Method and system for efficient antialiased rendering

Abstract

A method and system are disclosed for antialiased rendering a plurality of pixels in a computer system. The method and system comprise providing a fixed storage area and providing a plurality of sequential format levels for the plurality of pixels within the fixed storage area. The plurality of format levels represent pixels with varying degrees of complexity in subpixel geometry visible within the pixel. A system and method in accordance with the present invention provides at least the following format levels: one-fragment format, used when one surface fully covers a pixel; two-fragment format, used when two surfaces together cover a pixel; and multisample format, used when three or more surfaces cover a pixel. The method and system further comprise storing the plurality of pixels at a lowest appropriate format level within the fixed storage area, so that a minimum amount of data is transferred to and from the fixed storage area. The method and system further comprise procedures for converting pixels from one format level to take into account newly rendered pixel fragments. All formats represent depth values in a consistent manner so that fragments rendered during later rendering passes match depth values resulting from rendering the same primitive in earlier passes. Thus, the invention enables high-quality antialiasing with minimal data transferred to and from the fixed storage area, while supporting multi-pass rendering.