Method and apparatus for shading graphical images in a data processing system
US5659671A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1996 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Apr 25, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/506
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides an apparatus for displaying an image of an object, as illuminated by a light source, on a display within a computer graphics display system. The image is graphically represented by a mesh of polygons and each polygon within the mesh has a surface defined by a set of vertices. The vertices define the surface of the polygon. The apparatus includes a processor, such as a rasterizer, that is responsive to each set of vertices for rendering each surface within the mesh of polygons in response to ambient lighting to produce a number of initially rendered surfaces within the mesh of polygons. Phong shading is utilized by the present invention. The processor produces a specular highlight contribution for each surface within the mesh of polygons utilizing a halfway vector, pointing from each surface to a direction halfway between a light vector and a vector pointing towards a viewpoint, associated with a vector normal to each surface. Diffuse color contributions are generated within the processor using a light vector from a surface pointing to an illumination source associated with a vector normal to each surface. The specular highlight contribution and the di…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.