Patent ID: 8456468

Claim:
A method for rendering a three dimensional scene on a displaying screen divided into tiles, the method comprising: processing primitive data representing submitted primitives of the scene according to a sort-middle technique, the processing including: providing, for a tile of a current scene, a hierarchical z-buffer which comprises a plurality of levels organized according to depth values of the tile; for each of the submitted primitives: calculating a minimum depth value of the submitted primitive; calculating an intersection area associated with said submitted primitive with respect to said tile; providing a plurality of aligned regions each associated with one of the levels of the hierarchical z-buffer so that the intersection area calculated is suitable to be entirely covered by a union of such aligned regions; comparing the minimum depth value of the submitted primitive with corresponding maximum depth values of the aligned region, each maximum depth value being read from the levels of the hierarchical z-buffer; and discarding said submitted primitive if the minimum depth value is bigger than all of the maximum depth values.