Patent ID: 7714877

Claim:
A graphics processing apparatus, comprising: an instruction memory including a single clipping distance instruction to determine a clipping distance with respect to any of multiple clipping planes, wherein the single clipping distance instruction is implemented in software and docs not account for different ones of the clipping planes; a clipping plane register including a clipping plane identifier that specifies a particular one of the clipping planes with respect to which the clipping distance is to be determined; and a clipping unit connected to the instruction memory and the clipping plane register, wherein the clipping unit is implemented in hardware and is responsive to the single clipping distance instruction to perform clipping plane-specific operations for different ones of the clipping planes, wherein the clipping unit is configured to: (i) access the clipping plane register to identify the particular one of the clipping planes with respect to which the clipping distance is to be determined; (ii) perform a first set of clipping plane-specific operations implemented in hardware to determine the clipping distance, if the particular one of the clipping planes corresponds to a first clipping plane; and (iii) else if the particular one of the clipping planes corresponds to a second clipping plane, perform a second set of clipping plane-specific operations implemented in hardware to determine the clipping distance, wherein the first set of clipping plane-specific operations and the second set of clipping plane-specific operations are different.