CGAL庫——學習一

PengPengBlog發表於2017-03-31
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Triangulation_3.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <list>
#include <vector>

using namespace std;
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Triangulation_3<K>      Triangulation;
typedef Triangulation::Cell_handle    Cell_handle;
typedef Triangulation::Vertex_handle  Vertex_handle;
typedef Triangulation::Locate_type    Locate_type;
typedef Triangulation::Point          Point;
int main()
{
  // construction from a list of points :
  std::list<Point> L; //
  L.push_front(Point(0,0,0)); //增加一point到連結串列頭。
  //這個時候list L 應該是      (0,1,0) (1,0,0) (0,0,0)
  L.push_front(Point(1,0,0));
  L.push_front(Point(0,1,0));
  //這個函式直接就構成TIN了嘛？原理是什麼 直接宣告就構成TIN了？還有合理不合理啊？ 確實是直接構成TIN了！ 而且合法 也就是直接定義而且賦值了！
  Triangulation T(L.begin(), L.end());  
  T.is_valid();
  std::cout<<T.is_valid()<<endl;
  Triangulation::size_type n = T.number_of_vertices();
  // insertion from a vector :
  std::vector<Point> V(3);
  V[0] = Point(0,0,1);
  V[1] = Point(1,1,1);
  V[2] = Point(2,2,2);
  n = n + T.insert(V.begin(), V.end()); //這個函式既insert了這幾個點，而且return了幾個點。
  assert( n == 6 );       // 6 points have been inserted
  assert( T.is_valid() ); // checking validity of T
  Locate_type lt;
  int li, lj;
  Point p(0,0,0);
  Cell_handle c = T.locate(p, lt, li, lj); //
  // p is the vertex of c of index li :
  //If the k-face is a cell, li and lj have no meaning; if it is a facet (resp. vertex), 
  //li gives the index of the facet (resp. vertex) and lj has no meaning; if it is and edge, li and lj give the indices of its vertices.
  assert( lt == Triangulation::VERTEX );
  assert( c->vertex(li)->point() == p );
  Vertex_handle v = c->vertex( (li+1)&3 );
  // v is another vertex of c
  Cell_handle nc = c->neighbor(li);
  // nc = neighbor of c opposite to the vertex associated with p
  // nc must have vertex v :
  int nli;
  assert( nc->has_vertex( v, nli ) );
  // nli is the index of v in nc
  std::ofstream oFileT("output",std::ios::out);
  // writing file output;
  oFileT << T;
  Triangulation T1;
  std::ifstream iFileT("output",std::ios::in);
  // reading file output;
  iFileT >> T1;
  assert( T1.is_valid() );
  assert( T1.number_of_vertices() == T.number_of_vertices() );
  assert( T1.number_of_cells() == T.number_of_cells() );
  getchar();
  return 0;
}

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