假设我有一个非简单的多边形， CGAL如何帮助我将其划分为一组简单的多边形？
例如，给出由一系列2D点表示的多边形：
代码语言：javascript复制(1, 1) (1, -1) (-1, 1) (-1, -1) 我希望获得两个多边形;
代码语言：javascript复制(1, 1) (1, -1) (0, 0)和
代码语言：javascript复制(0, 0) (-1, 1) (-1, -1) CGAL是否可行？
1 个答案: 答案 0 :(得分：0)
您需要的两个多边形不构成原始船体。如果您只想使用（0,0）作为顶点之一将原始集合分成三角形，则可以执行此操作：
代码语言：javascript复制#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Constrained_Delaunay_triangulation_2.h>
#include <CGAL/Delaunay_mesh_vertex_base_2.h>
#include <CGAL/Delaunay_mesh_face_base_2.h>
#include <vector>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point_2;
typedef CGAL::Delaunay_mesh_vertex_base_2<K> Vb;
typedef CGAL::Delaunay_mesh_face_base_2<K> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb, Fb> Tds;
typedef CGAL::Constrained_Delaunay_triangulation_2<K, Tds> CDT;
typedef CDT::Vertex_handle Vertex_handle;
typedef CDT::Face_iterator Face_iterator;
int main(int argc, char* argv[])
{
// Create a vector of the points
//
std::vector<Point_2> points2D ;
points2D.push_back(Point_2( 1, 1));
points2D.push_back(Point_2( 1, -1));
points2D.push_back(Point_2( -1, 1));
points2D.push_back(Point_2( -1, -1));
points2D.push_back(Point_2( 0, 0));
size_t numTestPoints = points2D.size();
// Create a constrained delaunay triangulation and add the points
//
CDT cdt;
std::vector<Vertex_handle> vhs;
for (unsigned int i=0; i<numTestPoints; i){
vhs.push_back(cdt.insert(points2D[i]));
}
int i=0;
for (Face_iterator fit = cdt.faces_begin() ; fit != cdt.faces_end(); fit) {
printf("Face %d is (%f,%f) -- (%f,%f) -- (%f,%f) n",i ,
fit->vertex(0)->point().x(),fit->vertex(0)->point().y(),
fit->vertex(1)->point().x(),fit->vertex(1)->point().y(),
fit->vertex(2)->point().x(),fit->vertex(2)->point().y() );
}
return 0 ;
}哪个应该给你这样的输出：
代码语言：javascript复制Face 0 is (0.000000,0.000000) -- (1.000000,-1.000000) -- (1.000000,1.000000)
Face 1 is (0.000000,0.000000) -- (1.000000,1.000000) -- (-1.000000,1.000000)
Face 2 is (-1.000000,-1.000000) -- (0.000000,0.000000) -- (-1.000000,1.000000)
Face 3 is (-1.000000,-1.000000) -- (1.000000,-1.000000) -- (0.000000,0.000000) 
