Patent ID: 7292239

Claim:
A graphics processing subsystem configured to render a stream of primitives, the graphics processing subsystem comprising: a first cache memory configured to store a set of vertices associated with at least a portion of a first stream of primitives, each vertex including a position and a set of at least one attribute; a viewport and culling unit configured to receive the first stream of primitives, wherein each primitive includes a set of references to a subset of the set of vertices of the first cache memory, and including a culling unit and an attribute unit, and wherein the viewport and culling unit includes a second cache memory; and wherein for each one of the first stream of primitives, the culling unit is configured to determine if a copy of at least a portion of the subset of the set of vertices has been previously stored in the second cache memory, to retrieve the positions of each of the portion of subset of the set of vertices from the second cache memory in response to a determination that the second cache memory is storing a copy of the portion of the subset of the set of vertices, and to retrieve the position of each of the portion subset of the set of vertices from the first cache memory in response to a determination that the second cache memory is not storing a copy of the portion of the subset of the set of vertices and to determine the potential visibility of the primitive associated with the subset, and wherein in response to a determination that the primitive is potentially visible, the attribute unit is configured to retrieve each of the sets of attributes of the subset of the set of vertices associated with the primitive from the first cache memory using the set of references.