| 摘要 |
PURPOSE:To obtain a hidden-surface removed graphic at a high speed by storing types, positions, and inclinations of primitives corresponding to a display body, and judging whether a point on a test line extending from an optional visual point is within the primitives or not. CONSTITUTION:When bodies A and B are present in front-rear relation, plural test lines 5 extending from the visual point O are considered and logic ''1'' or ''0'' is set according to whether respective points on the test lines are inside or outside the bodies A and B. Logic ''1'' is obtained for the body A and logic ''0'' is obtained for the body B at a point a' on a test line 5-2; and logic ''1'' is obtained by arithmetic defined by A(-)B. Then, the point a' where the result changes into logic 1 is registered as ''point on front surface'' on the test line 5-2. Then, 0-1=0 at a point (a), 1-1=0 at a point (b), and 1-0=1 at a point (c) as to a test line 5-5, so that the point (c) is registered as ''point on front surface''. |
