Rational Z-buffer for decreasing a likelihood of Z-buffer collisions
US8154546B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 2008 |
| Grant date | Apr 10, 2012 |
| Priority date | — |
| Expiry date | Feb 7, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/405
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A “Rational Z-Buffer” provides various techniques for reducing artifacts when rendering graphics using z-buffers. In particular, the Rational Z-Buffer reduces the likelihood of z-buffer collisions when using hardware or software z-buffer algorithms to render graphics by delaying homogenous division of pixels until after occlusion testing. Further, occlusion testing between any two pixels, p0 and p1, is accomplished by comparing rational depth values, r0={z0, w0} and r1={z1, w1}, for pixel p0 and p1 to determine which pixels are visible. Depth values are compared by determining whether the expression z0w1<z1w0 is true. If true, then pixel p0 occludes pixel p1 in clipping cube space relative to an image-plane defined by a particular viewpoint and the field of view. Further, since homogeneous division by w is not performed prior to occlusion testing, rational depth values are uniformly distributed clipping-cube space, thereby significantly reducing potential z collisions relative to conventional z-buffer testing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.