Patent ID: 6940520

Claim:
An anisotropic texture filtering method for three-dimensional processing, by a computer, of an image to be displayed on a computer graphics display, the method using area coverage weight of sub-texel precision, comprising the steps of: mapping a footprint of a pixel of the image onto a texture area; executing filtering of the image by applying weights to texels enclosed in a rectangular region enclosing the footprint that is mapped from the pixel onto the texture area; using a multiplication of the footprint area coverage weights of sub-texel precision and the Gaussian filter value as said weight for the relevant texel; representing four sides of the footprint by four linear equations surrounding the footprint in clockwise sequence for computing said area coverage weight of sub-texel precision; obtaining sub-texel masks from table by addresses given by values of line equations on substituting slope of the lines and coordinates of the texels; and calculating the final area coverage weight by logically bit-by-bit multiplying four sub-texel masks obtained in the previous step.