| 摘要 |
PURPOSE:To realize a high-speed and smooth graphic processing by providing a Z buffer storing information indicating the depth of each graphic element. CONSTITUTION:Indication information of a 3-D graphic is stored in a pushup memory, and the information indicating the depth of each graphic element is stored in the Z buffer. A first graphic is plotted while performing a hidden- line and hidden-surface processing, a pick-up mode is activated and a pick-up frame 3 is determined. In the plotting device, the graphic elements are taken out one by one, determination is made whether or not a graphic 2 is within the pick-up frame 3 and in the case of within the pick-up frame 3, comparison with a (z) buffer value is performed. This (z) buffer value indicates a luminance value for a visible surface to be displayed on a screen as a result of the hidden- line and hidden-surface processing, and when the graphic element data are equal to the (z) buffer value, the picked information is written in a memory. When there are plural graphics subjected to pick-up, the one picked up last from among the picked information is adopted. |
