netgen/libsrc/occ/python_occ.cpp

#ifdef NG_PYTHON
#ifdef OCCGEOMETRY

#include <../general/ngpython.hpp>

#include <meshing.hpp>
#include <occgeom.hpp>

using namespace netgen;

namespace netgen
{
  extern std::shared_ptr<NetgenGeometry> ng_geometry;
}


DLL_HEADER void ExportNgOCC(py::module &m) 
{
  py::class_<OCCGeometry, shared_ptr<OCCGeometry>, NetgenGeometry> (m, "OCCGeometry", R"raw_string(Use LoadOCCGeometry to load the geometry from a *.step file.)raw_string")
    .def(py::init<>())
    .def("Heal",[](OCCGeometry & self, double tolerance, bool fixsmalledges, bool fixspotstripfaces, bool sewfaces, bool makesolids, bool splitpartitions)
         {
           self.tolerance = tolerance;
           self.fixsmalledges = fixsmalledges;
           self.fixspotstripfaces = fixspotstripfaces;
           self.sewfaces = sewfaces;
           self.makesolids = makesolids;
           self.splitpartitions = splitpartitions;

           self.HealGeometry();
           self.BuildFMap();
         },py::arg("tolerance")=1e-3, py::arg("fixsmalledges")=true, py::arg("fixspotstripfaces")=true, py::arg("sewfaces")=true, py::arg("makesolids")=true, py::arg("splitpartitions")=false,R"raw_string(Heal the OCCGeometry.)raw_string",py::call_guard<py::gil_scoped_release>())
    .def("_visualizationData", [] (shared_ptr<OCCGeometry> occ_geo)
         {
           std::vector<float> vertices;
           std::vector<int> trigs;
           std::vector<float> normals;
           std::vector<float> min = {std::numeric_limits<float>::max(),
                               std::numeric_limits<float>::max(),
                               std::numeric_limits<float>::max()};
           std::vector<float> max = {std::numeric_limits<float>::lowest(),
                               std::numeric_limits<float>::lowest(),
                               std::numeric_limits<float>::lowest()};
           std::vector<string> surfnames;
           auto box = occ_geo->GetBoundingBox();
           for(int i = 0; i < 3; i++)
             {
               min[i] = box.PMin()[i];
               max[i] = box.PMax()[i];
             }
           occ_geo->BuildVisualizationMesh(0.01);
           gp_Pnt2d uv;
           gp_Pnt pnt;
           gp_Vec n;
           gp_Pnt p[3];
           int count = 0;
           for (int i = 1; i <= occ_geo->fmap.Extent(); i++)
             {
               surfnames.push_back("occ_surface" + to_string(i));
               auto face = TopoDS::Face(occ_geo->fmap(i));
               auto surf = BRep_Tool::Surface(face);
               TopLoc_Location loc;
               BRepAdaptor_Surface sf(face, Standard_False);
               BRepLProp_SLProps prop(sf, 1, 1e-5);
               Handle(Poly_Triangulation) triangulation = BRep_Tool::Triangulation (face, loc);
               if (triangulation.IsNull())
                 cout << "cannot visualize face " << i << endl;
               trigs.reserve(trigs.size() + triangulation->NbTriangles()*4);
               vertices.reserve(vertices.size() + triangulation->NbTriangles()*3*3);
               normals.reserve(normals.size() + triangulation->NbTriangles()*3*3);
               for (int j = 1; j < triangulation->NbTriangles()+1; j++)
                 {
                   auto triangle = (triangulation->Triangles())(j);
                   for (int k = 1; k < 4; k++)
                     p[k-1] = (triangulation->Nodes())(triangle(k)).Transformed(loc);
                   for (int k = 1; k < 4; k++)
                     {
                       vertices.insert(vertices.end(),{float(p[k-1].X()), float(p[k-1].Y()), float(p[k-1].Z())});
                       trigs.insert(trigs.end(),{count, count+1, count+2,i});
                       count += 3;
                       uv = (triangulation->UVNodes())(triangle(k));
                       prop.SetParameters(uv.X(), uv.Y());
                       if (prop.IsNormalDefined())
                         n = prop.Normal();
                       else
                         {
                           gp_Vec a(p[0], p[1]);
                           gp_Vec b(p[0], p[2]);
                           n = b^a;
                         }
                       if (face.Orientation() == TopAbs_REVERSED) n*= -1;
                       normals.insert(normals.end(),{float(n.X()), float(n.Y()), float(n.Z())});
                     }
                 }
             }
            py::gil_scoped_acquire ac;
            py::dict res;
            py::list snames;
            for(auto name : surfnames)
              snames.append(py::cast(name));
            res["vertices"] = MoveToNumpy(vertices);
            res["triangles"] = MoveToNumpy(trigs);
            res["normals"] = MoveToNumpy(normals);
            res["surfnames"] = snames;
            res["min"] = MoveToNumpy(min);
            res["max"] = MoveToNumpy(max);
            return res;
         }, py::call_guard<py::gil_scoped_release>())
      ;
    m.def("LoadOCCGeometry",FunctionPointer([] (const string & filename)
           {
             cout << "load OCC geometry";
             ifstream ist(filename);
             OCCGeometry * instance = new OCCGeometry();
             instance = LoadOCC_STEP(filename.c_str());
             ng_geometry = shared_ptr<OCCGeometry>(instance, NOOP_Deleter);
             return ng_geometry;
           }),py::call_guard<py::gil_scoped_release>());
  m.def("GenerateMesh", FunctionPointer([] (shared_ptr<OCCGeometry> geo, MeshingParameters &param)
					{
					  auto mesh = make_shared<Mesh>();
					  SetGlobalMesh(mesh);
					  mesh->SetGeometry(geo);
					  ng_geometry = geo;

					  try
					    {
					      geo->GenerateMesh(mesh,param);
					    }
					  catch (NgException ex)
					    {
					      cout << "Caught NgException: " << ex.What() << endl;
					    }
					  return mesh;
					}),py::call_guard<py::gil_scoped_release>())
    ;
}

PYBIND11_MODULE(libNgOCC, m) {
  ExportNgOCC(m);
}

#endif // OCCGEOMETRY
#endif // NG_PYTHON