Method, system, and computer program product for modified blending between clip-map tiles

• US 6,373,482 B1
• Filed: 12/23/1998
• Issued: 04/16/2002
• Est. Priority Date: 12/23/1998
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Migdel, Christopher J., Hatch, Don Freeman
• Primary Examiner(s): Nguyen, Phu K.
• Application Number:
  US09/220,082
• Time in Patent Office: 1,210 Days
• Field of Search: 345/418, 345/419, 345/582, 345/583, 345/584, 345/587, 345/423, 345/424
• US Class Current: 345/419
• CPC Class Codes: G06T 15/04 Texture mapping

Abstract

A method, system, and computer program product for modifying blending between at least first and second clip-map tiles. Blending of a texel accessed in a modified blending region of the first clip-map tile is modified such that a blending profile between the first clip-map tile and a second clip-map tile is more smooth. Sharp transitions in blending between the first and second clip-map tiles are reduced or avoided. The magnitude of the modification of blending is a function of the location of the texel within the modified blending region. In one example, a determination is made on whether a texel to be accessed lies within a modified blending region within the first clip-map tile. A modified blending coefficient b is calculated when the texel to be accessed lies within the modified blending region.

Claims

1. A method for modifying blending between at least first and second clip-map tiles, comprising the steps of:

(a) determining whether a texel to be accessed lies within a modified blending region within the first clip-map tile; and

(b) determining a modified blending coefficient when the texel to be accessed lies within the modified blending region;

whereby, the modified blending coefficient can be used to smooth a blending profile between the first and second clip-map tiles.

2. The method of claim 1, wherein said determining step (a) comprises the steps of:

calculating a distance d between the texel being accessed and an edge of the first clip-map tile;

determining a blending distance D between a blend boundary of the modified blending region and the edge of the first clip-map tile; and

determining whether the calculated distance d is less than the blending distance D.

3. The method of claim 2, further comprising the step of setting the modified blending coefficient to zero when distance d is not less than blending distance D.

4. The method of claim 2, wherein said determining step (b) comprises the step of calculating a modified blending coefficient b that is a function of at least distance d.

5. The method of claim 4, wherein said modified blending coefficient b calculating step calculates b according to the following equation:

6. A system for modifying blending between at least first and second clip-map tiles, comprising:

(a) means for determining whether a texel to be accessed lies within a modified blending region within the first clip-map tile; and

(b) means for determining a modified blending coefficient when the texel to be accessed lies within the modified blending region;

whereby, the modified blending coefficient can be used to smooth a blending profile between the first and second clip-map tiles.

7. The system of claim 6, wherein said determining means (a) comprises:

means for calculating a distance d between the texel being accessed and an edge of the first clip-map tile;

means for determining a blending distance D between a blend boundary of the modified blending region and the edge of the first clip-map tile; and

means for determining whether the distance d is less than the blending distance D.

8. The system of claim 7, further comprising means for setting the modified blending coefficient to zero when distance d is not less than blending distance D.

9. The system of claim 7, wherein said determining means (b) comprises the step of calculating a modified blending coefficient b that is a function of at least distance d.

10. The system of claim 9, wherein said modified blending coefficient b calculating means calculates b according to the following equation:

11. A computer graphics system for providing texture from a texture pattern to an image to be rendered for display in real-time comprising:

a memory, said memory stores first and second clip-map tiles, wherein said first and second clip-map tiles include texels of a texture MIP-map representation of said texture pattern at different levels of detail; and

a modified blending module that modifies blending between said first and second clip-map tiles, wherein said modified blending module determines whether a texel to be accessed lies within a modified blending region of the first clip-map tile and determines a modified blending coefficient when the texel to be accessed lies within the modified blending region;

whereby, the modified blending coefficient can be used to smooth a blending profile between the first and second clip-map tiles.

12. The system of claim 11, wherein said memory stores texels including one-dimensional or multi-dimensional texel coordinate information.

13. A computer program product comprising a computer useable medium having computer program logic for enabling at least one processor in a computer system to modify blending between at least first and second clip-map tiles, said computer program logic comprising:

means for enabling the at least one processor to determine whether a texel to be accessed lies within a modified blending region of the first clip-map tile; and

means for enabling the at least one processor to determine a modified blending coefficient when the texel to be accessed lies within the modified blending region;

whereby, the modified blending coefficient can be used to smooth a blending profile between the first and second clip-map tiles.

14. A method for processing texture comprising the step of:

modifying blending of a texel accessed in a modified blending region of a first clip-map tile to provide a smoothed blending profile between the first clip-map tile and a second clip-map tile.

15. The method of claim 14, wherein said modifying blending step comprises the step of modifying the magnitude of blending as a function of the location of the texel within the modified blending region.

16. The method of claim 15, wherein said modifying blending step comprises the step of calculating a modified blending coefficient b that is a function of at least a distance d between the texel being accessed and an edge of the first clip-map tile.

17. The method of claim 16, wherein said modified blending coefficient b calculating step calculates b according to the following equation:

18. The method of claim 17, further comprising the step of calculating a new LOD available, the new LOD available comprising an integer part consisting of a level of detail and a fraction part consisting of said modified blending coefficient b.

19. The method of claim 15, wherein said modifying blending step comprises the step of calculating a modified blending coefficient b that is a non-linear function of at least a distance d between the texel being accessed and an edge of the first clip-map tile.