METHOD AND APPARATUS FOR GENERATING SUB PIXEL MASKS IN A THREE DIMENSIONAL GRAPHIC PROCESSING SYSTEM

A method and apparatus for providing video graphics processing that includes anti-aliasing begins when a video graphics processor receives vertex parameters of an object-element and walks a first edge of the object element and a second edge of the object element. The video graphics processor walks the first and second edges based on calculations involving a decision corner and an error turn. The calculations indicate which direction to walk on a pixel by pixel basis, i.e., whether the walking should be in the major direction or the minor direction. The calculations also identify pixels that contain fragment pixel information, i.e., the pixels along the edges of the object element. For each fragment pixel, subpixel masks are created for each object element that is present in the fragmented pixel. From the subpixel masks, subpixel sequences are determined, which are used to produce pixel information of the fragment pixel.