Alpha-to-coverage value determination using virtual samples
US8669999B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 2010 |
| Grant date | Mar 11, 2014 |
| Priority date | — |
| Expiry date | Aug 16, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2360/123
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
One embodiment of the present invention sets forth a technique for converting alpha values into pixel coverage masks. Geometric coverage is sampled at a number of “real” sample positions within each pixel. Color and depth values are computed for each of these real samples. Fragment alpha values are used to determine an alpha coverage mask for the real samples and additional “virtual” samples, in which the number of bits set in the mask bits is proportional to the alpha value. An alpha-to-coverage mode uses the virtual samples to increase the number of transparency levels for each pixel compared with using only real samples. The alpha-to-coverage mode may be used in conjunction with virtual coverage anti-aliasing to provide higher-quality transparency for rendering anti-aliased images.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.