System for emulating graphics operations

• US 8,040,353 B2
• Filed: 10/15/2010
• Issued: 10/18/2011
• Est. Priority Date: 04/16/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Harper, John
• Primary Examiner(s): Wu; Xiao M.
• Assistant Examiner(s): McDowell, Jr.; Maurice L
• Application Number:
  US12/905,360
• Publication Number:
  US 20110037768A1
• Time in Patent Office: 368 Days
• Field of Search: 345/522
• US Class Current: 345/522
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining

Abstract

Disclosed is a system for producing images including emulation techniques using multiple processors. The system provides for emulation of graphics processing resources such that a central processing unit may provide graphics support. Disclosed embodiments include emulation of selected graphics calls as well as emulation of a programmable graphics processor for compatibility with systems having no compatible GPU. Embodiments also include optimization of graphics code for a particular kind of processor.

Claims

1. A method of creating an image, the method comprising:

receiving a request to render a polygon comprising L pixels, the polygon represented by a programmable graphics processing unit (GPU) program, the programmable GPU program comprising a plurality of programmable GPU fragment programs, wherein the GPU program is represented as a plurality of nodes and a plurality of links, and wherein each of the plurality of nodes represents a programmable GPU fragment program and each of the plurality of links represents an intermediary result and storage necessary to hold the intermediary result;

converting the programmable GPU program into a central processing unit (CPU) program;

unrolling a loop in the CPU program such that the unrolled loop expresses N iterations of the loop; and

rendering the L pixels by executing, by a CPU, the unrolled loop L/N times.

2. The method of claim 1 wherein the act of rendering comprises performing texture lookups for each of the L pixels before rendering any of the L pixels.

3. The method of claim 1 further comprising:

dividing the polygon into sections;

selecting a first section for rendering; and

selecting a first scan line in the first section for rendering.

4. The method of claim 3 wherein the act of rendering comprises performing independent texture lookups for each of the pixels in the first scan line before rendering any of the pixels in the first scan line.

5. The method of claim 4 further comprising placing function calls in the CPU program for each dependent texture reference, the function calls performing a texture lookup during the act of rendering.

6. The method of claim 3 wherein the act of rendering comprises performing independent texture lookups for the first section before rendering any pixels in the first section.

7. The method of claim 6 further comprising placing function calls in the CPU program for each dependent texture reference, the function calls performing a texture lookup during the act of rendering.

8. The method of claim 3 further comprising placing function calls in the CPU program for each dependent texture reference, the function calls performing a texture lookup during the act of rendering.

9. The method of claim 3 further comprising storing each of the L rendered pixels in a buffer memory.

10. The method of claim 3 further comprising storing all of the rendered pixels from a single section in a common memory buffer.

11. The method of claim 1 further comprising placing function calls in the CPU program for each dependent texture reference, the function calls performing a texture lookup during the act of rendering.

12. The method of claim 1 further comprising storing each of the L rendered pixels in a buffer memory.

13. A non-transitory computer-readable medium having computer executable instructions stored thereon for performing the method recited in claim 1.

14. A method of creating an image, the method comprising:

receiving a request to render an image, the image comprising L pixels;

creating an object in a memory representing the image, the object comprising a programmable graphics processing unit (GPU) program, the programmable GPU program including one or more programmable GPU fragment programs, wherein the GPU program is represented as a plurality of nodes and a plurality of links, and wherein each of the plurality of nodes represents a programmable GPU fragment program and each of the plurality of links represents an intermediary result and storage necessary to hold the intermediary result;

compiling the programmable GPU program to generate a compiled program; and

rendering the image by executing the compiled program using a virtual machine under control of a central processing unit (CPU).

15. The method of claim 14 wherein the act of compiling comprises:

unrolling a loop in the GPU program such that the unrolled loop expresses N iterations of the loop;

performing independent texture lookups for each of the L pixels before rendering any of the L pixels; and

rendering the L pixels by executing the unrolled loop L/N times.

16. The method of claim 14 wherein the act of rendering further comprises:

creating one or more registers in a memory sufficient to store L pixels.

17. The method of claim 14 wherein the virtual machine accepts byte-code input.

18. The method of claim 14, wherein the compiled program is adapted for execution by a programmable GPU.

19. A non-transitory computer-readable medium having computer executable instructions stored thereon for performing the method recited in claim 14.