# ShepardInterpolation

VTKExamples/Cxx/Visualization/ShepardInterpolation

### Code

ShepardInterpolation.cxx

    #include <vtkSmartPointer.h>
    #include <vtkShepardMethod.h>
    #include <vtkContourFilter.h>
    #include <vtkProbeFilter.h>

    #include <vtkNamedColors.h>
    #include <vtkImageData.h>
    #include <vtkPointData.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 <vtkActor.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkCamera.h>

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

    int main (int argc, char *argv[])
    {
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

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

      vtkSmartPointer<vtkShepardMethod> interpolator =
        vtkSmartPointer<vtkShepardMethod>::New();
      interpolator->SetInputData(polyData);
      interpolator->SetModelBounds(polyData->GetBounds());
      interpolator->SetSampleDimensions(200, 200, 200);
      interpolator->SetNullValue(-10000);
      interpolator->Update();
      std::cout << "Scalar Range: "
                << interpolator->GetOutput()->GetScalarRange()[0] << ", "
                << interpolator->GetOutput()->GetScalarRange()[1]
                << std::endl;

      vtkSmartPointer<vtkProbeFilter> probe =
        vtkSmartPointer<vtkProbeFilter>::New();
      probe->SetInputData(0, polyData);
      probe->SetInputConnection(1, interpolator->GetOutputPort());

      vtkSmartPointer<vtkContourFilter> contour =
        vtkSmartPointer<vtkContourFilter>::New();
      contour->SetInputConnection(probe->GetOutputPort());
      contour->SetValue(0, 0.0);

      vtkSmartPointer<vtkContourFilter> dataContour =
        vtkSmartPointer<vtkContourFilter>::New();
      dataContour->SetInputData(polyData);
      dataContour->SetValue(0, 0.0);

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(contour->GetOutputPort());
      mapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
      actor->GetProperty()->SetLineWidth(4.0);

      vtkSmartPointer<vtkPolyDataMapper> dataMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      dataMapper->SetInputConnection(dataContour->GetOutputPort());
      dataMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> dataActor =
        vtkSmartPointer<vtkActor>::New();
      dataActor->SetMapper(dataMapper);
      dataActor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());
      dataActor->GetProperty()->SetLineWidth(4.0);
      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(dataActor);
      renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

      renderer->ResetCamera();
      renderer->GetActiveCamera()->Azimuth(120);
      renderer->GetActiveCamera()->Elevation(30);
      renderer->GetActiveCamera()->Dolly(1.5);
      renderer->ResetCameraClippingRange();

      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;
    }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ShepardInterpolation)

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

    add_executable(ShepardInterpolation MACOSX_BUNDLE ShepardInterpolation.cxx )

    target_link_libraries(ShepardInterpolation ${VTK_LIBRARIES})

### Download and Build ShepardInterpolation

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

    cd ShepardInterpolation/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:

    ./ShepardInterpolation

WINDOWS USERS

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