Method and apparatus for rendering shadows
US7023438B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 2003 |
| Grant date | Apr 4, 2006 |
| Priority date | — |
| Expiry date | Oct 14, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/60
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for rendering shadows. A pre-rendering process implements a two dimensional array or map of depth-based functions, such as a visibility function in z. During rendering of an object scene, these functions are accessed via lookup operations to efficiently determine the function value for a sample point at a given depth. The use of visibility functions allows for partial light attenuation effects. Each visibility function is computed by filtering multiple transmittance functions obtained by casting sample rays from a light source onto an object scene. The visibility function is implemented as a sequence of vertices. Colored shadows are modeled by vertices comprising a depth value and separate visibility function values for red, green, and blue light at a given depth value. Compression is achieved by minimizing the number of vertices needed to represent a visibility function within a desired error tolerance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.