Я новичок в CGAL, и когда я использую функцию .locate() для поиска точки в треугольнике, возникают некоторые проблемы. Сначала я строю треугольник с тремя точками (-1,0) (1,0) (0,1), затем я проверяю взаимное расположение некоторых точек с треугольником, точки:
p0(0.8, 0.1) ---- locate in the triangle; p1(0.95, 0) ---- locate on the edge (-1,0) ---- (1,0); p2(0.8, 0.2) ---- locate on the edge (1,0) ---- (0,1); p3(0.6, 0.4) ---- locate on the edge (1,0) ---- (0,1); p4(0.7,0.3) ---- locate on the edge (1,0) ---- (0,1);
Но результаты поиска:
p0 ---- FACE, right! p1 ---- EDGE, right! p2 ---- OUTSIDE_CONVEX_HULL, wrong! p3 ---- EDGE, right! p4 ---- FACE, wrong!
а точки p2, p3, p4 лежат на одном ребре (1,0) ---- (0,1)
В чем причина проблемы?
Код:
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Delaunay_triangulation_2<K> Delaunay_triangulation;
void main()
{
//generate the triangles
std::vector<Point2> pts;
pts.push_back(Point2(1,0));
pts.push_back(Point2(-1,0));
pts.push_back(Point2(0,1));
Delaunay_triangulation dt;
dt.insert(pts.begin(), pts.end());
//locate point in the triangle
Point2 pt0 = Point2(0.8, 0.1);//the point located in the triangle.(on the FACE ?)
Point2 pt1 = Point2(0.95, 0);//the point located on the segment ( (1,0) ---- (-1,0) ) (on the EDGE ?)
Point2 pt2 = Point2(0.8, 0.2);//the point locate on the segment ( (1,0) ---- (0,1) ) (on the EDGE ?)
Point2 pt3 = Point2(0.6, 0.4);//the point locate on the segment ( (1,0) ---- (0,1) ) (on the EDGE ?)
Point2 pt4 = Point2(0.7,0.3);//the point locate on the segment ( (1,0) --- (0,1) ) (on the EDGE ?)
Face_handle fh0, fh1, fh2, fh3, fh4;
Delaunay_triangulation::Locate_type lt0, lt1, lt2, lt3, lt4;
int li;
fh0 = dt.locate(pt0, lt0, li);//for pt0, lt0 is equal to FACE, right!
fh1 = dt.locate(pt1, lt1, li);//for pt1, lt1 is equal to EDGE, right!
fh2 = dt.locate(pt2, lt2, li);//for pt2, lt2 is equal to OUTSIDE_CONVEX_HULL, I think it's wrong!
fh3 = dt.locate(pt3, lt3, li);//for pt3, lt3 is equal to EDGE, right!
fh4 = dt.locate(pt4, lt4, li);//for pt4, lt3 is equal to FACE, I thing it's wrong!
}