A real-time three-dimensional graphics display

Abstract

The visible surface problem for three dimensional objects is examined from a global point of view in which planar surfaces derived from convex three-dimensional objects are regarded as the natural display elements. By retaining global information on surface and object relationships it is possible to considerably simplify the resolution of visible surfaces for a large class of realistic objects. Implementation of this approach suggests a display in which surfaces written to the display device can overlay and obscure previous picture information in the manner of an oil painting. A display system is proposed in which this is implemented by a large buffer memory which holds a complete point-by-point description of the picture in low-cost MOS shift-registers. By combining new data to be entered in the memory in a variety of ways with the data already present, it is possible to considerably enhance the display’s capabilities. The buffer memory also allows an easy match of the display system to conventional (TV) video equipment.