Clustered Backface CUlling

A backface culling technique for clusters of polygons, as well as a method for generating efficient clusters from a set of triangle strips. The cluster backface test is directly derived from the traditional single-polygon test, and has about the same complexity. Memory requirements are 40 bytes per test. The cluster backface tests may be arranged hierarchically, with frontface tests added for symmetry. Experiments show graphics performance improvements of up to 50% in terms of number of effective polygons rendered per second.