| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of an error in advance by equalizing the number of projecting polygons with the number of triangles obtained by a triangle dividing method at the worst and to mostly make it less than the number of the triangles. SOLUTION: Whether each vertex of a recessed polygon is recessed or projected is judged, all the recessed vertexes are stored (SP 1) in a recessed vertex list and whether a recessed vertex exists in the recessed vertex list is judged (SP 2). When the recessed vertex exists, the recessed vertex is fetched (SP 3) from the head of the recessed vertex list, three vertexes consecutive in a prescribed direction including the fetched recessed vertex are noticed (SP 4) and whether a triangle formed by these three vertexes can be cut off or not is judged (SP 5). Then when it is judged that the triangle can be cut off, whether an N-polygon can be cut off not is judged. (SP 6). When it is possible, the N-polygon is cut off (SP 7) but when it is impossible on the contrary, the triangle is cut off (SP 8). |
