Gradient calculation system and method
US5719600A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 12, 1995 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Dec 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A gradient calculation system and method are described for use in a texture mapping system for calculating a gradient for each pixel defining a primitive of an image from a plane equation that describes the primitive. The primitive represented by the plane equation is decomposed into spans by an edge stepper, which steps the edges of the primitive, calculating the parameter values (e.g., S,T coordinates and perspective correction factor W) of the starting pixel for each span. A span stepper takes the starting parameter values generated by the edge stepper and interpolates parameter values for pixels along each span. The parameter values for each pixel are then passed to a gradient and perspective correction mechanism which calculates a gradient for each pixel by determining the difference between the parameter values for the current pixel and the parameter values of the next pixel in the x direction to derive .DELTA.Px and the adjacent pixel in the y direction to derive .DELTA.Py, and then taking the maximum differences as the gradient. In addition, perspective correction is performed by first modifying the primitive data defining the primitive with a perspective correction factor …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.