Method for computing parameters used in a non-homogeneous second order perspective texture mapping process using interpolation
US5841442A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1996 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Dec 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for computing input parameters used in a non-homogeneous second order perspective texture mapping process using interpolation. The present invention receives a polygon primitive (e.g., triangle) including screen display coordinates and texture map coordinates for each vertex (vmin, vmid, and vmax). Based on vertex information including perspective weights, w, screen display coordinates and texture map coordinates are determined for midpoints (i and j) of the two triangle slopes opposite the triangle's major slope. Based on a determined quadratic equation of the triangle's major slope, screen coordinates and texture map coordinates are determined at several selected points (e.g., imain, jmain, and midmain) along the major slope that corresponds to the i, j, and vmid points. From these values, quadratic coefficients a1, a2, and du.sub.-- ortho.sub.-- add are computed and also quadratic coefficients b1, b2 and dv.sub.-- ortho.sub.-- add are computed. The above values, parameters u.sub.-- main, du.sub.-- main (change in u over change in y), d2u.sub.-- main (change in .DELTA.u over change in .DELTA.y), du.sub.-- ortho (change in u over change in x), d2u.sub.-- ortho (change in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.