System and method for improved pixel rendering performance

• US 6,788,307 B2
• Filed: 04/09/2002
• Issued: 09/07/2004
• Est. Priority Date: 04/09/2002
• Status: Expired due to Fees

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Coleman, Terrence J., George, Ken
• Primary Examiner(s): Mancuso, Joseph
• Assistant Examiner(s): BRAUTIGAM, ALYSA N
• Application Number:
  US10/119,591
• Publication Number:
  US 20030189575A1
• Time in Patent Office: 882 Days
• Field of Search: 345/581, 345/582-618, 382/269
• US Class Current: 345/613
• CPC Class Codes: G06T 15/00 3D [Three Dimensional] image rendering
• CPC Class Codes: G09G 5/20 Function-generator circuits, e.g. circle generators line or curve smoothing circuits

Abstract

A device for improving pixel rendering performance in a computer graphics system. The device includes a pixel resolution buffer containing a plurality of pixel storage locations to store pixel values. A depth value is provided for each pixel storage location in the pixel resolution buffer, to store a closest depth for polygons that cover the pixel. A subpixel resolution buffer is also included with a least two subpixels corresponding to each pixel storage location in the pixel resolution buffer.

Claims

1. A device for improving pixel rendering performance in a computer graphics generation system, comprising:

a pixel resolution buffer, having a plurality of pixels to store pixel data for incoming polygon fragments and a pixel depth value for each pixel;

a polygon flag for each pixel in the pixel resolution buffer, where the flag indicates that the pixel contains one or multiple polygons;

a subpixel resolution buffer with at least two subpixels corresponding to each pixel in the pixel resolution buffer;

a processing module to determine whether an incoming fragment is closer than the stored pixel depth value and whether a given pixel is completely or partially covered by an incoming polygon fragment; and

a selection processor configured to evaluate the polygon flag and copy RGBA data from a graphics pipeline into affected subpixels.

2. A device as in claim 1 further comprising a selection processor configured to evaluate the polygon flag and write the incoming polygon fragment to at least one subpixel in the multi-sampling resolution buffer that corresponds to the pixel, if the polygon flag indicates that the pixel has multiple polygons.

3. A method for improving pixel rendering performance in a computer graphics generation system, comprising the steps of:

receiving a polygon fragment from a geometry subsystem;

determining whether a depth of the incoming polygon fragment is closer than a current depth of a current pixel;

determining whether a current pixel is completely covered or partially covered by the polygon fragment received;

identifying whether the current pixel contains one polygon;

selecting whether to write the polygon fragment to a pixel resolution buffer or a subpixel resolution buffer based on whether the current pixel is completely or partially covered by the polygon fragment;

writing the polygon fragment to the pixel resolution buffer if the pixel is covered by the polygon fragment or a subpixel resolution buffer if the pixel fragment is partially covered by the polygon fragment; and

copying RGBA data from the pixel resolution buffer to the subpixel buffers representing subpixels not touched by the polygon fragment received.

4. A method as in claim 3, further comprising the step of writing the incoming polygon fragment'"'"'s depth over the stored depth value if the incoming polygon fragment'"'"'s depth is closer than the stored depth value.

5. A method as in claim 3, wherein the subpixel resolution buffer includes two or more sub-samples for each pixel.

6. A method as in claim 3, wherein all the subpixel color values are filled when more than two polygons exist for the pixel.

7. A method as in claim 3, further comprising the step of setting polygon coverage flag to represent multiple polygons.

8. A method for improving pixel rendering performance in a computer graphics generation system, comprising the steps of:

receiving a polygon fragment from a geometry subsystem;

determining whether a depth of the incoming polygon fragment is closer than a current depth of a current pixel;

determining whether a current pixel is completely covered or partially covered by the polygon fragment received;

selecting whether to write the polygon fragment to a pixel resolution buffer or a subpixel resolution buffer based on whether the current pixel is completely or partially covered by the polygon fragment;

writing the polygon fragment to the pixel resolution buffer if the pixel is covered by the polygon fragment or a subpixel resolution buffer if the pixel fragment is partially covered by the polygon fragment; and

copying RGBA data from the pixel resolution buffer into the pixels not affected by the incoming polygon fragment.