| 摘要 |
PURPOSE:To shorten the write time of coordinate data by directly writing the coordinate data to a memory storage position when it is decided that the data are not written before the memory storage position. CONSTITUTION:Coordinate data Xc and Yc are respectively added as the address of a depth buffer memory 8 and the address of a flag memory 13, and coordinate data Zc are set as the data input of a comparator 36 and a memory 8. As soon as information is read from the memory 13, whether or not the writing is executed before is determined, and data Z are sent from the memory 8 to the comparator 36. When the data are not written before, the data Zc are unconditionally written to the memory 8, and the processing is advanced in response to the next coordinate output from a straight line generator 7. When the data Z are written to the memory 8 before, based on the comparison result between the data Z and Zc (Zc < Z), the write processing of the data Zc to the memory 8 are executed. |
