System, method, and computer program product for shading using a dynamic object-space grid

Patent metadata

Field	Value
Publication number	US-9754407-B2
Application number	US-201514645327-A
Country	US
Kind code	B2
Filing date	Mar 11, 2015
Priority date	Aug 12, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A system, method, and computer program product are provided for shading using a dynamic object-space grid. An object defined by triangle primitives in a three-dimensional (3D) space that is specific to the object is received and an object-space shading grid is defined for a first triangle primitive of the triangle primitives based on coordinates of the first triangle primitive in the 3D space. A shader program is executed by a processing pipeline to compute a shaded value at a point on the object-space shading grid for the first triangle primitive.

First claim

What is claimed is:

1. A method comprising:
receiving an object defined by a plurality of triangle primitives in a three-dimensional (3D) space that is specific to the object;
defining an object-space shading grid for at least one of the plurality of triangle primitives based on coordinates at vertices of the at least one triangle primitive in the 3D space,
wherein a shape of an object-space shading element corresponds to a shape of the at least one triangle primitive, wherein the object-space shading grid comprises at least one object-space shading element; and
executing, by a processing pipeline, a shader program to compute a shaded value at a point on the object-space shading grid for a first triangle primitive.

2. The method of claim 1 , wherein the vertices comprise a first vertex, a second vertex, and a third vertex that define the first triangle primitive and the point corresponds to the first vertex.

3. The method of claim 2 , further comprising:
executing, by the processing pipeline, the shader program to compute a second shaded value at a second point that corresponds to the second vertex; and
executing, by the processing pipeline, the shader program to compute a third shaded value at a third point that corresponds to the third vertex.

4. The method of claim 3 , further comprising computing a shaded sample at a location within the first triangle by interpolating the first, second, and third shaded values.

5. The method of claim 1 , wherein the object-space shading grid comprises an additional level comprising only vertex positions of four sub-triangles produced by bisecting each edge of the first triangle primitive.

6. The method of claim 5 , wherein the additional level of the object-space shading grid is dynamically generated during execution of the shader program.

7. The method of claim 1 , wherein the object-space shading grid is mipmapped such that each higher resolution mip level is generated by subdividing a lower resolution mip level into substantially congruent sub-triangles within the first triangle primitive.

8. The method of claim 7 , further comprising:
transforming a screen-space pixel into the 3D space that is specific to the object to generate a footprint; and
identifying a first mip level of the mipmapped object-space shading grid that includes a sub-triangle having an area that most closely approximates an area of the footprint.

9. The method of claim 8 , further comprising identifying a second mip level of the mipmapped object-space shading grid that includes a sub-triangle having an area that closely approximates the area of the footprint.

10. The method of claim 9 , further comprising executing the shader program to compute a second shaded value at a second point on the object-space shading grid for the sub-triangle.

11. The method of claim 10 , wherein the sub-triangle is defined by the point, the second point on the object-space shading grid, and a third point on the object-space shading grid.

12. The method of claim 11 , further comprising:
executing the shader program to compute a third shaded value at the third point for the sub-triangle; and
computing a shaded sample at a sample location within the sub-triangle based on the shaded value, the second shaded value, and the third shaded value.

13. The method of claim 1 , further comprising:
transforming a screen-space pixel into the 3D space that is specific to the object to generate a footprint defined by at least a first sample location; and
determining that a sub-triangle within the first triangle encloses the first sample location.

14. The method of claim 13 , further comprising, executing the shader program to compute a second shaded value at a second point on the object-space shading grid that corresponds to a first vertex of the sub-triangle.

15. The method of claim 1 , further comprising updating the object-space grid in response to a change in a shape of the first triangle primitive.

16. The method of claim 1 , further comprising computing a dynamic shading rate for the first triangle primitive that varies within the first triangle primitive and is used to sample the object-space shading grid for the first triangle primitive.

17. A system comprising:
a processing pipeline that is configured to:
receive an object defined by a plurality of triangle primitives in a three-dimensional (3D) space that is specific to the object;
define an object-space shading grid for at least one of the plurality of triangle primitives based on coordinates at vertices of the at least one triangle primitive in the 3D space,
wherein a shape of an object-space shading element corresponds to a shape of the at least one triangle primitive, wherein the object-space shading grid comprises at least one object-space shading element; and
execute a shader program to compute a shaded value at a point on the object-space shading grid for a first triangle primitive.

18. The system of claim 17 , wherein the object-space shading grid is mipmapped such that each higher resolution mip level is generated by subdividing a lower resolution mip level into substantially congruent sub-triangles within the first triangle primitive.

19. The system of claim 17 , wherein the object-space shading grid comprises an additional level comprising only vertex positions of four sub-triangles produced by bisecting each edge of the first triangle primitive.

20. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, causes the processor to perform steps comprising:
receiving an object defined by a plurality of triangle primitives in a three-dimensional (3D) space that is specific to the object;
defining an object-space shading grid for at least one of the plurality of triangle primitives based on coordinates at vertices of the at least one triangle primitive in the 3D space,
wherein a shape of an object-space shading element corresponds to a shape of the at least one triangle primitive, wherein the object-space shading grid comprises at least one object-space shading element; and
executing, by a processing pipeline, a shader program to compute a shaded value at a point on the object-space shading grid for a first triangle primitive.

Assignees

• Nvidia Corp

Inventors

• Patney Anjul
• Enderton Eric B
• Lum Eric B
• Salvi Marco
• Wyman Christopher Ryan
• Zhang Yubo
• He Yong
• Hart Jr G Evan
• Fatahalian Kayvon
• Uralsky Yury
• Moreton Henry Packard
• Lefohn Aaron Eliot

Classifications

• G06T15/80 Primary

  Shading · CPC title

• G06T17/205

  Re-meshing · CPC title

• G06T2210/36

  Level of detail · CPC title

• G06T17/10

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

• G06T17/20

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