# TrackballCamera

VTKExamples/Cxx/Interaction/TrackballCamera

### Description

This example demonstrates the trackball camera mode. When the mouse is clicked and dragged from anywhere in the window, the camera is modified.

Contrast this with TrackballActor.

### Code

TrackballCamera.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkPolyData.h>
    #include <vtkSphereSource.h>
    #include <vtkConeSource.h>
    #include <vtkInteractorStyleTrackballCamera.h>

    int main (int, char *[])
    {
      // Create a sphere
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->SetCenter(1.0, 0.0, 0.0);
      sphereSource->Update();

      // Create a mapper and actor
      vtkSmartPointer<vtkPolyDataMapper> sphereMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      sphereMapper->SetInputConnection(sphereSource->GetOutputPort());

      vtkSmartPointer<vtkActor> sphereActor =
        vtkSmartPointer<vtkActor>::New();
      sphereActor->SetMapper(sphereMapper);

      // Create a cone
      vtkSmartPointer<vtkConeSource> coneSource =
        vtkSmartPointer<vtkConeSource>::New();

      // Create a mapper and actor
      vtkSmartPointer<vtkPolyDataMapper> coneMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      coneMapper->SetInputConnection(coneSource->GetOutputPort());

      vtkSmartPointer<vtkActor> coneActor =
        vtkSmartPointer<vtkActor>::New();
      coneActor->SetMapper(coneMapper);

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

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

      // Add the actors to the scene
      renderer->AddActor(sphereActor);
      renderer->AddActor(coneActor);
      renderer->SetBackground(.1,.2,.3); // Background color dark blue

      // Render an image (lights and cameras are created automatically)
      renderWindow->SetWindowName("Trackball Camera");
      renderWindow->Render();

      vtkSmartPointer<vtkInteractorStyleTrackballCamera> style =
        vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New(); //like paraview

      renderWindowInteractor->SetInteractorStyle( style );

      // Begin mouse interaction
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(TrackballCamera)

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

    add_executable(TrackballCamera MACOSX_BUNDLE TrackballCamera.cxx )

    target_link_libraries(TrackballCamera ${VTK_LIBRARIES})

### Download and Build TrackballCamera

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

    cd TrackballCamera/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:

    ./TrackballCamera

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.