| 摘要 |
A method and apparatus for supporting accumulation buffering in a video graphics system is presented. An accumulation buffer is included in the system, and the accumulation buffer stores an accumulation data set for each pixel of a frame. Preferably, each accumulation data set includes accumulated color data and a counter value. A Z buffer is included in the system, where the Z buffer stores Z data for each pixel of the frame. A drawing buffer stores a color data set for each pixel of the frame, where each color data set includes color data and a valid indication. A mask buffer includes a plurality of pixel block indicators, where each of the plurality of pixel block indicators corresponds to a plurality of pixels of the frame. When a pixel block indicator is set, pixels included in a corresponding plurality of pixels that have set valid indications in the drawing buffer are understood to have valid color data stored in the drawing buffer and valid Z data stored in the Z buffer. A rendering block renders images into the drawing buffer and the Z buffer while utilizing the pixel block indicators from the mask buffer and the valid indications of the drawing buffer. Utilization of the pixel block indicators and valid indications simplifies the rendering process. At the completion of each image rendering, a controller blends color data for those pixels that have valid color data stored in the drawing buffer with the currently accumulated color data for corresponding pixels stored in the accumulation buffer.
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