# CellTypeSource

VTKExamples/Cxx/GeometricObjects/CellTypeSource

### Description

This example uses vtkCellTypeSource to generate a vtkUnstructuredGrid. If a cell does not fill a rectangular area or volume, then multiple cells will be generated. For example, a vtkTetra requires 12 cells to fill a cube. A vtkTriangle requires two cells to fill a square. vtkCellTypeSource generates a uniform set of coordinates. The example perturbs those coordinates to illustrate the results of the vtkTessellatorFilter. Also, each cell is passed through vtkShrinkFilter to help identify the cells. Each generated cell also has a unique color.

The example takes an optonal argument, a vtkCell name.

For example, to generate vtkTriangles, run

`CellTypeSource` vtkTriangle

Other Languages

See (Python)

### Code

CellTypeSource.cxx

    #include <vtkActor.h>
    #include <vtkActor2D.h>
    #include <vtkCamera.h>
    #include <vtkCellData.h>
    #include <vtkCellType.h>
    #include <vtkCellTypes.h>
    #include <vtkCellTypeSource.h>
    #include <vtkColorSeries.h>
    #include <vtkDataSetMapper.h>
    #include <vtkIntArray.h>
    #include <vtkLookupTable.h>
    #include <vtkMath.h>
    #include <vtkMinimalStandardRandomSequence.h>
    #include <vtkNamedColors.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkShrinkFilter.h>
    #include <vtkSmartPointer.h>
    #include <vtkTessellatorFilter.h>
    #include <vtkTextMapper.h>
    #include <vtkTextProperty.h>
    #include <vtkUnstructuredGrid.h>

    #include <map>

    int main (int argc, char *argv[])
    {
      std::string cellName = "vtkTetra";
      if (argc > 1)
      {
        cellName = std::string(argv[1]);
      }

      // Store cell class names in a map
      std::map<std::string,int> cellMap;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_LINE)] =
        VTK_LINE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_EDGE)] =
        VTK_QUADRATIC_EDGE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_CUBIC_LINE)] =
        VTK_CUBIC_LINE;

      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_TRIANGLE)] =
        VTK_TRIANGLE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_TRIANGLE)] =
        VTK_QUADRATIC_TRIANGLE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUAD)] =
        VTK_QUAD;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_QUAD)] =
        VTK_QUADRATIC_QUAD;

      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_TETRA)] =
        VTK_TETRA;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_HEXAHEDRON)] =
        VTK_HEXAHEDRON;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_WEDGE)] =
        VTK_WEDGE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_PYRAMID)] =
        VTK_PYRAMID;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_WEDGE)] =
        VTK_QUADRATIC_WEDGE;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_PYRAMID)] =
        VTK_QUADRATIC_PYRAMID;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_HEXAHEDRON)] =
        VTK_QUADRATIC_HEXAHEDRON;
      cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_TETRA)] =
        VTK_QUADRATIC_TETRA;

      if (cellMap[std::string(cellName)] == 0)
        {
          std::cout << "Cell type " << cellName << " is not supported." << std::endl;
          return EXIT_FAILURE;
        }
      vtkSmartPointer<vtkCellTypeSource> source =
        vtkSmartPointer<vtkCellTypeSource>::New();
      source->SetCellType(cellMap[cellName]);
      source->Update();
      std::cout << "Cell: "
                << cellName << std::endl;

      vtkPoints *originalPoints = source->GetOutput()->GetPoints();
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->SetNumberOfPoints(source->GetOutput()->GetNumberOfPoints());
      vtkSmartPointer<vtkMinimalStandardRandomSequence> rng =
        vtkSmartPointer<vtkMinimalStandardRandomSequence>::New();
      rng->SetSeed(5070); // for testing
      for (auto i = 0; i <points->GetNumberOfPoints(); ++i)
      {
        double perturbation[3];
        for (auto j = 0; j < 3; ++j)
        {
          rng->Next();
          perturbation[j] = rng->GetRangeValue(-0.1,0.1);
        }
        double currentPoint[3];
        originalPoints->GetPoint(i, currentPoint);
        points->SetPoint(i,currentPoint[0] + perturbation[0],
                           currentPoint[1] + perturbation[1],
                           currentPoint[2] + perturbation[2]);
      }
      source->GetOutput()->SetPoints(points);

      int numCells = source->GetOutput()->GetNumberOfCells();
      std::cout << "Number of cells: " << numCells << std::endl;
      vtkSmartPointer<vtkIntArray> idArray =
        vtkSmartPointer<vtkIntArray>::New();
      idArray->SetNumberOfTuples(numCells);
      for (auto i = 0; i < numCells; ++i)
      {
        idArray->InsertTuple1(i, i + 1);
      }
      idArray->SetName("Ids");
      source->GetOutput()->GetCellData()->AddArray(idArray);
      source->GetOutput()->GetCellData()->SetActiveScalars("Ids");

      vtkSmartPointer<vtkShrinkFilter> shrink =
        vtkSmartPointer<vtkShrinkFilter>::New();
      shrink->SetInputConnection(source->GetOutputPort());
      shrink->SetShrinkFactor(.8);

      vtkSmartPointer<vtkTessellatorFilter> tessellate =
        vtkSmartPointer<vtkTessellatorFilter>::New();
      tessellate->SetInputConnection(shrink->GetOutputPort());
      tessellate->SetMaximumNumberOfSubdivisions(3);

      // Create a lookup table to map cell data to colors
      vtkSmartPointer<vtkNamedColors> namedColors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkLookupTable> lut =
        vtkSmartPointer<vtkLookupTable>::New();

      vtkSmartPointer<vtkColorSeries> colorSeries =
        vtkSmartPointer<vtkColorSeries>::New();
      int seriesEnum = colorSeries->BREWER_QUALITATIVE_SET3;;
      colorSeries->SetColorScheme(seriesEnum);
      colorSeries->BuildLookupTable(lut, colorSeries->ORDINAL);

      // Fill in a few known colors, the rest will be generated if needed
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      //Create a mapper and actor
      vtkSmartPointer<vtkDataSetMapper> mapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      mapper->SetInputConnection(source->GetOutputPort());
      mapper->SetInputConnection(shrink->GetOutputPort());
      mapper->SetScalarRange(0, numCells + 1);
      mapper->SetLookupTable(lut);
      mapper->SetScalarModeToUseCellData();
      mapper->SetResolveCoincidentTopologyToPolygonOffset();
      if (source->GetCellType() == VTK_QUADRATIC_PYRAMID ||
          source->GetCellType() == VTK_QUADRATIC_WEDGE)
      {
        mapper->SetInputConnection(shrink->GetOutputPort());
      }
      else
      {
        mapper->SetInputConnection(tessellate->GetOutputPort());
      }
      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->EdgeVisibilityOn();
    //  actor->GetProperty()->SetLineWidth(3);

      vtkSmartPointer<vtkTextProperty> textProperty =
        vtkSmartPointer<vtkTextProperty>::New();
      textProperty->SetFontSize(20);
      textProperty->SetJustificationToCentered();
      textProperty->SetColor(colors->GetColor3d("Lamp_Black").GetData());

      vtkSmartPointer<vtkTextMapper> textMapper =
        vtkSmartPointer<vtkTextMapper>::New();
      textMapper->SetInput(cellName.c_str());
      textMapper->SetTextProperty(textProperty);

      vtkSmartPointer<vtkActor2D> textActor =
        vtkSmartPointer<vtkActor2D>::New();
      textActor->SetMapper(textMapper);
      textActor->SetPosition(320, 20);

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

      //Add the actors to the scene
      renderer->AddViewProp(textActor);
      renderer->AddActor(actor);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());

      renderer->ResetCamera();
      renderer->GetActiveCamera()->Azimuth(30);
      renderer->GetActiveCamera()->Elevation(30);
      renderer->ResetCameraClippingRange();

      //Render and interact
      renderWindow->SetSize(640, 480);
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(CellTypeSource)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersGeneral
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping CellTypeSource: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(CellTypeSource MACOSX_BUNDLE CellTypeSource.cxx )
      target_link_libraries(CellTypeSource PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(CellTypeSource MACOSX_BUNDLE CellTypeSource.cxx )
      target_link_libraries(CellTypeSource PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS CellTypeSource
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build CellTypeSource

Click here to download CellTypeSource and its CMakeLists.txt file. Once the tarball CellTypeSource.tar has been downloaded and extracted,

    cd CellTypeSource/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./CellTypeSource

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.