# GeometricObjectsDemo

VTKExamples/Cxx/GeometricObjects/GeometricObjectsDemo

### Code

GeometricObjectsDemo.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkTextMapper.h>
    #include <vtkActor.h>
    #include <vtkActor2D.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>

    #include <vtkArrowSource.h>
    #include <vtkConeSource.h>
    #include <vtkCubeSource.h>
    #include <vtkCylinderSource.h>
    #include <vtkDiskSource.h>
    #include <vtkLineSource.h>
    #include <vtkRegularPolygonSource.h>
    #include <vtkSphereSource.h>

    #include <vector>

    int main(int, char *[])
    {
      // Create container to hold the 3D object generators (sources)
      std::vector<vtkSmartPointer<vtkPolyDataAlgorithm> > geometricObjectSources;

      // Populate the container with the various object sources to be demonstrated
      geometricObjectSources.push_back( vtkSmartPointer<vtkArrowSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkConeSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkCubeSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkCylinderSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkDiskSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkLineSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkRegularPolygonSource>::New() );
      geometricObjectSources.push_back( vtkSmartPointer<vtkSphereSource>::New() );

      // Create containers for the remaining nodes of each pipeline
      std::vector<vtkSmartPointer<vtkRenderer> > renderers;
      std::vector<vtkSmartPointer<vtkPolyDataMapper> > mappers;
      std::vector<vtkSmartPointer<vtkActor> > actors;
      std::vector<vtkSmartPointer<vtkTextMapper> > textmappers;
      std::vector<vtkSmartPointer<vtkActor2D> > textactors;

      // Create a mapper and actor for each object and the corresponding text label
      for( unsigned int i = 0; i < geometricObjectSources.size(); i++ )
      {
        geometricObjectSources[i]->Update();

        mappers.push_back( vtkSmartPointer<vtkPolyDataMapper>::New() );
        mappers[i]->SetInputConnection( geometricObjectSources[i]->GetOutputPort() );

        actors.push_back( vtkSmartPointer<vtkActor>::New() );
        actors[i]->SetMapper( mappers[i] );

        textmappers.push_back( vtkSmartPointer<vtkTextMapper>::New() );
        textmappers[i]->SetInput( geometricObjectSources[i]->GetClassName() ); // set text label to the name of the object source

        textactors.push_back( vtkSmartPointer<vtkActor2D>::New() );
        textactors[i]->SetMapper( textmappers[i] );
        textactors[i]->SetPosition( 10, 10); // Note: the position of an Actor2D is specified in display coordinates
      }

      // Define size of the grid that will hold the objects
      int gridCols = 3;
      int gridRows = 3;
      // Define side length (in pixels) of each renderer square
      int rendererSize = 200;

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(rendererSize*gridCols, rendererSize*gridRows);

      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();

      // Set up a grid of viewports for each renderer
      for( double row = 0; row < gridRows; row++ )
      {
        for( double col = 0; col < gridCols; col++ )
        {
          double index = row*gridCols + col;

          // Create a renderer for this grid cell
          vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
          renderer->SetBackground(.1, .2, .3);

          // Set the renderer's viewport dimensions (xmin, ymin, xmax, ymax) within the render window.
          // Note that for the Y values, we need to subtract the row index from gridRows
          // because the viewport Y axis points upwards, but we want to draw the grid from top to down
          double viewport[4] = {
            ((col    )              * rendererSize) / (gridCols * rendererSize),
            ((gridRows - (row + 1)) * rendererSize) / (gridRows * rendererSize),
            ((col + 1)              * rendererSize) / (gridCols * rendererSize),
            ((gridRows - (row    )) * rendererSize) / (gridRows * rendererSize) };
          renderer->SetViewport(viewport);

          // Add the corresponding actor and label for this grid cell, if they exist
          if( index < geometricObjectSources.size() )
          {
            renderer->AddActor(actors[index]);
            renderer->AddActor(textactors[index]);
          }

          renderWindow->AddRenderer(renderer);
        }
      }

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

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(GeometricObjectsDemo)

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

    add_executable(GeometricObjectsDemo MACOSX_BUNDLE GeometricObjectsDemo.cxx )

    target_link_libraries(GeometricObjectsDemo ${VTK_LIBRARIES})

### Download and Build GeometricObjectsDemo

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

    cd GeometricObjectsDemo/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:

    ./GeometricObjectsDemo

WINDOWS USERS

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