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# HideActor

VTKEx/Cxx/Visualization/HideActor

### Description

Display two spheres, then hide one, then hide both.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

### Code

HideActor.cxx

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

    int main (int, char *[])
    {
      // Sphere 1
      vtkSmartPointer<vtkSphereSource> sphereSource1 =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource1->SetCenter(0.0, 0.0, 0.0);
      sphereSource1->SetRadius(4.0);
      sphereSource1->Update();

      vtkSmartPointer<vtkPolyDataMapper> mapper1 =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper1->SetInputConnection(sphereSource1->GetOutputPort());

      vtkSmartPointer<vtkActor> actor1 =
        vtkSmartPointer<vtkActor>::New();
      actor1->SetMapper(mapper1);

      // Sphere 2
      vtkSmartPointer<vtkSphereSource> sphereSource2 =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource2->SetCenter(10.0, 0.0, 0.0);
      sphereSource2->SetRadius(3.0);
      sphereSource2->Update();

      // Create a mapper
      vtkSmartPointer<vtkPolyDataMapper> mapper2 =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper2->SetInputConnection(sphereSource2->GetOutputPort());

      // Create an actor
      vtkSmartPointer<vtkActor> actor2 =
        vtkSmartPointer<vtkActor>::New();
      actor2->SetMapper(mapper2);

      // 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(actor1);
      renderer->AddActor(actor2);
      renderer->SetBackground(1,1,1); // Background color white

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

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

      renderWindowInteractor->SetInteractorStyle( style );

      renderWindowInteractor->Start();

      // Set the background to red so we know we are done with the original two sphere display
      renderer->SetBackground(1,0,0);

      // Hide one actor at a time
      vtkPropCollection* props = renderer->GetViewProps(); //iterate through and set each visibility to 0
      props->InitTraversal();
      for(int i = 0; i < props->GetNumberOfItems(); i++)
      {
        props->GetNextProp()->VisibilityOff();

        renderer->ResetCamera();
        renderWindow->Render();

        renderWindowInteractor->Start();
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(HideActor)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping HideActor: ${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(HideActor MACOSX_BUNDLE HideActor.cxx )
      target_link_libraries(HideActor PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(HideActor MACOSX_BUNDLE HideActor.cxx )
      target_link_libraries(HideActor PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS HideActor
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build HideActor

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

    cd HideActor/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:

    ./HideActor

WINDOWS USERS

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