Apparatus for fixed-point graphics and method therefor
US6559856B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1999 |
| Grant date | May 6, 2003 |
| Priority date | — |
| Expiry date | Sep 9, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/24
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Lighting parameters are received as floating-point numbers from a software application via an application programming interface (API). The floating-point numbers are converted to a fixed-point representation having a preselected number of bits. The number of bits is selected in accordance with a predetermined number of bits required by a frame buffer, which thus establishes the number of color values supported by the graphics display system. In order to preserve accuracy to within the number of bits in each value in the frame buffer, the representation in the fixed-point engine includes additional bits relative to the number of bits in the color values sent to the frame buffer. Floating-point values received via the graphics API are converted to fixed-point representations by first prescaling the floating-point values. The fixed-point operations generate a lighting signal value in accordance with a lighting model, and the number of bits therein is reduced to correspond to the number of bits in each data value required by the frame buffer, and the lighting data values are sent as color values to the frame buffer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.