OPERATION METHOD OF PIXEL CACHE STRUCTURE IN THREE-DIMENSIONAL GRAPHIC ACCELERATOR

摘要

PURPOSE: An operation method of a pixel cache structure in a three-dimensional graphic accelerator is provided to reduce cache pollution by loading only data with the high probability of being reused, thereby increasing a cache success rate. CONSTITUTION: Information of the existing fragment having the same texture coordinates as a newly inputted segment are detected from a pixel cache(421) and an NT(Non-Temporal) buffer(422). A depth value of the newly inputted fragment is compared with a depth value of the existing fragment. If the depth value of the newly inputted fragment is larger than the depth value of the existing fragment, information of the newly inputted fragment is stored in the NT buffer. If the depth value of the newly inputted fragment is smaller than the depth value of the existing fragment, the information of the newly inputted fragment is stored in the pixel cache. A color reading unit(413) executes a read operation of a color value of the newly inputted fragment. An alpha mixing unit(415) executes alpha mixing to the read color value and a color value mixed in a texture mixing unit(403). A color write unit(417) stores the alpha-mixed color value in the pixel cache.