We present a simple method for eliminating most pixelpositioning errors when rendering lines and polygons with Bresenham’s algorithm. Our method affects only the calculation of the initial values for Bresenham’s vectorgenerating algorithm. It doesn’t alter the actual vectorgenerating algorithm, requiring only integer arithmetic to find the next pixel in a vector. Our method eliminates all dropouts and virtually all overlaps between adjacent polygons whose edges lie on the same line. This eliminates the need to “grow” polygons to avoid dropouts and opens the possibility of drawing surfaces composed of adjacent polygons with read/modify/write pixel operations, such as Add or alpha buffering. We also show that most rendering artifacts of today’s display controllers ultimately result from pixelpositioning errors, not insufficient z-buffer resolution. © 1990 IEEE
