Multisampling dithering with shuffle tables
View Patent ↗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.
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.