Christopher R Shaw

US Patent:

61219746, Sep 19, 2000

Filed:

Jun 27, 1996

Appl. No.:

8/670299

Inventors:

Christopher William Shaw - Austin TX

Assignee:

Cirrus Logic, Inc. - Fremont CA

International Classification:

G06T 1100

US Classification:

345430

Abstract:

A process and implementing computer system for graphics applications in which information files such as texture maps (TMs) are prioritized and stored in a relatively fast local memory. The method of prioritization includes initially sorting the information files by order of the frequency with which corresponding graphics primitive elements are called by the application. The priority is adjusted such that the smaller TMs get an increase in their priority so that more TMs may be placed in faster graphics memory. Thereafter among similarly prioritized groups of information files, the larger of the files are first stored in the fast local memory and the remaining files are marked for storage in the system memory after the fast local memory has been fully utilized. A searching routine enables an identification of available or free storage space in the local memory and the method further compares individual texture map files with available free memory space to optimize storage of the texture maps on a priority basis to the fast local memory.

US Patent:

60549939, Apr 25, 2000

Filed:

Sep 17, 1997

Appl. No.:

8/932402

Inventors:

Goran Devic - Austin TX
Christopher Shaw - Pflugerville TX

Assignee:

Cirrus Logic, Inc. - Fremont CA

International Classification:

G06T 740

US Classification:

345426

Abstract:

A graphics system includes a graphics controller for rendering polygons with specular highlighting (glare) based on a comparison of texel color values from a texture map to a range of color values. The graphics processor includes range registers for storing the range of color values and color comparators for comparing a texel color value to the range of colors stored in the range registers. The range of color values used in the comparison corresponds to the range of colors of those portions of a texture for which specular highlighting is appropriate, such as metallic surfaces off which light reflects. If a texel color value to be applied to a screen pixel is within the range of colors defined for specular highlighting, the graphics processor adds an appropriate specular component to the texel value.

US Patent:

61813478, Jan 30, 2001

Filed:

Sep 17, 1997

Appl. No.:

8/932760

Inventors:

Goran Devic - Austin TX
Christopher Shaw - Pflugerville TX

Assignee:

Cirrus Logic, Inc. - Fremont CA

International Classification:

G06T 1140

US Classification:

345430

Abstract:

A graphics system including a selectable mode smoothing filter for improved texture mapping. An x, y pixel coordinate is mapped into a u, v texture map. The mapped u, v coordinate includes integer and fractional portions. Depending on the location of the coordinate relative to the four nearest texels, which are represented as integers, one of several texture mapping schemes are used to either select or calculate the texel value to be used to render the pixel at the x, y screen location. The three texture mapping schemes include point sampling in which the nearest texel from the texture map is selected, two-texel averaging in which the closest two texels are combined in a weighted average, and four-texel averaging in which the closest four texels are combined in a weighted average. Scale factors in the range of 0 to 1 are computed for averaging texel values together. By including the complete range of 0 to 1, the scale factors permit greater control over the averaging process and accordingly, images with high spatial frequency content are not distorted as much as in previous graphics systems.

US Patent:

6184893, Feb 6, 2001

Filed:

Jan 8, 1998

Appl. No.:

9/004483

Inventors:

Goran Devic - Austin TX
Christopher W. Shaw - Pflugerville TX

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

G06T 1140

US Classification:

345430

Abstract:

A method and system for filtering texture map data for improved image quality in a graphics computer system. The present invention is directed to a method and system for performing texture map filtering for reducing "flickering" and "sparkling" when rendering a relatively small graphics primitives using a texel map of relatively larger area and low color frequency. A footprint area is defined as the area of texel map space that is mapped into one pixel coordinate of display space. One embodiment of the present invention is particularly useful in texture mapping where the footprint area is larger than one. In this instance, during rendering, the change in texel map coordinates (e. g. , du, dv) is large for a unit change in screen coordinates (e. g. , dx, dy). When obtaining a texel at location (u, v), the present invention performs a color filtering of texels located at distances du and dv away from the texel at location (u, v).

US Patent:

63269759, Dec 4, 2001

Filed:

Jun 22, 1998

Appl. No.:

9/102612

Inventors:

Christopher William Shaw - Austin TX

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

G06T 1140

US Classification:

345582

Abstract:

A process and implementing computer system for graphics applications in which information files such as texture maps (TMs) are prioritized and stored in a local relatively fast RDRAM memory. The method of prioritization includes initially sorting the information files by order of the frequency with which corresponding graphics primitive elements are called by the application. The priority is adjusted such that the smaller TMs get an increase in their priority so that more TMs may be placed in faster graphics memory. Thereafter among similarly prioritized groups of information files, the larger of the files are first stored in the fast graphics memory and the remaining files are marked for storage in the system memory after the fast local memory has been fully utilized. A searching routine enables an identification of available or free storage space in the local memory and the method further compares individual texture map files with available free memory space to optimize storage of the texture maps on a priority basis to the fast local graphics memory.