SYSTEM, METHOD, AND COMPUTER PROGRAM PRODUCT FOR PERFORMING OBJECT-SPACE SHADING

• US 20160049000A1
• Filed: 03/11/2015
• Published: 02/18/2016
• Est. Priority Date: 08/12/2014
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: NVIDIA Corporation
• Inventors: Enderton, Eric B., Lum, Eric B., Wyman, Christopher Ryan, He, Yong, Fatahalian, Kayvon, Uralsky, Yury, Moreton, Henry Packard, Lefohn, Aaron Eliot, Patney, Anjul, Salvi, Marco, Zhang, Yubo, Hart, G. Evan Jr.
• Granted Patent: US 9,747,718 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: G06T 15/005 General purpose rendering architectures
• CPC Class Codes: G06T 15/80 Shading
• CPC Class Codes: G06T 17/205 Re-meshing
• CPC Class Codes: G06T 2210/36 Level of detail

Abstract

A system, method, and computer program product are provided for performing object-space shading. A primitive defined by vertices in three-dimensional (3D) space that is specific to an object defined by at least the primitive is received and a shading sample rate is computed for the primitive based on a screen-space derivative of coordinates of a pixel fragment transformed into the 3D space. A shader program is executed by a processing pipeline to compute shaded attributes for the primitive according to the computed shading sample rate.

Claims

1. A method comprising:

receiving a primitive defined by vertices in three-dimensional (3D) space that is specific to an object defined by at least the primitive;

computing a shading sample rate for the primitive based on a screen-space derivative of coordinates of a pixel fragment transformed into the 3D space that is specific to the object; and

executing, by a processing pipeline, a shader program to compute shaded attributes for the primitive according to the computed shading sample rate.

2. The method of claim 1, wherein the primitive is defined by a first vertex, a second vertex, and a third vertex in the 3D space.

3. The method of claim 2, further comprising:

executing, by the processing pipeline, the shader program to compute a first shaded attribute associated with the first vertex;

executing, by the processing pipeline, the shader program to compute a second shaded attribute associated with the second vertex; and

executing, by the processing pipeline, the shader program to compute a third shaded attribute associated with the third vertex.

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

5. The method of claim 4, wherein the interpolating comprises barycentric interpolation.

6. The method of claim 4, further comprising:

subdividing the primitive into multiple sub-primitives including a first sub-primitive defined by the third vertex, a fourth vertex, and a fifth vertex;

executing, by the processing pipeline, the shader program to compute a fourth shaded attribute associated with the fourth vertex; and

executing, by the processing pipeline, the shader program to compute a fifth shaded attribute associated with the fifth vertex.

7. The method of claim 6, further comprising computing a second shaded sample at a location within the first sub-primitive by interpolating the third, the fourth, and the fifth shaded attributes.

8. The method of claim 7, further comprising computing a final shaded sample for the primitive by interpolating the shaded sample and the second shaded sample.

9. The method of claim 1, wherein the primitive is subdivided into sub-primitives that approximate a size of the pixel fragment transformed into the 3D space.

10. The method of claim 9, wherein the primitive is subdivided based on the computed shading sample rate.

11. The method of claim 1, wherein the pixel fragment is a screen-space pixel.

12. The method of claim 1, further comprising, prior to receiving the primitive, determining that the primitive is visible during early z-testing.

13. The method of claim 1, further comprising:

receiving a second primitive defined by at least one additional vertex in the 3D space that is specific to the object defined by at least the primitive and the second primitive; and

computing a second shading sample rate for the second primitive, wherein the computed second shading sample rate is not equal to the computed shading sample rate for the primitive.

14. The method of claim 1, wherein the computed shading sample rate is also based on a specified shading rate corresponding to a number of samples specified for each screen-space pixel.

15. The method of claim 1, wherein a visibility rate at which z-testing is performed for the primitive is not equal to the computed shading sample rate.

16. The method of claim 1, wherein the coordinates of the pixel fragment are barycentric coordinates.

17. A system comprising:

a processing pipeline that is configured to;

receive a primitive defined by vertices in three-dimensional (3D) space that is specific to an object defined by at least the primitive;

compute a shading sample rate for the primitive based on a screen-space derivative of coordinates of a pixel fragment transformed into the 3D space that is specific to the object; and

execute a shader program to compute shaded attributes for the primitive according to the computed shading sample rate.

18. The system of claim 17, further comprising a memory that is coupled to the processing pipeline and configured to store the shaded attributes.

19. The system of claim 17, wherein the pixel fragment is a screen-space pixel.

20. A computer-readable storage medium storing instructions that, when executed by a processor, causes the processor to perform steps comprising:

receiving a primitive defined by vertices in three-dimensional (3D) space that is specific to an object defined by at least the primitive;

computing a shading sample rate for the primitive based on a screen-space derivative of coordinates of the vertices in the 3D space that is specific to the object; and

executing, by a processing pipeline, a shader program to compute shaded attributes for the primitive according to the computed shading sample rate.