Patent ID: 6232986
Filing Date: 2001-05-15
Classification: G06T

Abstract:
A three-dimensional graphics processing apparatus in which a drawing processing of a polygon is performed through a digital differential analyzer DDA processing, comprising:a parameter computation unit for calculating parameters based on vertex data of the polygon on a screen coordinate system, the vertex data being obtained by a geometrical transformation; anda digital differential analyzer DDA unit for producing pixel data, defining a polygon image on a screen, based on the vertex data and the parameters from the parameter computation unit through the DDA processing, wherein the DDA unit performs the DDA processing, including a left DDA processing a right DDA processing, and a middle DDA processing, in a controlled sequence for each of dots on a scan line, the dots including a right endpoint dot and a left endpoint dot where the scan line intersects a polygon right edge and a polygon left edge, respectively, and the DDA unit outputs the pixel data corresponding to one of the dots to a frame buffer substantially every time said DDA processing for said one of the dots is performed, and wherein the DDA unit includes a DDA operation circuit which performs a selected one of the left DDA processing, the right DDA processing, and the middle DDA processing to produce each of an x-coordinate, a z-value, a color value, and a y-coordinate for said one of the dots based on at least one of the vertex data and the parameters supplied by the parameter computation unit, and outputs the resulting value.