# Silhouette

VTKExamples/Cxx/PolyData/Silhouette

### Code

Silhouette.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyDataSilhouette.h>

    #include <vtkXMLPolyDataReader.h>
    #include <vtkCleanPolyData.h>
    #include <vtkProperty.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkCamera.h>
    #include <vtkActor.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSphereSource.h>

    #include <vtkNamedColors.h>

    int main(int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> polyData;
      if (argc < 2)
      {
        vtkSmartPointer<vtkSphereSource> sphereSource =
          vtkSmartPointer<vtkSphereSource>::New();
        sphereSource->Update();

        polyData = sphereSource->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName(argv[1]);

        vtkSmartPointer<vtkCleanPolyData> clean =
          vtkSmartPointer<vtkCleanPolyData>::New();
        clean->SetInputConnection(reader->GetOutputPort());
        clean->Update();

        polyData = clean->GetOutput();
      }

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      //create mapper and actor for original model
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputData(polyData);
      mapper->ScalarVisibilityOff();

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

      //create renderer and renderWindow
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      renderer->AddActor(actor); //view the original model

      //Compute the silhouette
      vtkSmartPointer<vtkPolyDataSilhouette> silhouette =
        vtkSmartPointer<vtkPolyDataSilhouette>::New();
      silhouette->SetInputData(polyData);
      silhouette->SetCamera(renderer->GetActiveCamera());
      silhouette->SetEnableFeatureAngle(0);

      //create mapper and actor for silouette
      vtkSmartPointer<vtkPolyDataMapper> mapper2 =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper2->SetInputConnection(silhouette->GetOutputPort());

      vtkSmartPointer<vtkActor> actor2 =
        vtkSmartPointer<vtkActor>::New();
      actor2->SetMapper(mapper2);
      actor2->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());
      actor2->GetProperty()->SetLineWidth(5);

      renderer->AddActor(actor2);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());
      renderer->ResetCamera();
      renderer->GetActiveCamera()->Azimuth(30);
      renderer->GetActiveCamera()->Elevation(30);
      renderer->GetActiveCamera()->Dolly(1.5);;
      renderer->ResetCameraClippingRange();

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

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(Silhouette)

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

### Download and Build Silhouette

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

    cd Silhouette/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:

    ./Silhouette

WINDOWS USERS

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