# ShareCamera

VTKExamples/Cxx/Utilities/ShareCamera

### Code

ShareCamera.cxx

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

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

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

      renderWindowInteractor->SetRenderWindow(renderWindow);

      // Define viewport ranges
      double xmins[4] = {0,.5,0,.5};
      double xmaxs[4] = {0.5,1,0.5,1};
      double ymins[4] = {0,0,.5,.5};
      double ymaxs[4]= {0.5,0.5,1,1};

      vtkCamera* camera = nullptr;

      for(unsigned i = 0; i < 4; i++)
      {
        vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();

        renderWindow->AddRenderer(renderer);

        if(i == 0)
        {
          camera = renderer->GetActiveCamera();
        }
        else
        {
          renderer->SetActiveCamera(camera);
        }
        renderer->SetViewport(xmins[i],ymins[i],xmaxs[i],ymaxs[i]);

        // Create a sphere
        vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New();
        sphereSource->SetCenter(0.0, 0.0, 0.0);
        sphereSource->SetRadius(5);
        sphereSource->Update();

        // Create a mapper and actor
        vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
        mapper->SetInputConnection(sphereSource->GetOutputPort());
        vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
        actor->SetMapper(mapper);
        renderer->AddActor(actor);
        renderer->ResetCamera();

        renderWindow->Render();
        renderWindow->SetWindowName("Multiple ViewPorts");

      }

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ShareCamera)

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

### Download and Build ShareCamera

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

    cd ShareCamera/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:

    ./ShareCamera

WINDOWS USERS

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