Sorting and the hidden-surface problem

Computer animation

“…It is based on some of the latest programming techniques including structured programming* and it solves (actually avoids) the sorting problem as expressed by Ivan Sutherland (13), et al This algorithm functions by efficiently accomplishing the work to be done as opposed to using time consuming strategies to avoid this work, as is the case with previous algorithms. Thus, it represents the first of a new class of algorithms.…”

Design of an algorithm for the display of visible surfaces

“…However, a sufficient number of intensity levels can always be simulated using averaging or pseudorandom coding [10] ; for example, if an intensity of 10.75 were desired, we could output 10 1/4 of the time and 11 grid; then this information is transformed (reduced) 2 so that it fits into K samples. The simplest such transforma-2 tion that is of any use is to effectively divide the (NK) 47 2 grid into K NxN blocks.…”

“…As inFigure 18c, the two cases shown are indistinguishable if the faces arc written out separately, even though the further face in the left case should not be visible at all. Surtherland has proposed a new visible surface algorithm[11] that combines the best features of the Newell and Watkins approaches; in particular, the algorithm can supply an ordered list of 50 segments so that transparency calculations are feasible, and also exactly what segment is visible at each sample point, to avoid the problem ofFigure 18c.…”

The feudal priority algorithm on hidden-surface removal

“…Schumacker [10,11,12,15] observed that within a cluster the face priority is a property of the topology of the cluster and can be calculated independently of the viewpoint if the environment, i.e., objects, can be divided into several adequate clusters. The cluster priority is determined by isolating clusters with separating planes and is dependent on the location of the viewpoint relative to the separating planes.…”