Systems and methods for updating a frame buffer based on arbitrary graphics calls

• US 20050012679A1
• Filed: 07/18/2003
• Published: 01/20/2005
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Karlov, Donald David
• Granted Patent: US 7,145,566 B2
• Time in Patent Office: Days
• US Class Current: 345/1.100
• CPC Class Codes: G09G 5/393 Arrangements for updating the contents of the bit-mapped memory

Abstract

A method for dividing a display into zones at system initialization for tracking which zones have any pixels revised so that, when the time comes to update the display, only the zones requiring revision (that is, those zones in which any pixel has been revised) are copied from shadow memory to the frame buffer for display on the display device. The memory for tracking these zones can be allocated at initialization and held since it is relatively small. Consequently, a significant performance gain may be achieved by avoiding the shortcomings of the existing methods in the art notwithstanding the fact that some “clean” pixels in each zone having even a single changed pixel are also rewritten to the frame buffer.

Claims

1. A method for updating the image on a computer display device, said method comprising:

logically dividing the computer display device into a plurality of zones;

tracking which zones are revised; and

updating only the revised zones on the display device.

2. The method of claim 1 wherein each zone of said plurality of zones is predefined.

3. The method of claim 1 wherein each zone of said plurality of zones has the same dimensions and number of pixels as the other zones.

4. The method of claim 1 wherein each zone of said plurality of zones is predefined and has the same dimensions and number of pixels as the other zones.

5. The method of claim 4 wherein the number of zones vertically aligned on the display device is equal to the number of zones horizontally aligned on the display device.

6. The method of claim 1 wherein the steps of logically dividing the computer display device into a plurality of zones, and tracking which zones are revised, are both performed by a graphical processing unit using a video random access memory.

7. The method of claim 1 wherein the steps of logically dividing the computer display device into a plurality of zones, and tracking which zones are revised, are both performed by a central processing unit using a system random access memory.

8. The method of claim 1 wherein the step of updating only the revised zones on the display device is performed by a graphical processing unit writing the revised zones from a video random access memory to a frame buffer.

9. The method of claim 1 wherein the step of updating only the revised zones on the display device is performed by a central processing unit writing the revised zones from a system random access memory directly to a frame buffer.

10. The method of claim 1 wherein the steps of logically dividing the computer display device into a plurality of zones and tracking which zones are revised are both performed by a graphical processing unit in a video random access memory;

and wherein the step of updating only the revised zones on the display device is performed by said graphical processing unit writing the revised zones from said video random access memory to a frame buffer.

11. The method of claim 1 wherein the steps of logically dividing the computer display device into a plurality of zones and tracking which zones are revised are both performed by a central processing unit in a system random access memory;

and wherein the step of updating only the revised zones on the display device is performed by said central processing unit writing the revised zones from said system random access memory directly to the frame buffer.

12. The method of claim 11 wherein said method is executed in conjunction with the use of a text-enhancement technology.

13. The method of claim 12 wherein said text-enhancement technology is a sub-pixel anti-aliaser.

14. The method of claim 1 wherein said method is executed in conjunction with the use of a text-enhancement technology.

15. The method of claim 14 wherein said text-enhancement technology is sub-pixel anti-aliaser.

16. The method of claim 1 wherein said method is executed on a computer system that favors a system-to-video flow of data traffic.

17. The method of claim 1 wherein system random access memory used for logically dividing the computer display device into a plurality of zones for tracking which zones are revised is allocated at startup.

18. A computer-readable medium having computer-readable instructions for updating the image on a computer display device, said computer-readable instructions comprising:

instructions for logically dividing the computer display device into a plurality of zones;

instructions for tracking which zones are revised; and

instructions for updating only the revised zones on the display device.

19. The computer-readable medium of claim 18 further comprising instructions for predefining a plurality of zones.

20. The computer-readable medium of claim 18 further comprising instructions for dividing the display into a plurality of zones each having the same dimensions and number of pixels.

21. The computer-readable medium of claim 18 further comprising instructions for predefining a plurality of zones and for dividing the display, wherein all zones in said plurality of zones each have the same dimensions and number of pixels.

22. The computer-readable medium of claim 21 further comprising instructions for dividing the display into a plurality of zones wherein the number of zones in said plurality of zones vertically aligned on the display device is equal to the number of zones in said plurality of zones horizontally aligned on the display device.

23. The computer-readable medium of claim 18 further comprising instructions for the graphical processing unit to logically divide the display device into a plurality of zones in video random access memory and thereafter track those zones in said plurality of zones that are revised.

24. The computer-readable medium of claim 18 further comprising instructions for the central processing unit to logically divide the display device into a plurality of zones in RAM and thereafter track those zones in said plurality of zones that are revised.

25. The computer-readable medium of claim 18 further comprising instructions for a graphical processing unit to update only a plurality of revised zones on a display device by writing the plurality of revised zones from a video random access memory to a frame buffer.

26. The computer-readable medium of claim 18 further comprising instructions for a central processing unit to update only a plurality of revised zones on a display device by writing the plurality of revised zones from a RAM to a frame buffer.

27. The computer-readable medium of claim 26 wherein said method is executed in conjunction with the use of a text-enhancement technology.

28. The computer-readable medium of claim 18 wherein said method is executed in conjunction with the use of a text-enhancement technology.

29. The computer-readable medium of claim 18 wherein said method is executed on a computer system that favors a system-to-video flow of data traffic.

30. The computer-readable medium of claim 18 wherein system random access memory used for logically dividing the computer display device into a plurality of zones for tracking which zones are revised is allocated at startup.

31. A system for updating the image on a computer display device, said system comprising:

a memory;

a shadow memory in said memory, said shadow memory comprising a plurality of zones;

a zone grid in said memory for tracking whether changes occur in each zone of said plurality of zones;

a processing unit for rendering revisions to said shadow memory and tracking in said zone grid which zones of said plurality of zones are revised;

a frame buffer to which the processing unit, based on the information stored in the zone grid, writes only those zones that have been revised from the shadow memory to said frame buffer; and

a display device coupled to said frame buffer.

32. The system of claim 31 wherein said processing unit is a central processing unit.

33. The system of claim 31 wherein said processing unit is a graphical processing unit.

34. The system of claim 31 wherein said memory is system random access memory.

35. The system of claim 31 wherein said processing unit is video random access memory.

36. A system for updating the image on a computer display device, said system comprising:

means for logically dividing the computer display device into a plurality of zones;

means for tracking which zones are revised; and

means for updating only the revised zones on the display device.