The Clipper Primitives metric represents the number of primitives that flowed out of the clipper. The metric includes original primitives which passed the trivial clipping test (trivial accept) and new primitives that were created by the clipper as a result of the clipping operation.
- If you render 100 triangles and clipping is enabled and all the triangles are trivially accepted, the Clipper Primitives is 100.
- If you render 100 triangles and clipping is enabled and all the triangles are trivially rejected, the Clipper Primitives is 0.
- If you render 100 triangles and clipping is enabled and one or more triangles are partially located within the viewing frustum, the Clipper Primitives returns a value which could be more or less than 100 depending on the number of triangles that were clipped. If value is significantly higher than 100, it means that many triangles were partially clipped, and the clipper created additional triangles.
In most cases you do not have to care about the clipper performance on Intel® HD Graphics 2000/3000 GPUs because these graphic processors implement an efficient clipping algorithm in silicon.