Method and apparatus for providing polygon pixel sub-sample information using incremental means
US6057855A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 2, 1997 |
| Grant date | May 2, 2000 |
| Priority date | — |
| Expiry date | Jul 2, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2200/12
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for generating a mask identifying a number of subpixels that are covered by a primitive includes the process of apportioning an image, comprising a plurality of scan lines into a plurality of sub-scan lines, such that a number of sub-scan lines crosses each pixel. A sample point is placed on at least one of the sub-scan lines. To determine the number of samples that are covered by a primitive, edge stepping is used to step along each edge of the primitive, generating a sub-scan line coordinate for the edge. The edge stepping hardware is used for stepping either on a sub-scan line granularity, for operation in anti-aliased mode, or on a scan line granularity, for operation in aliased mode. In anti-aliased mode, as each edge sub-scan line coordinate is generated, it is compared against the coordinates of a sample point on that sub-scan line, to determine whether or not that sample point is covered by the primitive. A mask is generated for each pixel, with each bit of the mask corresponding to one of the sub-scan line samples. A bit in the mask is set if the subsample is covered by the primitive. Thus, a mask representing covered subsamples is provided by using …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.