Patent ID: 6445392
Filing Date: 2002-09-03
Classification: G06T

Abstract:
A method for determining Z values for a fragment in an anti-aliasing video graphics system, comprising:sampling the fragment to produce a mask including a plurality of samples, wherein a valid sample indicates coverage of a pixel by the fragment at a portion of the pixel corresponding to the valid sample, wherein the fragment sampling includes: determining a Z value at a reference of the pixel, determining slopes of the Z value in two directions with respect to the reference point; determining a Z value of a front most valid sample of the plurality of samples by: identifying which of the pixels is the front most valid sample based on the slopes, position of each of the plurality of samples with respect to the reference point and the mask, and calculating the Z value of the front most valid pixel based on position of the front most valid pixel in relation to the reference point, the slopes and the Z value at the reference point, wherein the Z value of the front most valid sample represents spatial depth of the fragment at the point within the fragment corresponding to the front most sample; and utilizing the Z value of the front most valid sample as the Z value for all samples in the plurality of samples.