| 摘要 |
PURPOSE:To make judgement of crossing accurate by judging existence of intersection of a rectangular plane and a line segment forming the locus of a discharged shell, etc., at a shooting game in three dimensional coordinates by indicating with a rectangular plane and three dimensional coordinates. CONSTITUTION:When the crossing of an rectangular plane P and a line segment forming a locus S of a discharged shell, etc., indicated by three dimensional coordinates is to be judged, parallel relation between the rectangular plane P and the locus S is judged at first. When the relation is judged not parallel, it is judged that whether or not the intersection Sc is on the line segment indicated with coordinates data, (X, Y, Z) and (X0, Y0, Z0) between two points on the locus S, and when it is, the coordinates of the intersection om the line segment are calcurated. Then the rectangular plane P is projected on a secondary plane having the smallest angle from the rectangular plane P, for example, secondary plane XZ, and the two dimensional coordinates Axz-Dxz in the rectangular plane area are calculated. Then the intersection Sc is projected on the two dimensional surface XZ, the outer product of vectos toward the intersection Scxz of the line segment and the dimensional plane XZ, and the apexes A-D. When all the outer products are positive, it is determined crossing. |
