Method and apparatus for generating non-homogenous fog
US6064392A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 16, 1998 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Mar 16, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T11/001
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention simulates the effect of non-homogenous fog in computer graphics images. The non-homogenous fog visibility equation includes four parameters. A distance scaling parameter K1. A variable fog parameter K2. A normalization constant K3, and a scaling constant K4. The visibility at a sample point can be determined using the visibility equation: ##EQU1## where Z.sub.ns is a normalized and scaled image distance which is equal to (K4*K1*Z)+(K4*K2). To improve computational efficiency the visibility function can be evaluated using a lookup table. The lookup table of the present invention has an efficient addressing scheme and a minimum number of output steps. The visibility function can be expressed as a function of a fog ratio and a fog distance. The fog distance is a distance from the viewpoint to the point where the visibility is reduced to 37% of full visibility. The fog ratio is the square root of the ratio of "near fog" density to "far fog" density. The visibility function expressed as a function of fog ratio and fog distance is ##EQU2##
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.