CLAMPING OF z VALUE IN NEAR RANGE OF z FOR MAXIMIZING ACCURACY OF VISUALLY IMPORTANT z COMPONENT AND EVADING CLIPPING NEAR z IN GRAPHICS RENDERING SYSTEM

摘要

PROBLEM TO BE SOLVED: To secure accuracy of depth of a z value when depth data of the z value should be compressed in a 3D (three-dimensional) graphics rendering system. ;SOLUTION: A graphics pipe line performs z buffering and when an anti- aliasing rendering mode is selected, z value bit compression is performed to more efficiently use usable z buffer memory. The accuracy of visually important z components is improved by using z clamping structure by clamping the z value of a pixel within a prescribed z axis range in the vicinity of a z=0 view/ camera (view port) plane. This fact enables use of a z clipping surface of excessively in the vicinity of the viewpoint/camera plane and the accuracy of the z value to the remaining depth of a scene is secured as evading undesirable visual artifact which is generated when the object rendered in the vicinity of the viewpoint/camera plane is clipped.;COPYRIGHT: (C)2003,JPO