THREE-DIMENSIONAL PICTURE FORMING DEVICE

PURPOSE:To erase a hidden surface at high speed by dividing R, G, B and Z buffer memories into an mXn pcs. of memory units, providing an adder-subtractor in the Z buffer memory and a mechanism capable of simultaneously reading and writing a luminance value an depth, in the respective memory units. CONSTITUTION:R, G, B and Z buffer memories 2a-2c and 3 are equipped with the mXn number of the memory units and the respective memory units store the information of picture elements, for which a remainder (i) in case an (x) coordinate of display picture coordinates in each picture is divided by a positive integer number (m) shows the same value as a remainder (j) in case a (y) coordinate is divided by a positive integer number (n) in the coupling (i,j). The respective memory units of the Z buffer memory 3 are equipped with the adder-subtractor for the comparison and cumulation of depth (z) and further, the respective memory units of the R, G, B and Z buffer memories 2a-2c and 3 are equipped with the mechanism to simultaneously read the luminance value and depth and the mechanism to simultaneously write the luminance value and depth under the condition of a compared result for the depth (z). Thus, a processing time needed for picture formation with the erasion of the hidden surface.