Method RequestData

Filters/Modeling/vtkSelectPolyData.cxx:257–395

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//------------------------------------------------------------------------------
int vtkSelectPolyData::RequestData(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the input and output objects
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkPolyData* input = vtkPolyData::SafeDownCast(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData* output = vtkPolyData::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // Initialize and check data
  vtkDebugMacro(<< "Selecting data...");

  this->GetUnselectedOutput()->Initialize();
  this->GetSelectionEdges()->Initialize();

  // CHeck if inputs are valid
  if (input->GetNumberOfPoints() < 1)
  {
    vtkErrorMacro("Input contains no points");
    return 1;
  }
  vtkIdType numLoopPts;
  if (this->Loop == nullptr || (numLoopPts = this->Loop->GetNumberOfPoints()) < 3)
  {
    vtkErrorMacro("Please define a loop with at least three points");
    return 1;
  }

  // Convert to triangle mesh. All further computations are done on the triangulated mesh.
  vtkSmartPointer<vtkPolyData> triMesh;
  {
    vtkNew<vtkTriangleFilter> tf;
    tf->SetInputData(input);
    tf->PassLinesOff();
    tf->PassVertsOff();
    tf->SetContainerAlgorithm(this);
    tf->Update();
    triMesh = tf->GetOutput();
  }
  vtkCellArray* inPolys = triMesh->GetPolys();
  if (inPolys->GetNumberOfCells() < 1)
  {
    vtkErrorMacro("This filter operates on surface primitives");
    return 1;
  }

  // Create a mesh that only contains points and polys
  // (probably to avoid potential interference of other cell types)
  // and links are computed (so that neighbors can be retrieved).
  vtkNew<vtkPolyData> mesh;
  vtkPoints* inPts = triMesh->GetPoints();
  mesh->SetPoints(inPts);
  mesh->SetPolys(inPolys);
  mesh->BuildLinks(); // to do neighborhood searching
  vtkIdType numCells = mesh->GetNumberOfCells();

  // Get a list of point IDs of the mesh that forms a continuous closed loop
  vtkNew<vtkIdList> edgePointIds;