a geometry translation processor used when drawing a polygon on a display translates coordinates and efficiently carries out a clipping test to determine whether or not the polygon must be clipped on the display . the processor has operation units , clipping comparators provided for the operation units , respectively , and a clipping register . the clipping comparators compare the elements of a translated coordinate vector with the remaining element of the same vector . the clipping register is used to store the outputs of the clipping comparators and speedily carry out the clipping test .