub-portion, and the determined coordinates for vertices for the second set of shapes of the first sub-portion, the determined coordinates for vertices for the first set of shapes of the second sub-portion, and the determined coordinates for vertices for the second set of shapes of the second sub-portion;
performing, with the GPU, graphics processing on the primitives of the patch to generate pixel values for pixels to be displayed; and
outputting, with the GPU, the pixel values.

10. The method of claim 9 , where the domain is a triangular domain and wherein the domain is divided into three portions.

11. The method of claim 9 , wherein the domain is a quad domain and where

Assignees

• Qualcomm Inc

Inventors

• Ceylan Usame
• Goel Vineet

Classifications

• G06T17/20 Primary

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