[vtkusers] vtkPolyData::GetPointCells segmentation fault

[Miguel Sotaquirá]

Hi!

I'm trying to build the 1-ring neighborhood of each point on a mesh by using
a modified version of the VertexConnectivity example
http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/VertexConnectivity),
actually is the same version, the only thing I've changed is the source
(instead of a "SphereSource" I'm using a vtkXMLPolyDataReader). See the my
code below...

My mesh has 40938 points, and the code behaves well until it arrives to the
point 38454. At this point I always get a run-time error "Segmentation
fault". I've managed to isolate the problem and I'm pretty sure it happens
when calling the function:

mesh->GetPointCells(id, cellIdList),

where "id" is, in my case, 38454...

I've also tried with other meshes (with different number of points) and I
ALWAYS get the same "Segmentation Fault" error... The strangest thing is
that when implementing the original example (using the sphere) I do not get
any errors at all!

Am I doing something wrong? There might be a problem with my meshes? It
might be a bug in vtkPolyData::GetPointCells()???

Heres the code:

vtkSmartPointer<vtkIdList> GetConnectedVertices(vtkSmartPointer<vtkPolyData>
mesh, int id);

int main(int, char* argv[])
{
  // vtkSmartPointer<vtkSphereSource> sphereSource =
  //       vtkSmartPointer<vtkSphereSource>::New();
  //   sphereSource->Update();
 vtkSmartPointer<vtkXMLPolyDataReader> sphereSource =
vtkSmartPointer<vtkXMLPolyDataReader>::New();
sphereSource->SetFileName(argv[1]);
sphereSource->Update();

  vtkSmartPointer<vtkTriangleFilter> triangleFilter =
      vtkSmartPointer<vtkTriangleFilter>::New();
  triangleFilter->SetInputConnection(sphereSource->GetOutputPort());
  triangleFilter->Update();

  vtkSmartPointer<vtkExtractEdges> extractEdges =
    vtkSmartPointer<vtkExtractEdges>::New();
  extractEdges->SetInputConnection(triangleFilter->GetOutputPort());
  extractEdges->Update();

  vtkSmartPointer<vtkPolyData> mesh = extractEdges->GetOutput();

  vtkSmartPointer<vtkIdList> connectedVertices = GetConnectedVertices(mesh,
38455);

  vtkSmartPointer<vtkIdTypeArray> ids =
    vtkSmartPointer<vtkIdTypeArray>::New();
  ids->SetNumberOfComponents(1);

  std::cout << "Connected vertices: ";
  for(vtkIdType i = 0; i < connectedVertices->GetNumberOfIds(); i++)
    {
    std::cout << connectedVertices->GetId(i) << " ";
    ids->InsertNextValue(connectedVertices->GetId(i));
    }
  std::cout << std::endl;

  vtkSmartPointer<vtkDataSetMapper> connectedVertexMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();

  {
    vtkSmartPointer<vtkSelectionNode> selectionNode =
      vtkSmartPointer<vtkSelectionNode>::New();
    selectionNode->SetFieldType(vtkSelectionNode::POINT);
    selectionNode->SetContentType(vtkSelectionNode::INDICES);
    selectionNode->SetSelectionList(ids);

    vtkSmartPointer<vtkSelection> selection =
        vtkSmartPointer<vtkSelection>::New();
    selection->AddNode(selectionNode);

    vtkSmartPointer<vtkExtractSelection> extractSelection =
        vtkSmartPointer<vtkExtractSelection>::New();

    extractSelection->SetInput(0, extractEdges->GetOutput());
    extractSelection->SetInput(1, selection);
    extractSelection->Update();

    vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter =
      vtkSmartPointer<vtkVertexGlyphFilter>::New();
    glyphFilter->SetInputConnection(extractSelection->GetOutputPort());
    glyphFilter->Update();

    connectedVertexMapper->SetInputConnection(glyphFilter->GetOutputPort());
  }

  vtkSmartPointer<vtkActor> connectedVertexActor =
    vtkSmartPointer<vtkActor>::New();
  connectedVertexActor->SetMapper(connectedVertexMapper);
  connectedVertexActor->GetProperty()->SetColor(1,0,0);
  connectedVertexActor->GetProperty()->SetPointSize(5);

  vtkSmartPointer<vtkDataSetMapper> queryVertexMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();

  {
    vtkSmartPointer<vtkIdTypeArray> ids =
      vtkSmartPointer<vtkIdTypeArray>::New();
    ids->SetNumberOfComponents(1);
    ids->InsertNextValue(0);

    vtkSmartPointer<vtkSelectionNode> selectionNode =
      vtkSmartPointer<vtkSelectionNode>::New();
    selectionNode->SetFieldType(vtkSelectionNode::POINT);
    selectionNode->SetContentType(vtkSelectionNode::INDICES);
    selectionNode->SetSelectionList(ids);

    vtkSmartPointer<vtkSelection> selection =
        vtkSmartPointer<vtkSelection>::New();
    selection->AddNode(selectionNode);

    vtkSmartPointer<vtkExtractSelection> extractSelection =
        vtkSmartPointer<vtkExtractSelection>::New();

    extractSelection->SetInput(0, extractEdges->GetOutput());
    extractSelection->SetInput(1, selection);
    extractSelection->Update();

    vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter =
      vtkSmartPointer<vtkVertexGlyphFilter>::New();
    glyphFilter->SetInputConnection(extractSelection->GetOutputPort());
    glyphFilter->Update();

    queryVertexMapper->SetInputConnection(glyphFilter->GetOutputPort());
  }

  vtkSmartPointer<vtkActor> queryVertexActor =
    vtkSmartPointer<vtkActor>::New();
  queryVertexActor->SetMapper(queryVertexMapper);
  queryVertexActor->GetProperty()->SetColor(0,1,0);
  queryVertexActor->GetProperty()->SetPointSize(5);

  vtkSmartPointer<vtkDataSetMapper> sphereMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
  sphereMapper->SetInputConnection(extractEdges->GetOutputPort());
  vtkSmartPointer<vtkActor> sphereActor =
    vtkSmartPointer<vtkActor>::New();
  sphereActor->SetMapper(sphereMapper);

    //Create a renderer, render window, and interactor
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  //Add the actors to the scene
  renderer->AddActor(sphereActor);
  renderer->AddActor(queryVertexActor);
  renderer->AddActor(connectedVertexActor);
  renderer->SetBackground(.3, .2, .1); // Background color dark red

  //Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

vtkSmartPointer<vtkIdList> GetConnectedVertices(vtkSmartPointer<vtkPolyData>
mesh, int id)
{
  vtkSmartPointer<vtkIdList> connectedVertices =
      vtkSmartPointer<vtkIdList>::New();

  //get all cells that vertex 'id' is a part of
  vtkSmartPointer<vtkIdList> cellIdList =
      vtkSmartPointer<vtkIdList>::New();
  mesh->GetPointCells(id, cellIdList);

  /*
  cout << "Vertex 0 is used in cells ";
  for(vtkIdType i = 0; i < cellIdList->GetNumberOfIds(); i++)
    {
    cout << cellIdList->GetId(i) << ", ";
    }
  cout << endl;
  */

  for(vtkIdType i = 0; i < cellIdList->GetNumberOfIds(); i++)
    {
    //cout << "id " << i << " : " << cellIdList->GetId(i) << endl;

    vtkSmartPointer<vtkIdList> pointIdList =
      vtkSmartPointer<vtkIdList>::New();
    mesh->GetCellPoints(cellIdList->GetId(i), pointIdList);

    //cout << "End points are " << pointIdList->GetId(0) << " and " <<
pointIdList->GetId(1) << endl;

    if(pointIdList->GetId(0) != id)
      {
      //cout << "Connected to " << pointIdList->GetId(0) << endl;
      connectedVertices->InsertNextId(pointIdList->GetId(0));
      }
    else
      {
      //cout << "Connected to " << pointIdList->GetId(1) << endl;
      connectedVertices->InsertNextId(pointIdList->GetId(1));
      }
    }

  return connectedVertices;
}

Thanks!

Miguel
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