| 摘要 |
PURPOSE:To attain a high-speed action by processing the display of a three-dimensional graphic together with the raster scan in displaying only by giving a data of straight line elements to either a straight line group constituting the plane of a graphic and the three orthogonally crossing axes. CONSTITUTION:Surface display circuits 10-1-10-3 stores shapes on the three planes orthogonally crossing with the three-dimensional orthogonally crossing coordinate axes. Assuming that the raster scan is achieved from the left top of a display screen to its right bottom, an azimuth detection part 12 outputs the azimuth of a raster position in accordance with the raster position in a raster display cycle and the positions of the three axes shown by axis registers 11-1-11-3. The raster position is judged as to whether or not it is within an area on a plane stored in the respective surface display circuits 10-1-10-3. A priority decision circuit 15, when the surfaces are overlapped at a certain raster position, selects a surface in accordance with the azimuth of the raster position. When the azimuth is zero, a surface (b) is selected with priority, but if the surface (b) does not exist, a surface (a) is selected, but if both surfaces (a) and (b) do not exist, a surface (c) is selected. For the surface outputted through the circuit 15, a display element selection circuit 16 selects a display element corresponding to each of the surfaces, and the element is displayed in a display device 17. |
