1. /* geodoer
  2.  @Time: 2021/8/20
  3.  @desc: 多个表面模型，合并成一个
  4.  */
  5. #include <CGAL/Exact_predicates_exact_constructions_kernel.h>
  6. #include <CGAL/Polyhedron_3.h>
  7. #include <CGAL/Surface_mesh.h>
  8. #include <CGAL/Nef_polyhedron_3.h>
  9. #include <CGAL/boost/graph/convert_nef_polyhedron_to_polygon_mesh.h>
  11. #include<vector>
  12. #include<QDir>
  13. #include<QTime>
  15. //将PolygonSoup转PolygonMesh
  16. #include <CGAL/Polygon_mesh_processing/orient_polygon_soup.h>
  17. #include <CGAL/Polygon_mesh_processing/polygon_soup_to_polygon_mesh.h>
  18. #include <CGAL/Polygon_mesh_processing/orientation.h>
  19. #include <CGAL/IO/polygon_soup_io.h>
  21. typedef CGAL::Exact_predicates_exact_constructions_kernel Exact_kernel;
  22. typedef Exact_kernel::Point_3 Point;
  23. typedef CGAL::Polyhedron_3<Exact_kernel> Polyhedron;
  24. typedef CGAL::Surface_mesh<Exact_kernel::Point_3> Surface_mesh;
  25. typedef CGAL::Nef_polyhedron_3<Exact_kernel> Nef_polyhedron;
  27. using namespace std;
  29. Polyhedron read_off(const std::string& dir, const std::string& fn)
  30. {
  31.     auto fp = dir + "\\" + fn;
  33.     //表面模型不一定是PolygonMesh，只是PolygonSoup
  34.     //所以要当成PolygonSoup读入
  35.     std::vector<Point> points;
  36.     std::vector<std::vector<std::size_t> > polygons;
  38.     if (!CGAL::IO::read_polygon_soup(fp, points, polygons) || points.empty())
  39.     {
  40.         throw "Cannot open file ";
  41.     }
  43.     //转换成PolygonMesh
  44.     CGAL::Polygon_mesh_processing::orient_polygon_soup(points, polygons);
  46.     Polyhedron mesh;
  47.     CGAL::Polygon_mesh_processing::polygon_soup_to_polygon_mesh(points, polygons, mesh);
  48.     return mesh;
  49. }
  51. void save(const Nef_polyhedron& nef, const std::string& outfp)
  52. {
  53.     Surface_mesh output;
  54.     CGAL::convert_nef_polyhedron_to_polygon_mesh(nef, output);
  55.     std::ofstream out;
  56.     out.open(outfp);
  57.     out << output;
  58.     out.close();
  59. }
  61. void printTime(const QTime& time)
  62. {
  63.     int time_Diff = time.elapsed(); //返回从上次start()或restart()开始以来的时间差，单位ms
  64.     //以下方法是将ms转为s
  65.     float f = time_Diff / 1000.0;
  66.     QString tr_timeDiff = QString("%1").arg(f); //float->QString
  67.     std::cout << tr_timeDiff.toStdString() << "s" << std::endl;
  68. }
  70. int main()
  71. {
  72.     //找到dirPath下的off，然后融合
  73.     QString dirPath = R"(F:\00data\00work\GridToBrep20210819\data\wmodeler)";
  74.     QString outFp = dirPath + "\\out.off";
  76.     QTime time;
  77.     time.start(); //开始计时，以ms为单位
  79.     QDir dir(dirPath);
  80.     dir.setNameFilters(QStringList() << "*.off");
  81.     QStringList fileNames = dir.entryList();
  83.     if (fileNames.size() == 0)
  84.     {
  85.         return 1;
  86.     }
  88.     auto first = read_off(dirPath.toStdString(), fileNames[0].toStdString());
  89.     Nef_polyhedron nef(
  90.         first
  91.     );
  93.     int errorCnt = 0;
  95.     std::cout << "个数\t时间(s)" << std::endl;
  97.     //for (int i = 1; i < fileNames.size(); ++i)
  98.     for (int i = 1; i < 1000; ++i)
  99.     {
  100.         auto fn = fileNames[i];
  101.         auto mesh = read_off(dirPath.toStdString(), fn.toStdString());
  103.         try
  104.         {
  105.             Nef_polyhedron tmp(mesh);
  106.             nef = nef + tmp;
  107.         }
  108.         catch (...)
  109.         {
  110.             errorCnt++;
  111.         }
  113.         if (i % 100 == 1)
  114.         {
  115.             save(nef, outFp.toStdString());
  117.             cout << i << '\t';
  118.             printTime(time);
  119.         }
  120.     }
  122.     save(nef, outFp.toStdString());
  123.     printTime(time);
  124. }

测试

N个长方体的融合
image.png