Patent ID: 6891548

Claim:
In a computer graphics system, a method for calculating a texture-mapping gradient comprising: using a rasterizer to calculate constant values for use in a gradient-calculating equation; passing the constant values to a rational linear interpolator that is configured to calculate the gradient; and computing the gradient using barycentric cordinates and the calculate constant values according to the following equation: G px ={C px −C qx (P n /q n )}/{q n +C qx }, wherein C px =(da/dx)dp 1 +(db/dx)dp 2 , wherein C qx =(da/dx)dq 1 +(db/dx)dq 2 , and wherein da/dx and db/dx are constant values for an entire primitive, for non-zero values of Gpx, as defined by Equation 19 of the specification.