Three dimensional parallel drawing apparatus for synthesizing graphics data with image data using a pixel depth buffer and an image depth register

Abstract

A three-dimensional graphics drawing apparatus having a plurality of frame buffers, a Z buffer and a Z register. The frame buffers are for writing pixel data into an address designated by coordinate values (X, Y) of ZY display coordinates and for storing an image. The Z buffer is for storing a plurality of coordinate values (Z) indicating a depth direction for each pixel data written by the frame buffer. The Z register is an alternative to the Z buffer and is used for writing a single coordinate value (Z) in place of storing the coordinate value Z for every pixel in the Z buffer, when the coordinate value (Z) in the depth direction of the pixel data stored in the frame buffer have the same value for all of the pixel data. A merge unit is provided for selecting visible pixel data from the plurality of pixel data read from the frame buffer on the basis of the coordinate value (Z) in the Z buffer and the Z register. The merge unit subsequently writes the selected pixel data into a frame buffer for synthesis.

Dependencies are inferred from the claim text.