Method and apparatus for displaying smooth-shaded objects
US5060172A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1989 |
| Grant date | Oct 22, 1991 |
| Priority date | — |
| Expiry date | Jul 6, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/80
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for rendering a smooth-shaded graphics primitive vertical series of horizontal pixel spans which extend between beginning and trailing edges of the primitive, the pixel locations being spaced from each other by selected distances dX and dY. The apparatus produces X and Y addresses of the first and last pixels in the beginning span of the primitive and the number of spans in the primitive. Also produced are step values (dX/dY) indicating the slopes of the beginning and trailing edges, and a beginning intensity value for the first pixel in the beginning span. DX is added to the X address of each pixel in each span to determine the X address of the next pixel in that span and one of the step values is added to the X address of the first pixel in each span to calculate the X address of the first pixel in the next span of the primitive. In addition, the other of the step values is added to the X address of the last pixel in each span of the primitive to calculate the X address of the last pixel in the next span of the primitive. The distance dY is added to the Y address of each span to calculate the Y address of the next span until the number of spans has been rende…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.