Browse Prior Art Database

Fast Z-Buffer Memory for Computer-Graphics Applications

IP.com Disclosure Number: IPCOM000116880D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Knittel, G: AUTHOR [+3]

Abstract

Disclosed is a structure and method of operation for a fast z-buffer memory device for graphical applications on computer systems. More specifically, disclosed is the advantageous modification of a Dynamic Random Access Memory (DRAM) for the use in a computer-graphics system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 68% of the total text.

Fast Z-Buffer Memory for Computer-Graphics Applications

      Disclosed is a structure and method of operation for a fast
z-buffer memory device for graphical applications on computer
systems.  More specifically, disclosed is the advantageous
modification of a Dynamic Random Access Memory (DRAM) for the use in
a computer-graphics system.

      For the presentation of three-dimensional objects on
two-dimensional displays, e.g., on two-dimensional computer displays,
hidden parts of the three-dimensional objects have to be eliminated
from the display.  For this purpose z-buffer algorithms (1) have
been used, calculating and comparing virtual z-values, but bearing an
inherent memory bandwidth problem.

      This bandwidth problem can be solved by integrating the compare
logic of the z-buffer into the z-buffer algorithm DRAM device (2), in
particular by integrating the z-value compare-function in the
existing registers of the RAM/DRAM storing the z-values.

      In an advantageous embodiment a further arithmetic unit can be
added-to or even integrated-in the z-buffer memory in order to modify
the z-value data provided from external to be checked against the
respective z-value data of the z-buffer DRAM.  This modification is,
e.g., the addition of a constant value which can be stored within the
z-buffer DRAM and which can be calculated as the total differential
of a linear function of two variables.  The purpose of this
arithmetic unit is to shift the sampl...