CGAL 3.4：如何从 Finite_edges_iterator 获取结束顶点坐标？
这是一些代码：
struct K : CGAL::Exact_predicates_inexact_constructions_kernel {};
typedef CGAL::Triangulation_vertex_base_2<K> Vb;
typedef CGAL::Constrained_triangulation_face_base_2<K> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb,Fb> TDS;
typedef CGAL::Exact_predicates_tag Itag;
typedef CGAL::Constrained_triangulation_2<K, TDS, Itag> CT;
typedef CT::Point Point;
for (CT::Finite_edges_iterator eit = ct.finite_edges_begin();
eit != ct.finite_edges_end(); ++eit){
// TODO: list vertex co-ordinates here
}
来自 手册:
“边没有显式表示，它们只是通过两个面的邻接关系隐式表示。每条边有两个隐式表示：与索引 i 的顶点相对的面 f 的边，可以表示为以及 f 的邻居(i) 的边。”
这对我来说没问题......但是如何在上面给出的代码中使用 CT::Finite_edges_iterator 获取边缘的末端顶点？
更新： 我设法想出了这个解决方案：
Segment s = ct.segment(eit);
const Point& p1 = s.point(0);
const Point& p2 = s.point(1);
我仍在寻找更好的方法来做到这一点。
Here is some code:
struct K : CGAL::Exact_predicates_inexact_constructions_kernel {};
typedef CGAL::Triangulation_vertex_base_2<K> Vb;
typedef CGAL::Constrained_triangulation_face_base_2<K> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb,Fb> TDS;
typedef CGAL::Exact_predicates_tag Itag;
typedef CGAL::Constrained_triangulation_2<K, TDS, Itag> CT;
typedef CT::Point Point;
for (CT::Finite_edges_iterator eit = ct.finite_edges_begin();
eit != ct.finite_edges_end(); ++eit){
// TODO: list vertex co-ordinates here
}
From the manual:
"The edges are not explicitly represented, they are only implicitly represented through the adjacency relations of two faces. Each edge has two implicit representations: the edge of a face f which is opposed to the vertex indexed i, can be represented as well as an edge of the neighbor(i) of f."
That's fine by me... but how do I get the end vertices of the edge using a CT::Finite_edges_iterator in the code given above?
Update:
I managed to come up with this solution:
Segment s = ct.segment(eit);
const Point& p1 = s.point(0);
const Point& p2 = s.point(1);
I am still looking for a better way to do this.
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我设法想出了这个解决方案：
我仍在寻找更好的方法来做到这一点。
I managed to come up with this solution:
I am still looking for a better way to do this.
我使用类似
Triangulation::Vertex_handle fVertex = eit->first->vertex(Triangulation::ccw(eit->second)); 的
东西Triangulation::Vertex_handle sVertex = eit->first->vertex(Triangulation::cw(eit->second));
I have using something like
Triangulation::Vertex_handle fVertex = eit->first->vertex(Triangulation::ccw(eit->second));
Triangulation::Vertex_handle sVertex = eit->first->vertex(Triangulation::cw(eit->second));
边提供面上顶点的索引。在 CGAL 中，三角剖分的面只有 3 个顶点。边是三元组； （脸，i，j）。您可以 获取第 i 个（0、1 ，或 2) 使用 vertex(i) 方法获取面的顶点。。因此，要获取顶点，请使用：
The edges provide the indices of the vertices on the face. The face of a triangulation has only 3 vertices in CGAL. Edges are a triplet; (face, i, j). You can get the i-th (either 0, 1, or 2) vertex of a face using the vertex(i) method.. So, to get the vertices, use: