CellCentersDemo

#include <vtkSmartPointer.h>
#include <vtkCellCenters.h>

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkGlyph3DMapper.h>

#include <vtkBYUReader.h>
#include <vtkOBJReader.h>
#include <vtkPLYReader.h>
#include <vtkPolyDataReader.h>
#include <vtkSTLReader.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkSphereSource.h>
#include <vtksys/SystemTools.hxx>

#include <vtkSphereSource.h>
#include <vtkNamedColors.h>
#include <vtkColor.h>

#include <vector>
#include <algorithm>

namespace
{
vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
}

int main (int argc, char *argv[])
{
  // Define the colors used in the example
  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();
  vtkColor3d actorColor      = colors->GetColor3d("Banana");
  vtkColor3d pointActorColor = colors->GetColor3d("Peacock");
  vtkColor3d backgroundColor = colors->GetColor3d("Silver");

  // Read the polydata
  vtkSmartPointer<vtkPolyData> polyData =
    ReadPolyData(argc > 1 ? argv[1] : "");

  std::vector<double> bounds(6);;
  polyData->GetBounds(&bounds[0]);
  std::vector<double> range(3);
  for (int i = 0; i < 3; ++i)
  {
    range[i] = bounds[2*i + 1] - bounds[2*i];
  }
  std::cout << "Range: "
            << range[0] << ", "
            << range[1] << ", "
            << range[2] << std::endl;

  vtkSmartPointer<vtkCellCenters> centers =
    vtkSmartPointer<vtkCellCenters>::New();
  centers->SetInputData(polyData);

  auto maxRange = std::max_element(range.begin(), range.end());
  double radius = *maxRange * .0025;
  vtkSmartPointer<vtkSphereSource> sphere =
    vtkSmartPointer<vtkSphereSource>::New();
  sphere->SetPhiResolution(11);
  sphere->SetThetaResolution(11);
  sphere->SetRadius(radius);

  vtkSmartPointer<vtkGlyph3DMapper> pointMapper =
    vtkSmartPointer<vtkGlyph3DMapper>::New();
  pointMapper->SetInputConnection(centers->GetOutputPort());
  pointMapper->SetSourceConnection(sphere->GetOutputPort());

  vtkSmartPointer<vtkActor> pointActor =
    vtkSmartPointer<vtkActor>::New();
  pointActor->SetMapper(pointMapper);
  pointActor->GetProperty()->SetColor(pointActorColor.GetData());

  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputData(polyData);

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(actorColor.GetData());
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetInterpolationToFlat();

  // Setup render window, renderer, 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);
  renderer->AddActor(actor);
  renderer->AddActor(pointActor);

  renderer->ResetCamera();
  renderer->GetActiveCamera()->Azimuth(30);
  renderer->GetActiveCamera()->Elevation(30);
  renderer->GetActiveCamera()->Dolly(1.5);
  renderer->ResetCameraClippingRange();
  renderer->SetBackground(backgroundColor.GetData());

  renderWindow->SetSize(640, 480);
  renderWindow->Render();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

namespace
{
vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
{
  vtkSmartPointer<vtkPolyData> polyData;
  std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
  if (extension == ".ply")
  {
    vtkSmartPointer<vtkPLYReader> reader =
      vtkSmartPointer<vtkPLYReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtp")
  {
    vtkSmartPointer<vtkXMLPolyDataReader> reader =
      vtkSmartPointer<vtkXMLPolyDataReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".obj")
  {
    vtkSmartPointer<vtkOBJReader> reader =
      vtkSmartPointer<vtkOBJReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".stl")
  {
    vtkSmartPointer<vtkSTLReader> reader =
      vtkSmartPointer<vtkSTLReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtk")
  {
    vtkSmartPointer<vtkPolyDataReader> reader =
      vtkSmartPointer<vtkPolyDataReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".g")
  {
    vtkSmartPointer<vtkBYUReader> reader =
      vtkSmartPointer<vtkBYUReader>::New();
    reader->SetGeometryFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else
  {
    vtkSmartPointer<vtkSphereSource> source =
      vtkSmartPointer<vtkSphereSource>::New();
    source->Update();
    polyData = source->GetOutput();
  }
  return polyData;
}
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(CellCentersDemo)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersGeneral
  vtkFiltersSources
  vtkIOGeometry
  vtkIOLegacy
  vtkIOPLY
  vtkIOXML
  vtkInteractionStyle
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping CellCentersDemo: ${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(CellCentersDemo MACOSX_BUNDLE CellCentersDemo.cxx )
  target_link_libraries(CellCentersDemo PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(CellCentersDemo MACOSX_BUNDLE CellCentersDemo.cxx )
  target_link_libraries(CellCentersDemo PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS CellCentersDemo
    MODULES ${VTK_LIBRARIES}
    )
endif () 

cd CellCentersDemo/build 

cmake ..

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

make

./CellCentersDemo