VTK/Examples/Cxx/Interaction/ObserverMemberFunction

#include <vtkPolyDataMapper.h>
#include <vtkObjectFactory.h>
#include <vtkCommand.h>
#include <vtkActor.h>
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyle.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkInteractorStyleTrackballCamera.h>
 
// A class not derived from vtkObjectBase
class MyClass
{
  public:
    void KeypressCallbackFunction(vtkObject* caller,
                    long unsigned int eventId,
                    void* callData )
    {
      std::cout << "Caught event in MyClass" << std::endl;
    }
 
};
 
// A class that is derived from vtkObjectBase
class MyInteractorStyle : public vtkInteractorStyleTrackballCamera
{
  public:
    static MyInteractorStyle* New();
    vtkTypeMacro(MyInteractorStyle, vtkInteractorStyleTrackballCamera);
 
    void KeypressCallbackFunction(vtkObject* caller,
                    long unsigned int eventId,
                    void* callData )
    {
      std::cout << "Caught event in MyInteractorStyle" << std::endl;
    }
 
};
vtkStandardNewMacro(MyInteractorStyle);
 
int main(int, char *[])
{
  // Create a sphere
  vtkSmartPointer<vtkSphereSource> sphereSource =
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  sphereSource->Update();
 
  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(sphereSource->GetOutputPort());
 
  // Create an actor
  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
 
  // 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);
 
  MyClass myClass;
  renderWindowInteractor->AddObserver(vtkCommand::KeyPressEvent, &myClass, &MyClass::KeypressCallbackFunction);
 
  MyInteractorStyle* style = MyInteractorStyle::New();
  renderWindowInteractor->AddObserver(vtkCommand::KeyPressEvent, style, &MyInteractorStyle::KeypressCallbackFunction);
 
  vtkSmartPointer<MyInteractorStyle> style2 =
    vtkSmartPointer<MyInteractorStyle>::New();
  renderWindowInteractor->AddObserver(vtkCommand::KeyPressEvent, style2, &MyInteractorStyle::KeypressCallbackFunction);
 
  renderer->AddActor(actor);
  renderer->SetBackground(1,1,1); // Background color white
  renderWindow->Render();
  renderWindowInteractor->Start();
 
  style->Delete();
 
  return EXIT_SUCCESS;
}