TARGET INDEPENDENT RASTERIZATION

• US 20120086715A1
• Filed: 10/06/2010
• Published: 04/12/2012
• Est. Priority Date: 10/06/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: PATEL, AMAR, BOYD, CHARLES N., HINITZ, SHAI, PELTON, BLAKE D.
• Granted Patent: US 9,183,651 B2
• Time in Patent Office: Days
• US Class Current: 345/441
• CPC Class Codes: G06T 11/40 Filling a planar surface by adding surface attributes, e.g. colour or texture

Abstract

Methods, systems, and computer-storage media for target independent rasterization of an image. The target is the memory allocated for a rendered image within a graphics pipeline. Embodiments of the present invention allow the rasterization process'"'"'s sampling rate to be specified independently from the memory allocated for the rendered image. Embodiments of the present invention also allow the rasterization process to be executed at a rate that does not correspond to the memory allocated for the rendered target.

Claims

1. One or more computer-storage media having computer-executable instructions embodied thereon for performing a method of rendering antialiased two-dimensional graphics, the method comprising:

converting scene data into an input coverage mask by generating a set of geometric shapes tessellated from objects in the scene data;

generating a first instruction to define a render-target storage value in a graphics pipeline;

generating a second instruction to define a sampling rate for a rasterizer in the graphics pipeline, wherein the sampling rate is defined independently from the render-target storage value;

generating a third instruction to configure a pixel shader to process the input coverage mask through the graphics pipeline; and

communicating the input coverage mask to the graphics pipeline.

2. The media of claim 1, wherein the method further comprises receiving rendered scene data from the graphics pipeline.

3. The media of claim 1, wherein the method further comprises communicating the first instruction, the second instruction, and the third instruction to an application program interface that configures functions in a graphical processing unit.

4. The media of claim 1, wherein the render-target storage value is defined to be one times a screen size, and wherein the sampling rate is set to a value greater than 1 sub-pixel per pixel.

5. The media of claim 1, wherein, when there is no overlap between the set of geometric shapes, the pixel shader and an alpha blender are configured to count a number of bit sets in the input coverage mask, normalize results to a real number, and add the real number to current contents of a render target.

6. The media of claim 1, wherein, when there is overlap between the set of geometric shapes, the pixel shader and an alpha blender are configured to combine the input coverage mask with current contents of a render target using a logical process to determine which colors are added or subtracted from the render target.

7. The media of claim 6, wherein the logical process is one of a bitmap exclusive-or (XOR) operation and a bitmap OR operation.

8. The media of claim 1, wherein the render-target storage value is equivalent to one pixel per pixel in a rendered image and the sampling rate is set to 4 sub-pixels per pixel.

9. The media of claim 1, wherein the set of geometric shapes are triangles and the rasterizer is a triangle rasterizer.

10. A method of instructing a graphic processing unit to perform target independent rasterization, the method comprising:

receiving a first instruction to define a render-target storage value in a graphics pipeline running in a graphical processing unit;

allocating, through a computing device, an amount of memory in the graphical processing unit corresponding to the render-target storage value;

receiving a second instruction to define a sampling rate for a rasterizer in the graphics pipeline in the graphical processing unit, wherein the sampling rate is defined independently from the render-target storage value; and

configuring, through the computing device, the rasterizer to sample scene data at the sampling rate.

11. The method of claim 10, wherein the method further comprises configuring a pixel shader and an alpha blender to combine an input coverage mask with current contents of a render target using a logical process to determine which colors are added or subtracted from the render target.

12. The method of claim 11, wherein the logical process is one of a bitmap exclusive-or (XOR) operation and a bitmap OR operation.

13. The method of claim 10, wherein the method further comprises configuring a pixel shader and an alpha blender to count a number of bit sets in the input coverage mask, normalize results to a real number, and add the real number to current contents of a render target.

14. The method of claim 10, wherein the sampling rate is greater than the render-target storage value.

15. The method of claim 10, wherein the render-target storage value is equivalent to one pixel per pixel in a rendered image and the sampling rate is set to 4 sub-pixels per pixel.

16. The method of claim 10, wherein an image rendered by the graphics pipeline is a two-dimensional image.

17. A computer-readable storage medium storing an application program interface (API) for controlling a graphical processing unit (GPU), the API comprising:

a render-target storage property that defines an amount of memory allocated on the GPU to a rendered image; and

a sampling-rate property that defines a sampling rate used by a rasterizer component.

18. The media of claim 17, wherein the render-target storage property is independent of the sampling rate.

19. The media of claim 17, wherein the API is used to configure the GPU for rendering a two-dimensional image.

20. The media of claim 17, wherein the rasterizer component runs on the GPU.