Patent attributes
The VPC unit and setup unit of a graphics processing subsystem perform culling operations. The VPC unit performs culling operations on geometric primitives falling within a specific criteria, such as having a property within a numerical range limit of the VPC unit. This limitation reduces the complexity of the VPC unit. As increasing rendering complexity typically produces a large number of small primitives, the VPC unit can cull many primitives despite its culling limitations. The VPC unit also includes a cache for storing previously processed vertices in their transformed form, along with culling information previously computed for the vertices. To minimize memory bandwidth, the VPC unit retrieves vertex data used for culling operations first. After completing the culling operations, the VPC unit retrieves the attributes of a vertex only if the primitive has not been culled. The VPC unit applies a perspective correction factor to the vertex attributes.
