| 摘要 |
PURPOSE:To reduce the storage capacity or a data storage area where graphic data is stored. CONSTITUTION:Graphics in a graphic list stored in a main memory 30 are transposed in the ascending order of Z values so that they can be plotted in order from the foremost graphics, and a one-bit flag indicating whether a picture element is already plotted or not is set to each picture element of a frame buffer 60. When graphics in the graphic list are plotted in the sort order, picture elements whose Z bits are '1' are recognized as already plotted, and original graphic data is used as graphic data corresponding to these picture elements. Picture elements whose Z bits are '0' are regarded as not plotted, and graphic data according with picture information in the graphic list is generated and is plotted in the frame buffer 60, and Z bits of these picture elements are set to '1'. Consequently, the information on Z comparison requires on bit per picture element to reduce the memory capacity. |
