# Planes

VTKExamples/Cxx/GeometricObjects/Planes

### Code

Planes.cxx

    #include <vtkActor.h>
    #include <vtkActor2D.h>
    #include <vtkCamera.h>
    #include <vtkHull.h>
    #include <vtkNamedColors.h>
    #include <vtkPlanes.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSmartPointer.h>
    #include <vtkSphereSource.h>
    #include <vtkTextMapper.h>
    #include <vtkTextProperty.h>

    #include <string>
    #include <vector>

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

      // These are the two methods we will use.
      std::vector<std::string> titles{"Using frustum planes", "Using bounds"};
      std::vector<vtkSmartPointer<vtkPlanes>> planes;
      for (auto i = 0; i < titles.size(); ++i)
      {
        planes.push_back(vtkSmartPointer<vtkPlanes>::New());
      }

      // Using frustum planes.
      vtkSmartPointer<vtkCamera> camera =
        vtkSmartPointer<vtkCamera>::New();
      double planesArray[24];
      camera->GetFrustumPlanes(1, planesArray);
      planes[0]->SetFrustumPlanes(planesArray);

      // Using bounds.
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();
      double bounds[6];
      sphereSource->GetOutput()->GetBounds(bounds);
      planes[1]->SetBounds(bounds);

      // At this point we have the planes created by both of the methods above.
      // You can do whatever you want with them.

      // For visualisation we will produce an n-sided convex hull
      // and visualise it.

      // Create a common text property.
      vtkSmartPointer<vtkTextProperty> textProperty =
        vtkSmartPointer<vtkTextProperty>::New();
      textProperty->SetFontSize(16);
      textProperty->SetJustificationToCentered();

      // Create the render window and interactor.
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->SetWindowName("Planes");
      vtkSmartPointer<vtkRenderWindowInteractor> iRen =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iRen->SetRenderWindow(renWin);

      std::vector<vtkSmartPointer<vtkHull>> hulls;
      std::vector<vtkSmartPointer<vtkPolyData>> pds;
      std::vector<vtkSmartPointer<vtkPolyDataMapper>> mappers;
      std::vector<vtkSmartPointer<vtkActor>> actors;
      std::vector<vtkSmartPointer<vtkTextMapper>> textMappers;
      std::vector<vtkSmartPointer<vtkActor2D>> textActors;
      std::vector<vtkSmartPointer<vtkRenderer>> renderers;

      for (auto i = 0; i < titles.size(); ++i)
      {
        hulls.push_back(vtkSmartPointer<vtkHull>::New());
        hulls[i]->SetPlanes(planes[i]);

        pds.push_back(vtkSmartPointer<vtkPolyData>::New());

        // To generate the convex hull we supply a vtkPolyData object and a bounding
        // box.
        // We define the bounding box to be where we expect the resulting polyhedron
        // to lie.
        // Make it a generous fit as it is only used to create the initial
        // polygons that are eventually clipped.
        hulls[i]->GenerateHull(pds[i], -200, 200, -200, 200, -200, 200);

        mappers.push_back(vtkSmartPointer<vtkPolyDataMapper>::New());
        mappers[i]->SetInputData(pds[i]);

        actors.push_back(vtkSmartPointer<vtkActor>::New());
        actors[i]->SetMapper(mappers[i]);
        actors[i]->GetProperty()->SetColor(
          colors->GetColor3d("Moccasin").GetData());
        actors[i]->GetProperty()->SetSpecular(0.8);
        actors[i]->GetProperty()->SetSpecularPower(30);

        textMappers.push_back(vtkSmartPointer<vtkTextMapper>::New());
        textMappers[i]->SetInput(titles[i].c_str());
        textMappers[i]->SetTextProperty(textProperty);

        textActors.push_back(vtkSmartPointer<vtkActor2D>::New());
        textActors[i]->SetMapper(textMappers[i]);
        textActors[i]->SetPosition(120, 16);

        renderers.push_back(vtkSmartPointer<vtkRenderer>::New());
        renderers[i]->AddActor(actors[i]);
        renderers[i]->AddViewProp(textActors[i]);

        renWin->AddRenderer(renderers[i]);
      }

      // Setup the viewports
      auto xGridDimensions = 2;
      auto yGridDimensions = 1;
      auto rendererSize = 300;
      renWin->SetSize(rendererSize * xGridDimensions,
                      rendererSize * yGridDimensions);
      for (auto row = 0; row < yGridDimensions; ++row)
      {
        for (auto col = 0; col < xGridDimensions; ++col)
        {
          auto index = row * xGridDimensions + col;

          // (xmin, ymin, xmax, ymax)
          double viewport[4] = {
            static_cast<double>(col) / xGridDimensions,
            static_cast<double>(yGridDimensions - (row + 1)) / yGridDimensions,
            static_cast<double>(col + 1) / xGridDimensions,
            static_cast<double>(yGridDimensions - row) / yGridDimensions};
          if (index > (actors.size() - 1))
          {
            // Add a renderer even if there is no actor.
            // This makes the render window background all the same color.
            vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
            ren->SetBackground(colors->GetColor3d("DarkSlateGray").GetData());
            ren->SetViewport(viewport);
            renWin->AddRenderer(ren);
            continue;
          }

          renderers[index]->SetViewport(viewport);
          renderers[index]->SetBackground(
            colors->GetColor3d("DarkSlateGray").GetData());
          renderers[index]->ResetCamera();
          renderers[index]->GetActiveCamera()->Azimuth(30);
          renderers[index]->GetActiveCamera()->Elevation(-30);
          renderers[index]->ResetCameraClippingRange();
        }
      }

      iRen->Initialize();
      renWin->Render();
      iRen->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Planes)

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

    add_executable(Planes MACOSX_BUNDLE Planes.cxx )

    target_link_libraries(Planes ${VTK_LIBRARIES})

### Download and Build Planes

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

    cd Planes/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:

    ./Planes

WINDOWS USERS

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