HighlightPickedActor

VTKExamples/Cxx/Picking/HighlightPickedActor


Description

Click on a sphere to highlight it. The picked sphere color changes to red, and its EdgeVisibity is On. The example subclasses vtkInteractorStyleTrackballCamera with a local class called MouseInteractorHighLightActor. The new interactor overrides the OnLeftButtonDown of vtkInteractorStyleTrackballCamera.

Code

HighlightPickedActor.cxx

#include <vtkActor.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkMath.h>
#include <vtkNamedColors.h>
#include <vtkObjectFactory.h>
#include <vtkPolyDataMapper.h>
#include <vtkPropPicker.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>

namespace
{
// Handle mouse events
class MouseInteractorHighLightActor : public vtkInteractorStyleTrackballCamera
{
public:
  static MouseInteractorHighLightActor* New();
  vtkTypeMacro(MouseInteractorHighLightActor,
               vtkInteractorStyleTrackballCamera);

  MouseInteractorHighLightActor()
  {
    LastPickedActor = NULL;
    LastPickedProperty = vtkProperty::New();
  }
  virtual ~MouseInteractorHighLightActor()
  {
    LastPickedProperty->Delete();
  }
  virtual void OnLeftButtonDown() override
  {
    auto colors =   vtkSmartPointer<vtkNamedColors>::New();

    int* clickPos = this->GetInteractor()->GetEventPosition();

    // Pick from this location.
    auto picker =
        vtkSmartPointer<vtkPropPicker>::New();
    picker->Pick(clickPos[0], clickPos[1], 0, this->GetDefaultRenderer());

    // If we picked something before, reset its property
    if (this->LastPickedActor)
    {
      this->LastPickedActor->GetProperty()->DeepCopy(this->LastPickedProperty);
    }
    this->LastPickedActor = picker->GetActor();
    if (this->LastPickedActor)
    {
      // Save the property of the picked actor so that we can
      // restore it next time
      this->LastPickedProperty->DeepCopy(this->LastPickedActor->GetProperty());
      // Highlight the picked actor by changing its properties
      this->LastPickedActor->GetProperty()->SetColor(
          colors->GetColor3d("Red").GetData());
      this->LastPickedActor->GetProperty()->SetDiffuse(1.0);
      this->LastPickedActor->GetProperty()->SetSpecular(0.0);
      this->LastPickedActor->GetProperty()->EdgeVisibilityOn();
    }

    // Forward events
    vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
  }

private:
  vtkActor* LastPickedActor;
  vtkProperty* LastPickedProperty;
};
}

vtkStandardNewMacro(MouseInteractorHighLightActor);

// Execute application.
int main(int argc, char* argv[])
{
  auto colors =
      vtkSmartPointer<vtkNamedColors>::New();

  colors->SetColor("Bkg", 0.3, 0.4, 0.5);

  int numberOfSpheres = 10;
  if (argc > 1)
  {
    numberOfSpheres = atoi(argv[1]);
  }
  // A renderer and render window
  auto renderer =
      vtkSmartPointer<vtkRenderer>::New();
  auto renderWindow =
      vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetSize(640, 480);
  renderWindow->AddRenderer(renderer);

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

  // Set the custom type to use for interaction.
  auto style =
      vtkSmartPointer<MouseInteractorHighLightActor>::New();
  style->SetDefaultRenderer(renderer);

  renderWindowInteractor->SetInteractorStyle(style);

  for (int i = 0; i < numberOfSpheres; ++i)
  {
    auto source =
        vtkSmartPointer<vtkSphereSource>::New();
    double x, y, z, radius;
    x = vtkMath::Random(-5, 5);
    y = vtkMath::Random(-5, 5);
    z = vtkMath::Random(-5, 5);
    radius = vtkMath::Random(0.5, 1.0);
    source->SetRadius(radius);
    source->SetCenter(x, y, z);
    source->SetPhiResolution(11);
    source->SetThetaResolution(21);
    auto mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(source->GetOutputPort());
    auto actor =
        vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);
    double r, g, b;
    r = vtkMath::Random(0.4, 1.0);
    g = vtkMath::Random(0.4, 1.0);
    b = vtkMath::Random(0.4, 1.0);
    actor->GetProperty()->SetDiffuseColor(r, g, b);
    actor->GetProperty()->SetDiffuse(0.8);
    actor->GetProperty()->SetSpecular(0.5);
    actor->GetProperty()->SetSpecularColor(
        colors->GetColor3d("White").GetData());
    actor->GetProperty()->SetSpecularPower(30.0);
    renderer->AddActor(actor);
  }

  renderer->SetBackground(colors->GetColor3d("Bkg").GetData());

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

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(HighlightPickedActor)

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

Download and Build HighlightPickedActor

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

cd HighlightPickedActor/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:

./HighlightPickedActor

WINDOWS USERS

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