Apparatus and method for performing perspectively correct interpolation in computer graphics in a variable direction along a line of pixels
US5777623A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 15, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Feb 15, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In an apparatus and method for performing perspectively correct interpolation of texture coordinates in computer graphics, an incremental interpolation technique is used to calculate pixel values along a display line from an associated texture map. In order to evaluate divisions within the hyperbolic equations relating the texture coordinates to pixel position, the incremental technique performs a log subtraction in which the log of the fractional part of a number is looked-up, while the exponent part of the number is tracked separately. The differential of each texture coordinate is tracked. Further, the incremental technique is arranged so as to render the pixels either from left to right or from right to left depending upon which edge of the polygon being rendered is closer to the viewer and hence at which of the polygon edges accumulated errors will be most visible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.