System for Emulating Graphics Operations

• US 20110037768A1
• Filed: 10/15/2010
• Published: 02/17/2011
• Est. Priority Date: 04/16/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Harper, John
• Granted Patent: US 8,040,353 B2
• Time in Patent Office: Days
• US Class Current: 345/502
• 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 having a plurality of pixels, the polygon represented by a programmable graphics processing unit (GPU) fragment program, the programmable GPU program comprising a plurality of programmable GPU fragment programs;

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

unrolling a loop in the CPU program such that the unrolled loop will process N of the plurality of pixels;

executing, by a CPU, the unrolled loop a variable number of times; and

rendering the N pixels in groups of L pixels, by executing, by the CPU, the unrolled loop L/N times.

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

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

6. 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.

7. 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.

8. 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.

9. The method of claim 5 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.

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

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

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

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

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

receiving a request to render an image, the image having a plurality of 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;

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).

14. The method of claim 13 wherein the act of compiling comprises:

unrolling a loop in the GPU program such that the unrolled loop will process N pixels of the plurality of pixels;

setting the unrolled loop to execute a variable amount of times;

performing independent texture lookups for each group of L pixels in the N pixels before processing any of the L pixels; and

rendering pixels in groups of L pixels, by executing the unrolled loop L/N times.

15. The method of claim 13 wherein the act of rendering comprises:

rendering the plurality of pixels in groups of L pixels; and

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

16. The method of claim 13 wherein the virtual machine accepts byte-code input.

17. The method of claim 13, wherein the compiled program is adapted for execution by a programmable GPU.

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