# ConvexHull

VTKExamples/Cxx/PolyData/ConvexHull

### Code

ConvexHull.cxx

    #include <vtkPoints.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkSmartPointer.h>
    #include <vtkHull.h>

    #include <vtkDataSetMapper.h>
    #include <vtkActor.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>

    #include <vtkNamedColors.h>

    int main(int argc, char *argv[])
    {
      // Parse command line arguments
      if(argc != 2)
      {
        std::cout << "Required arguments: Filename" << std::endl;
        return EXIT_FAILURE;
      }

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

      vtkSmartPointer<vtkXMLPolyDataReader> reader =
        vtkSmartPointer<vtkXMLPolyDataReader>::New();
      reader->SetFileName(argv[1]);

      vtkSmartPointer<vtkHull> hullFilter =
        vtkSmartPointer<vtkHull>::New();
      hullFilter->SetInputConnection(reader->GetOutputPort());
      hullFilter->AddCubeFacePlanes ();
      hullFilter->AddRecursiveSpherePlanes(5);

      vtkSmartPointer<vtkDataSetMapper> originalMapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      originalMapper->SetInputConnection(reader->GetOutputPort());
      originalMapper->ScalarVisibilityOff();

      // Create an actor for the surface
      vtkSmartPointer<vtkActor> originalActor =
        vtkSmartPointer<vtkActor>::New();
      originalActor->SetMapper(originalMapper);
      originalActor->GetProperty()->SetDiffuseColor(
        namedColors->GetColor3d("Banana").GetData());

      vtkSmartPointer<vtkDataSetMapper> mapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      mapper->SetInputConnection(hullFilter->GetOutputPort());
      mapper->ScalarVisibilityOff();

      // Create an actor for the surface
      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetDiffuseColor(
        namedColors->GetColor3d("Tomato").GetData());
      actor->GetProperty()->SetEdgeColor(
        namedColors->GetColor3d("IvoryBlack").GetData());
      actor->GetProperty()->SetOpacity(.5);
      actor->GetProperty()->EdgeVisibilityOff();

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(renderWindow);

      renderer->AddActor(originalActor);
      renderer->AddActor(actor);
      renderer->SetBackground(namedColors->GetColor3d("SlateGray").GetData());

      renderWindow->Render();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ConvexHull)

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

    add_executable(ConvexHull MACOSX_BUNDLE ConvexHull.cxx )

    target_link_libraries(ConvexHull ${VTK_LIBRARIES})

### Download and Build ConvexHull

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

    cd ConvexHull/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:

    ./ConvexHull

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.