Clipping device

A clipping device for judging whether vertexes of a primitive expressed by a predetermined coordinate system are inside or outside of a multi-dimensional region of an object to be drawn, a polyhedron being drawn in units of primitives including a plurality of vertexes, comprising:

• a clip code generation circuit for generating clip codes obtained by setting data in accordance with results of comparison of vertex coordinates of said primitive and a judgment refer nce value of said multi-dimensional region and a negative value of the judgment reference value as bit data for the amount of the vertexes of the primitive;
• a current clip register for a shifting the clip codes generated at said clip code generation circuit in accordance with a control signal;
• clip registers of at least a number smaller than the number of the vertexes of said primitive by one cascade connected to an output of said current clip register and able to replace the held data with the clip codes held by the register of a previous stage in accordance with a control signal;
• a control circuit for outputting said control signal to the current clip register when receiving a clip code generation instruction to shift the clip codes generated at said clip code generation circuit and outputting said control signal to a corresponding clip register so as to replace the clip codes between adjacent clip registers including said current clip register when receiving a replacement instruction;
• and
• a logic circuit for performing a logic operation with respect to all bit data set in the clip registers including said current clip register and setting a clip flag indicating whether or not the vertex to be judged is inside or outside the multi-dimensional region of the object to be drawn.