Graphics system shadow generation using a depth buffer
US5043922A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1989 |
| Grant date | Aug 27, 1991 |
| Priority date | — |
| Expiry date | Sep 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/10
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A shadow generation method and apparatus that employs a depth buffer technique to increase the speed of calculation of visible shadows. The system employs pipelined processors to determine visible objects and shadows generated by those objects for one or more light sources. The technique determines whether a shadow exists at a given pixel by evaluating the parity of the number of intersections between shadow polygons and a line of sight extending from the viewpoint. Pipeline processing is introduced to speed the process to result in rapid evaluation of a large number of objects and associated shadows. An alternate embodiment is presented which retains many of the speed advantages but allows the use of processors other than pipelined processors. Determination of the effect of a shadow on a given point is further speeded by indexing the shadow affect resulting in a quantized shadow correction value that reduces the processing requirements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.