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:
May. 08, 1990
Filed:
Jul. 28, 1988
Paul A Winser, Redhill, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
Input data defines the address (X,Y), and an input color (RGB) and depth (Z) for a picture element (pixel) within a stored image. In order to perform hidden-surface removal (HSR), current depth values are stored for each pixel and compared with the input depth value to determine whether or not input data should be written to define a new color and depth for the pixel at (X,Y). The color and depth values are stored in a color RAM (9) and z-RAM (64). To obtain a speed advantage when modifying a series of consecutive pixels and one row of the RAMs, the current depth values are read and compared in advance for each pixel, during the writing period of one or more preceding pixels. The apparatus comprises a control and arithmetic unit (42), and a HSR control circuit (60) in addition to the color RAM (9) and z-RAM (64). The apparatus uses readily available video DRAM chips to provide a z-RAM with two data ports (62,66). The apparatus may form part of an electronic graphics system.