Apparatus and Method For Texture Level Of Detail Computation

• US 20130002651A1
• Filed: 12/21/2011
• Published: 01/03/2013
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Vivante Corporation (Verisilicon Microelectronics (Shanghai) Co. Ltd.)
• Original Assignee: Vivante Corporation (Verisilicon Microelectronics (Shanghai) Co. Ltd.)
• Inventors: Cai, Mike M., Allegrucci, Jean-Didier, Tai, Anthony Ya-Nai
• Granted Patent: US 8,487,948 B2
• Time in Patent Office: Days
• US Class Current: 345/419
• CPC Class Codes: G06T 15/04 Texture mapping

Abstract

A graphic processing system to compute a texture level of detail. An embodiment of the graphic processing system includes a memory device, a driver, and level of detail computation logic. The memory device is configured to implement a first lookup table. The first lookup table is configured to provide a first level of detail component. The driver is configured to calculate a log value of a second level of detail component. The level of detail computation logic is coupled to the memory device and the driver. The level of detail computation logic is configured to compute a level of detail for a texture mapping operation based on the first level of detail component from the lookup table and the second level of detail component from the driver. Embodiments of the graphic processing system facilitate a simple hardware implementation using operations other than multiplication, square, and square root operations.

Claims

1. A graphic processing system to compute a texture level of detail, the graphic processing system comprising:

a memory device to implement a first lookup table, the first lookup table to provide a first level of detail component;

a driver to calculate a log value of a second level of detail component;

level of detail computation logic coupled to the memory device and the driver, the level of detail computation logic to compute a level of detail for a texture mapping operation based on the first level of detail component from the lookup table and the second level of detail component from the driver.

2. The graphic processing system of claim 1, the level of detail computation logic further configured to compute the level of detail using arithmetic operations other than a multiplication operation.

3. The graphic processing system of claim 1, the level of detail computation logic further configured to compute the level of detail using arithmetic operations other than square and square root operations.

4. The graphic processing system of claim 1, further comprising a hardware implementation of the level of detail computation logic.

5. The graphic processing system of claim 1, the level of detail computation logic further configured to determine a maximum value of a first log term and a second log term, the first log term corresponding to a width dimension of a texture map, and the second log term corresponding to a height dimension of the texture map.

6. The graphic processing system of claim 1, the memory device further configured to implement a second lookup table, the first lookup table comprising a log lookup table to provide log values of the first level of detail component, and the second lookup table comprising a function lookup table to provide values of a function component of the level of detail computation.

7. The graphic processing system of claim 6, the level of detail computation comprising a two-dimensional level of detail computation, the function component of the level of detail computation defined by the following equation:

f(x)=0.5.times.log(1+2.sup.(2x)), where x=log(dtdx)−

log(dsdx)+log(height)−

log(width).

8. The graphic processing system of claim 6, the level of detail computation comprising a three-dimensional level of detail computation.

9. The graphic processing system of claim 6, further comprising a software module coupled to the driver, the software module to provide a dimension value to the driver, the second level of detail component comprising a log value of the dimension value.

10. The graphic processing system of claim 9, the dimension value corresponding to a width, a height, or a depth.

11. A method for computing a texture level of detail, the method comprising:

computing a first log term based on a first plurality of level of detail components, the first log term corresponding to a first dimension of a texture map, the first plurality of level of detail components generated with lookup and arithmetic operations other than multiplication;

computing a second log term based on a second plurality of level of detail components, the second log term corresponding to a second dimension of a texture map, the second plurality of level of detail components generated with lookup and arithmetic operations other than multiplication; and

computing the level of detail according to a maximum of the first and second log terms.

12. The method of claim 11, further comprising looking up a first level of detail component of the first log term from a log lookup table.

13. The method of claim 12, further comprising obtaining a second level of detail component of the first log term from a driver, the driver receiving a dimension value from software.

14. The method of claim 13, further comprising looking up a third level of detail component of the first log term from a function lookup table, the third level of detail component comprising a function component.

15. The method of claim 14, further comprising generating a sum of the first, second, and third level of detail components to compute the first log term.

16. The method of claim 11, the arithmetic operations comprising operations other than square and square root operations.

17. The method of claim 16, the first and second log terms comprising:

L.sub.1=log(dsdx)+log(width)+f(x), and L.sub.2=log(dsdy)+log(width)+f(y), where L.sub.1 designates the first log term, f(x) designates a first function component, L.sub.2 designates the second log term, and f(y) designates a second function component.

18. An apparatus for computing a texture level of detail, the apparatus comprising:

means for computing first and second log terms using operations other than multiplication, square, and square root operations; and

means for computing the texture level of detail based on the first and second log terms.

19. The apparatus of claim 18, the means for computing the first and second log terms further configured for computing the first and second log terms using only lookup operations and integer math operations.

20. The apparatus of claim 18, further comprising:

means for implementing a first plurality of log lookup values for the first log term;

means for implementing a first plurality of function lookup values for the first log term;

means for implementing a second plurality of log lookup values for the second log term; and

means for implementing a second plurality of function lookup values for the second log term.