| 摘要 |
PURPOSE:To perform a quick processing for a hidden line, by discriminating in-sight/out-of-signt of a pattern element from visual point by a flag. CONSTITUTION:Contents of a visual point direction register 11 indicating the direction of a visual point are sent to a determing equipment 12 for the discrimination object visual point to determine a point out of a finite number of points which is used to discriminate in-sight/out-of-sight, and this point is stored in a visual point number register 13. In respect to segments to be displayed, segment data 15 and flags 16 are read out together from a segment data memory 14 and are sent to an in-sight/out-of-sight discriminator 17. The discriminator 17 discriminates in-sight/out-of-sight of segments on a basis of flags of segments and contents of the register 11, and segment data of seen segments and indistinct segments are stored in a segment memory 18. In this case, in-sight/out-of-sight is discriminated with values indicating state of flag for the visual point position indicated by the register 13. |
