Abstract: A clip-cull-viewport (CCV) unit manages information associated with vertices of a primitive as the primitive passes through the CCV unit. The CCV unit includes an index cache and a cache-status table. Vertices of a received primitive are stored in locations within the index cache based on attribute and index fields of the primitive. If a vertex is a reused vertex of another primitive that matches a valid entry in the cache-status table and if the primitive survives being culled, the valid entry in the cache-status table is preserved, the attribute field of the primitive is set to indicate that the vertex is a reused vertex, and the primitive is sent to an output interface for a downstream unit. Otherwise, the attribute field is set to indicate that the vertex is not reused, and the primitive is sent to the output interface for the downstream unit.

Abstract: A clip-cull-viewport (CCV) unit manages information associated with vertices of a primitive as the primitive passes through the CCV unit. The CCV unit includes an index cache and a cache-status table. Vertices of a received primitive are stored in locations within the index cache based on attribute and index fields of the primitive. If a vertex is a reused vertex of another primitive that matches a valid entry in the cache-status table and if the primitive survives being culled, the valid entry in the cache-status table is preserved, the attribute field of the primitive is set to indicate that the vertex is a reused vertex, and the primitive is sent to an output interface for a downstream unit. Otherwise, the attribute field is set to indicate that the vertex is not reused, and the primitive is sent to the output interface for the downstream unit.

Abstract: A method for rendering polygons in a computer graphics system in which the computer display is divided into a plurality of subregions, and the rasterization process is performed in a micro framebuffer for each subregion, rather than sending raster data for each triangle into the frame buffer. Each polygon undergoes a first stage bounding box intersection test to identify the subregions which are likely to intersect with the polygon. If the number or configuration of intersected subregions exceeds a predetermined threshold requirement, then the polygon undergoes a more precise second stage intersection test to identify which subregions are actually intersected by the polygon. If the number or configuration of intersected subregions is below the threshold requirement, then the control data for the polygon is passed on to each of the identified subregions.