Techniques for performing clipping of graphics primitives 60 with respect to a clipping boundary 65 are described. The clipping step 10 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 38. Clipping may be performed only for larger primitives whose size exceeds a given threshold. Clipping of a primitive 60 to the clipping boundary 65 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 setup operation and not for an edge determination.