VTK/Examples/Cxx/PolyData/CellPointNeighbors

#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkPolyData.h>
#include <vtkIdList.h>
#include <vtkCell.h>
#include <vtkTriangleFilter.h>
#include <vtkDataSetMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkIdTypeArray.h>
#include <vtkSelectionNode.h>
#include <vtkSelection.h>
#include <vtkExtractSelection.h>
#include <vtkProperty.h>
 
#include <list>
 
int main(int, char *[])
{
  //Create a sphere
  vtkSmartPointer<vtkSphereSource> sphereSource =
      vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->Update();
 
  vtkSmartPointer<vtkTriangleFilter> triangleFilter =
    vtkSmartPointer<vtkTriangleFilter>::New();
  triangleFilter->SetInputConnection(sphereSource->GetOutputPort());
  triangleFilter->Update();
 
  // Find all cells connected to point 0
  vtkIdType cellId = 0;
 
  vtkSmartPointer<vtkIdList> cellPointIds =
    vtkSmartPointer<vtkIdList>::New();
  triangleFilter->GetOutput()->GetCellPoints(cellId, cellPointIds);
 
  // neighbor cells may be listed multiple times
  // use std::set instead of std::list if you want a unique list of neighbors
  std::list<vtkIdType> neighbors;
 
  for(vtkIdType i = 0; i < cellPointIds->GetNumberOfIds(); i++)
    {
    vtkSmartPointer<vtkIdList> idList =
      vtkSmartPointer<vtkIdList>::New();
    idList->InsertNextId(cellPointIds->GetId(i));
 
    //get the neighbors of the cell
    vtkSmartPointer<vtkIdList> neighborCellIds =
      vtkSmartPointer<vtkIdList>::New();
 
    triangleFilter->GetOutput()->GetCellNeighbors(cellId, idList, neighborCellIds);
 
    for(vtkIdType j = 0; j < neighborCellIds->GetNumberOfIds(); j++)
      {
      neighbors.push_back(neighborCellIds->GetId(j));
      }
 
    }
 
  std::cout << "Point neighbor ids are: " << std::endl;
 
  for(std::list<vtkIdType>::iterator it1 = neighbors.begin(); it1 != neighbors.end(); it1++)
    {
    std::cout << " " << *it1;
    }
  std::cout << std::endl;
 
 
  vtkSmartPointer<vtkDataSetMapper> sphereMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
  sphereMapper->SetInputConnection(sphereSource->GetOutputPort());
  vtkSmartPointer<vtkActor> sphereActor =
    vtkSmartPointer<vtkActor>::New();
  sphereActor->SetMapper(sphereMapper);
  sphereActor->GetProperty()->SetEdgeColor(0, 0, 0);
  sphereActor->GetProperty()->EdgeVisibilityOn();
 
  vtkSmartPointer<vtkDataSetMapper> mainCellMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
 
  vtkSmartPointer<vtkDataSetMapper> neighborCellsMapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
 
  // Create a dataset with the cell of interest
  {
    vtkSmartPointer<vtkIdTypeArray> ids =
        vtkSmartPointer<vtkIdTypeArray>::New();
    ids->SetNumberOfComponents(1);
    ids->InsertNextValue(cellId);
 
    vtkSmartPointer<vtkSelectionNode> selectionNode =
      vtkSmartPointer<vtkSelectionNode>::New();
    selectionNode->SetFieldType(vtkSelectionNode::CELL);
    selectionNode->SetContentType(vtkSelectionNode::INDICES);
    selectionNode->SetSelectionList(ids);
 
    vtkSmartPointer<vtkSelection> selection =
        vtkSmartPointer<vtkSelection>::New();
    selection->AddNode(selectionNode);
 
    vtkSmartPointer<vtkExtractSelection> extractSelection =
        vtkSmartPointer<vtkExtractSelection>::New();
    extractSelection->SetInputConnection(0, sphereSource->GetOutputPort());
#if VTK_MAJOR_VERSION <= 5
    extractSelection->SetInput(1, selection);
#else
    extractSelection->SetInputData(1, selection);
#endif
    extractSelection->Update();
 
    mainCellMapper->SetInputConnection(extractSelection->GetOutputPort());
 
  }
 
  vtkSmartPointer<vtkActor> mainCellActor =
    vtkSmartPointer<vtkActor>::New();
  mainCellActor->SetMapper(mainCellMapper);
  mainCellActor->GetProperty()->SetColor(1,0,0);
 
  // Create a dataset with the neighbor cells
  {
    vtkSmartPointer<vtkIdTypeArray> ids =
        vtkSmartPointer<vtkIdTypeArray>::New();
    ids->SetNumberOfComponents(1);
    for(std::list<vtkIdType>::iterator it1 = neighbors.begin(); it1 != neighbors.end(); it1++)
      {
      ids->InsertNextValue(*it1);
      }
 
    vtkSmartPointer<vtkSelectionNode> selectionNode =
      vtkSmartPointer<vtkSelectionNode>::New();
    selectionNode->SetFieldType(vtkSelectionNode::CELL);
    selectionNode->SetContentType(vtkSelectionNode::INDICES);
    selectionNode->SetSelectionList(ids);
 
    vtkSmartPointer<vtkSelection> selection =
        vtkSmartPointer<vtkSelection>::New();
    selection->AddNode(selectionNode);
 
    vtkSmartPointer<vtkExtractSelection> extractSelection =
        vtkSmartPointer<vtkExtractSelection>::New();
    extractSelection->SetInputConnection(0, sphereSource->GetOutputPort());
#if VTK_MAJOR_VERSION <= 5
    extractSelection->SetInput(1, selection);
#else
    extractSelection->SetInputData(1, selection);
#endif
    extractSelection->Update();
 
    neighborCellsMapper->SetInputConnection(extractSelection->GetOutputPort());
 
  }
 
  vtkSmartPointer<vtkActor> neighborCellsActor =
    vtkSmartPointer<vtkActor>::New();
  neighborCellsActor->SetMapper(neighborCellsMapper);
  neighborCellsActor->GetProperty()->SetColor(0,1,0);
 
  //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(mainCellActor);
  renderer->AddActor(neighborCellsActor);
  renderer->SetBackground(.3, .2, .1); // Background color dark red
 
  //Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();
 
  return EXIT_SUCCESS;
}