CameraModifiedEvent

VTKExamples/Cxx/Utilities/CameraModifiedEvent


Question

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Code

CameraModifiedEvent.cxx

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

static void CameraModifiedCallback(vtkObject* caller,
                                   long unsigned int vtkNotUsed(eventId),
                                   void* vtkNotUsed(clientData),
                                   void* vtkNotUsed(callData) )
{
  std::cout << caller->GetClassName() << " modified" << std::endl;

  vtkCamera* camera = static_cast<vtkCamera*>(caller);
  // print the interesting stuff
  std::cout << "\tPosition: "
            << camera->GetPosition()[0] << ", "
            << camera->GetPosition()[1] << ", "
            << camera->GetPosition()[2] << std::endl;
  std::cout << "\tFocal point: "
            << camera->GetFocalPoint()[0] << ", "
            << camera->GetFocalPoint()[1] << ", "
            << camera->GetFocalPoint()[2] << std::endl;
}

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

  // Create a renderer, render window, and interactor
  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actor to the scene
  renderer->AddActor(actor);
  renderer->SetBackground(.1, .3, .5);

  vtkSmartPointer<vtkCallbackCommand> modifiedCallback =
    vtkSmartPointer<vtkCallbackCommand>::New();
  modifiedCallback->SetCallback (CameraModifiedCallback);

  renderer->ResetCamera();
  renderer->GetActiveCamera()->AddObserver(vtkCommand::ModifiedEvent,modifiedCallback);

  // Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(CameraModifiedEvent)

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

Download and Build CameraModifiedEvent

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

cd CameraModifiedEvent/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:

./CameraModifiedEvent

WINDOWS USERS

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