Picking function for a pipeline graphics system using hierarchical graphics structures
US5255359A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1989 |
| Grant date | Oct 19, 1993 |
| Priority date | — |
| Expiry date | Oct 23, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/04842
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A graphics display system picking function tracks machine states of pickable primitive operators through the use of a pick stack and machine state memory. The pick stack operates as a stack when accessed by pipeline processors. Pipeline processors can add an element to the stack or remove elements from the stack as structures are processed. Selection or picking of an object causes a graphics control processor to randomly access the pick stack to determine the attributes of a picked primitive. The machine state memory is implemented as a video RAM allowing rapid copying of rows containing machine states for various structure levels in the hierarchy. A first area of the machine state memory stores the states relating to the structures in the hierarchy as they are executed. A second area retains an abbreviated state description for each pickable primitive while a final area contains abbreviated machine state information for picked objects to be echoed by the system. The pick stack and machine state memories operate together to provide rapid pick identification, picked primitive machine state identification, and picked primitive echoing. The use of separate picked primitive echo machin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.