Abstract: A dither unit preferably comprises an offset generator, an adjusted coordinate generator and a dither matrix. The offset generator is coupled to receive information about the relative position of the sub-sample being dithered, and in response generates offset values. The output of the offset generator along with the pixel coordinates are provided to the adjusted coordinate generator which generates adjusted coordinate values used by the dither matrix. The adjusted coordinate values along with a color value are received by the dither matrix, which in response, generates a dithered value for the sub-sample that can be stored back in the over sampling buffer for additional computation.

Abstract: The present invention provides an alpha blending unit that is able to perform alpha blending on sub-samples of a pixel in an efficient manner. The alpha blending unit preferably comprises a plurality of registers for storing a source color, a blending value, and a plurality of destination sub-sample values, multipliers, adders, an accumulator and a divider. The alpha blending unit advantageously sums the destination sub-sample values and then divides them by the number of sub-samples to generate a combined destination color value. This combined destination color value along with the source color and a blending value are then provided to the multipliers, and adders to generate a new destination color value for the pixel.