| 主权项 |
1. A method of assigning primitives to tiles in a graphics processing system which has a rendering space subdivided into a plurality of tiles, wherein each tile comprises one or more polygonal regions for which depth comparisons are to be performed, the method comprising:
in said graphics processing system:
receiving a plurality of primitives forming a mesh,identifying external edges of the mesh,identifying intersection points where the identified external edges of the mesh intersect with lines aligned with the edges of a polygonal region of a tile, and using the identified intersection points to determine whether the mesh entirely covers the polygonal region of the tile,for each of a plurality of the received primitives which are present within the polygonal region of the tile:
(i) comparing a first depth value for the primitive with a depth threshold for the region, and(ii) in dependence on the result of the comparison, selectively including an indication of the primitive in a display list for the tile to thereby assign the primitive to the tile; andif it is determined that the mesh entirely covers the polygonal region of the tile, updating the depth threshold for the polygonal region in dependence on a comparison of the depth threshold for the polygonal region with a second depth value for at least one of said plurality of the received primitives of the mesh which is present within the polygonal region of the tile. |
