The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 02, 1998
Filed:
Jan. 31, 1996
Ronald D Larson, Fort Collins, CO (US);
Charles R Dowdell, Nashua, NH (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A computer graphics system utilizes caching of pixel Z values to improve rendering performance. Apparatus for updating the Z values corresponding to pixels of a computer graphics display includes a memory for storing current Z values representing depths at corresponding pixel locations, a Z cache for storing a subset of the current Z values which are stored in the memory, and a comparator for comparing a new Z value with a corresponding current Z value and indicating a pass when the new Z value satisfies a predetermined criteria. The current Z value is read from the Z cache when the current Z value is stored in the Z cache and is read from the memory when the current Z value is not stored in the Z cache. The new Z value is written into the Z cache when the comparator indicates a pass. Each cache entry preferably includes a tile of current Z values corresponding to pixels having a predefined relationship. Different tile configurations may be selected for optimum rendering performance.