US 3,944,997 A · Image generator for a multiterminal graphic display system

Abstract

An image generator including a visible edge encoder which receives information defining the visible surfaces of a two-dimensional projection of a three-dimensional world and provides encoded two-dimensional visible edges which are x-ordered and are ready for transmission to a plurality of display terminals. The information received by the visible edge encoder defines the x and y intercepts, in successive planes which include the observer's eye and successive scanlines, of all three-dimensional edges which would be visible to the observer. The information provided by the visible edge encoder is edges which represent a two-dimensional projection of three-dimensional objects, each edge defined by its intended position on a two-dimensional screen and by attributes for a portion of the screen adjacent the edge, such as color, brightness, shading and the like. The edges which are provided by the visible edge encoder and are transmitted to the display terminals, where they are decoded into video raster points, are a highly compressed representation of a video raster; hence, the communication link between the image generator and the terminals can have a relatively low capacity, and the same image generator can service a substantial number of display terminals.

Claims8

Dependent claims

A graphics display system for a display terminal having a display screen for visibly displaying selected points of a raster of display points arranged along regular scanlines, said system including a visible edge encoder comprising:

means for storing a set of edge intercept signals, each edge intercept signal comprising signals positioning a visible intercept point at a selected position along a selected scanline of the display screen and signals defining a plurality of selected visible characteristics of a portion of the same scanline which is adjacent the intercept point;
means responsive to said edge intercept signals in the storing means for generating a plurality of corresponding subsequent signals defining a block of visible edge signals, each visible edge signal comprising signals defining the position of a continuous visible edge along a line on the display screen which need not coincide with a scanline and signals defining selected visible characteristics of a selected two-dimensional portion of the display screen which is adjacent the continuous visible edge;
and
means for transmitting said block of generated visible edge signals to the display terminal, said terminal including means responsive to said generated visible edge signals for displaying the corresponding continuous visible edges and characteristics of the adjacent two-dimensional screen portions by a raster of visible display points along the scanlines of the display screen.

1 more element

A method of operating a graphics display system for a display terminal having a display screen for visibly displaying selected points of a raster of display points arranged along regular scanlines comprising the steps of:

storing a set of edge intercept signals in a first storing means, each edge intercept signal comprising signals positioning a visible intercept point at a selected position along a selected scanline of the display screen and signals defining a plurality of selected visible characteristics of a portion of the same scanline which is adjacent the visible intercept point;
generating from said edge intercept signals in the storing means a block of visible edge signals, each visible edge signal comprising signals defining the position of corresponding subsequent signals defining a continuous visible edge along a line on the display screen which need not coincide with a scanline and signals defining a plurality of selected visible characteristics of a selected two-dimensional portion of the display screen which is adjacent the continuous visible edge;
and
transmitting said block of generated visible edge signals to the display terminal, said terminal responding to said generated visible edge signals to display the corresponding visible edges and characteristics of the adjacent two-dimensional screen portions by a raster of visible display points along the scanlines of the display screen.

1 more element

Dependencies are inferred from the claim text.

Image generator for a multiterminal graphic display system

Life of this patent

Image generator for a multiterminal graphic display system

Life of this patent

Abstract

Claims8