Method and apparatus for adaptive Phong shading
US5253339A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1990 |
| Grant date | Oct 12, 1993 |
| Priority date | — |
| Expiry date | Jul 26, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/83
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An adaptive shading method is utilized to generate shaded images in real time. The technique to shade the image is determined according to the curvature of the surface, the variation of the light vector across the surface, and the variation of the eye vector across the surface. The color or intensity is first computed at each of the vertices of the polygon. A series of tests are then performed to determine the order equation that is to be used to interpolate the color or intensity across the polygon between the vertices. Using this technique, polygons having a slight or no curvature and an infinite light source (thus being the simplest form of shading), will use an extremely fast, low order equation to interpolate across the polygon. Polygons, having a high degree of curvature and/or positional light source will utilize, as necessary, a higher order equation which requires additional computation time but produces desirable shading results.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.