Clipping of graphics primitives

Techniques for performing clipping of graphics primitives with respect to a clipping boundary are described. The clipping step may be performed separately for each tile of a graphics frame to be rendered, after a primitive list for the tile has been read from a primitive memory. Clipping may be performed only for larger primitives whose size exceeds a given threshold 100. If the primitive size exceeds the threshold a clipping operation is performed, during which new vertex data is generated 106 for the clipped primitive. If the primitive size does not exceed the threshold, the clipping operation is not performed 102. Subsequent processing of the primitives is performed on the outcome of this determination 104,108. Clipping of a primitive to the clipping boundary may be performed inexactly so that only a single clipped primitive is generated which may extend beyond the clipping boundary. A clipped primitive generated by clipping may be used for a depth function calculation of a primitive ...