A method for deriving a reciprocal value of the homogeneous coordinate w for use in the production of rational cubic functions for the image production on a display and arrangement for carrying out the method

摘要

An adaptive forward differencing apparatus, wherein, when rendering curves, calculated x, y values are increased or decreased in order to create values which correspond to the next pixel of the display CRT, such that curves of substantially one pixel increments are continuously and uniformly generated. The apparatus also provides circuitry for generating coordinates of display elements which approximate an ideal vector and to define curves, vectors or objects within maximum and minimum coordinates of the CRT display. The apparatus also provides efficient circuitry for computing the value of 1/w of the homogenous coordinate w.