# PolyDataPointSampler

VTKExamples/Cxx/PolyData/PolyDataPointSampler

### Description

Original points are yellow and added points are red.

This example uses the Torso.vtp dataset.

### Code

PolyDataPointSampler.cxx

    #include <vtkVersion.h>

    #include <vtkSmartPointer.h>
    #include <vtkPolyDataPointSampler.h>
    #include <vtkPLYReader.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkOBJReader.h>
    #include <vtkSTLReader.h>
    #include <vtkPointSource.h>

    #include <vtkSphereSource.h>
    #include <vtkGlyph3D.h>

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

    #include <vtksys/SystemTools.hxx>

    static vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);

    int main (int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");;

      double bounds[6];
      polyData->GetBounds(bounds);
      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;
      std::cout << "# of original points: " << polyData->GetNumberOfPoints() << std::endl;
      vtkSmartPointer<vtkPolyDataPointSampler> sample =
        vtkSmartPointer<vtkPolyDataPointSampler>::New();
    #if VTK_MAJOR_VERSION <= 5
      sample->SetInput(polyData);
    #else
      sample->SetInputData(polyData);
    #endif
      sample->SetDistance(range[0] / 50);
      sample->Update();
      std::cout << "# of points after sampling: " << sample->GetOutput()->GetNumberOfPoints() << std::endl;

    ///
      double radius = range[0] * .01;
      vtkSmartPointer<vtkSphereSource> originalSource =
        vtkSmartPointer<vtkSphereSource>::New();
      originalSource->SetRadius(radius);

      vtkSmartPointer<vtkGlyph3D> originalGlyph3D =
        vtkSmartPointer<vtkGlyph3D>::New();
    #if VTK_MAJOR_VERSION <= 5
      originalGlyph3D->SetInput(polyData);
    #else
      originalGlyph3D->SetInputData(polyData);
    #endif
      originalGlyph3D->SetSourceConnection(originalSource->GetOutputPort());
      originalGlyph3D->ScalingOff();
      originalGlyph3D->Update();
      vtkSmartPointer<vtkPolyDataMapper> originalMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      originalMapper->SetInputConnection(originalGlyph3D->GetOutputPort());
      originalMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> originalActor =
        vtkSmartPointer<vtkActor>::New();
      originalActor->SetMapper(originalMapper);
      originalActor->GetProperty()->SetColor(0.8900, 0.8100, 0.3400);

    ////
      vtkSmartPointer<vtkSphereSource> sampleSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sampleSource->SetRadius(radius * .75);

      vtkSmartPointer<vtkGlyph3D> sampleGlyph3D =
        vtkSmartPointer<vtkGlyph3D>::New();
      sampleGlyph3D->SetInputConnection(sample->GetOutputPort());
      sampleGlyph3D->SetSourceConnection(sampleSource->GetOutputPort());
      sampleGlyph3D->ScalingOff();
      sampleGlyph3D->Update();

      vtkSmartPointer<vtkPolyDataMapper> sampleMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      sampleMapper->SetInputConnection(sampleGlyph3D->GetOutputPort());
      sampleMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> sampleActor =
        vtkSmartPointer<vtkActor>::New();
      sampleActor->SetMapper(sampleMapper);
      sampleActor->GetProperty()->SetColor(1.0000, 0.4900, 0.2500);

      // Create graphics stuff
      //
      vtkSmartPointer<vtkRenderer> ren1 =
        vtkSmartPointer<vtkRenderer>::New();
      ren1->SetBackground(.3, .4, .6);

      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->AddRenderer(ren1);
      renWin->SetSize(512,512);

      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      // Add the actors to the renderer, set the background and size
      //
      ren1->AddActor(originalActor);
      ren1->AddActor(sampleActor);

      // Generate an interesting view
      //
      ren1->GetActiveCamera()->SetPosition (1, 0, 0);
      ren1->GetActiveCamera()->SetFocalPoint (0, 1, 0);
      ren1->GetActiveCamera()->SetViewUp (0, 0, 1);
      ren1->ResetCamera();
      ren1->GetActiveCamera()->Dolly(1.0);
      ren1->ResetCameraClippingRange();

      iren->Initialize();
      iren->Start();

      return EXIT_SUCCESS;
    }

    static 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
      {
        vtkSmartPointer<vtkSphereSource> sphere =
          vtkSmartPointer<vtkSphereSource>::New();
        sphere->SetRadius(1.0);
        sphere->SetPhiResolution(21);
        sphere->SetThetaResolution(41);
        sphere->Update();
        polyData = sphere->GetOutput();
      }
      return polyData;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(PolyDataPointSampler)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(PolyDataPointSampler MACOSX_BUNDLE PolyDataPointSampler.cxx )

    target_link_libraries(PolyDataPointSampler ${VTK_LIBRARIES})

### Download and Build PolyDataPointSampler

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

    cd PolyDataPointSampler/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:

    ./PolyDataPointSampler

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