Ray tracing through an ordered array

Abstract

A system for displaying sets of surface cubes with gradient vertex vectors first employs a pointer table constructed to order the surface cubes so as to generally cause a row by row and layer by layer ordering during model creation. During display, a viewpoint is selected and a scan controller causes cubes to be displayed according to this order of the pointer table. A test backprojection of cubes to image plane is performed to determine which pixels will be impinged by the cubes. For pixels which have not been updated, or pixels which have been updated by a less superficial cube than the current cube, projection rays are created through the center of impinged pixels in a direction opposite that of the backprojection. An intersection point of the ray with a surface within a current cube is determined. The data value and gradient vectors for the current cube are interpolated at this intersection point. These interpolated vector and value are then rendered to produce and image with less distortion and with less processing complexity.