ExtractEdges.cpp

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// Gmsh - Copyright (C) 1997-2022 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file in the Gmsh root directory for license information.
// Please report all issues on https://gitlab.onelab.info/gmsh/gmsh/issues.
 
#include "GmshConfig.h"
#include "GModel.h"
#include "ExtractEdges.h"
 
#if defined(HAVE_MESH)
#include "meshGFaceOptimize.h"
#endif
 
StringXNumber ExtractEdgesOptions_Number[] = {
  {GMSH_FULLRC, "Angle", nullptr, 40.},
  {GMSH_FULLRC, "IncludeBoundary", nullptr, 1.},
};
 
extern "C" {
GMSH_Plugin *GMSH_RegisterExtractEdgesPlugin()
{
  return new GMSH_ExtractEdgesPlugin();
}
}
 
std::string GMSH_ExtractEdgesPlugin::getHelp() const
{
  return "Plugin(ExtractEdges) extracts sharp edges "
         "from a triangular mesh.\n\n"
         "Plugin(ExtractEdges) creates one new view.";
}
 
int GMSH_ExtractEdgesPlugin::getNbOptions() const
{
  return sizeof(ExtractEdgesOptions_Number) / sizeof(StringXNumber);
}
 
StringXNumber *GMSH_ExtractEdgesPlugin::getOption(int iopt)
{
  return &ExtractEdgesOptions_Number[iopt];
}
 
#if defined(HAVE_MESH)
 
static void add_edge(edge_angle &ea, PViewDataList *data)
{
  data->SL.push_back(ea.v1->x());
  data->SL.push_back(ea.v2->x());
  data->SL.push_back(ea.v1->y());
  data->SL.push_back(ea.v2->y());
  data->SL.push_back(ea.v1->z());
  data->SL.push_back(ea.v2->z());
  data->SL.push_back(1.);
  data->SL.push_back(1.);
  data->NbSL++;
}
 
PView *GMSH_ExtractEdgesPlugin::execute(PView *v)
{
  std::vector<MTriangle *> elements;
  for(auto it = GModel::current()->firstFace();
      it != GModel::current()->lastFace(); ++it)
    elements.insert(elements.end(), (*it)->triangles.begin(),
                    (*it)->triangles.end());
 
  if(elements.empty()) {
    Msg::Error("No triangles in mesh to extract edges from");
    return nullptr;
  }
 
  PView *v2 = new PView();
  PViewDataList *data2 = getDataList(v2);
 
  e2t_cont adj;
  buildEdgeToTriangle(elements, adj);
  std::vector<edge_angle> edges_detected, edges_lonly;
  buildListOfEdgeAngle(adj, edges_detected, edges_lonly);
 
  double threshold = ExtractEdgesOptions_Number[0].def / 180. * M_PI;
  for(std::size_t i = 0; i < edges_detected.size(); i++) {
    if(edges_detected[i].angle <= threshold) break;
    add_edge(edges_detected[i], data2);
  }
 
  if(ExtractEdgesOptions_Number[1].def) {
    for(std::size_t i = 0; i < edges_lonly.size(); i++) {
      add_edge(edges_lonly[i], data2);
    }
  }
 
  data2->setName("ExtractEdges");
  data2->setFileName("ExtractEdges.pos");
  data2->finalize();
 
  return v2;
}
 
#else
 
PView *GMSH_ExtractEdgesPlugin::execute(PView *v)
{
  Msg::Error("Plugin(ExtractEdges) requires the mesh module");
  return v;
}
 
#endif