Multisampling dithering with shuffle tables

• US 6,894,700 B2
• Filed: 02/25/2004
• Issued: 05/17/2005
• Est. Priority Date: 01/08/2002
• Status: Expired due to Term

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: 3DLabs Incorporated Limited (Creative Technology Ltd.)
• Inventors: Deming, James L., Kirkland, Dale L.
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): CUNNINGHAM, GREGORY F
• Application Number:
  US10/786,430
• Publication Number:
  US 20040164993A1
• Time in Patent Office: 447 Days
• Field of Search: 345/563, 345/592, 345/611, 345/626, 345/422, 345/768, 345/FOR.103, 345/113, 382/212, 382/213, 382/269, 382/283
• US Class Current: 345/611
• CPC Class Codes: G06T 11/40 Filling a planar surface by adding surface attributes, e.g. colour or texture
• CPC Class Codes: G06T 15/005 General purpose rendering architectures

Abstract

A system and method for generating random coverage masks for rendering images with transparent objects. The system uses shuffle tables for addresses of a pixel to index into a transparency table and to obtain a transparency mask, which is then ANDed with a coverage mask to obtain a new coverage mask.

Claims

1. A method for using random coverage masks for reducing visual artifacts while rendering transparent objects, said method comprising the steps of:

selecting a first index from a plurality of sources;

receiving a second index from a first shuffle table based on said first index;

obtaining a transparency mask from a transparency table based on said second index; and

generating a new coverage mask by combining said transparent mask with a coverage mask.

2. The method of claim 1, further comprising the steps of:

concatenating lower bits of X address and Y address of a pixel; and

selecting the concatenated lower bits for said first index.

3. A system for generating random coverage masks for use in rendering transparent objects, said system comprising:

first index selecting means for selecting a first index from a plurality of sources;

a shuffle table in communication with said first index selecting means, said shuffle table receiving said first index and outputting a second index;

a transparency table in communication with said shuffle table, said transparency table receiving said second index and generating a transparency mask; and

means for combining said transparency mask with a coverage mask and producing a random coverage mask, wherein said random coverage mask randomly enables samples of transparent objects.

4. The system of claim 3, wherein said first index selecting means further comprises a multiplexer and a selection logic.

5. The system of claim 3 further comprising means for adding two sources, one source being in communication with said shuffle table.