OctreeVisualize

VTKExamples/Cxx/DataStructures/OctreeVisualize


Question

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Code

OctreeVisualize.cxx

#include <vtkActor.h>
#include <vtkCallbackCommand.h>
#include <vtkCommand.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkMath.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkOctreePointLocator.h>
#include <vtkPointSource.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkProperty2D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSliderRepresentation2D.h>
#include <vtkSliderWidget.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkTextProperty.h>
#include <vtkWidgetEvent.h>
#include <vtkWidgetEventTranslator.h>

#include <cmath>

namespace {
class vtkSliderCallback : public vtkCommand {
public:
  static vtkSliderCallback *New()

  {
    return new vtkSliderCallback;
  }
  vtkSliderCallback() : Octree(0), Level(0), PolyData(0), Renderer(0) {}

  virtual void Execute(vtkObject *caller, unsigned long, void *) {
    vtkSliderWidget *sliderWidget = reinterpret_cast<vtkSliderWidget *>(caller);
    this->Level = vtkMath::Round(static_cast<vtkSliderRepresentation *>(
                                     sliderWidget->GetRepresentation())
                                     ->GetValue());

    this->Octree->GenerateRepresentation(this->Level, this->PolyData);
    this->Renderer->Render();
  }

  vtkOctreePointLocator *Octree;
  int Level;
  vtkPolyData *PolyData;
  vtkRenderer *Renderer;
};
} // namespace

int main(int, char *[]) {
  vtkNew<vtkNamedColors> colors;

  // Create a point cloud
  vtkSmartPointer<vtkSphereSource> pointSource =
      vtkSmartPointer<vtkSphereSource>::New();
  pointSource->SetPhiResolution(50);
  pointSource->SetThetaResolution(50);
  vtkSmartPointer<vtkPolyDataMapper> pointsMapper =
      vtkSmartPointer<vtkPolyDataMapper>::New();
  pointsMapper->SetInputConnection(pointSource->GetOutputPort());
  pointSource->Update();
  vtkSmartPointer<vtkActor> pointsActor = vtkSmartPointer<vtkActor>::New();
  pointsActor->SetMapper(pointsMapper);
  pointsActor->GetProperty()->SetInterpolationToFlat();
  pointsActor->GetProperty()->SetRepresentationToPoints();
  pointsActor->GetProperty()->SetColor(colors->GetColor4d("Yellow").GetData());

  // Create the tree
  vtkSmartPointer<vtkOctreePointLocator> octree =
      vtkSmartPointer<vtkOctreePointLocator>::New();
  octree->SetMaximumPointsPerRegion(5);
  octree->SetDataSet(pointSource->GetOutput());
  octree->BuildLocator();

  vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();
  octree->GenerateRepresentation(0, polydata);

  vtkSmartPointer<vtkPolyDataMapper> octreeMapper =
      vtkSmartPointer<vtkPolyDataMapper>::New();
  octreeMapper->SetInputData(polydata);

  vtkSmartPointer<vtkActor> octreeActor = vtkSmartPointer<vtkActor>::New();
  octreeActor->SetMapper(octreeMapper);
  octreeActor->GetProperty()->SetInterpolationToFlat();
  octreeActor->GetProperty()->SetRepresentationToWireframe();
  octreeActor->GetProperty()->SetColor(
      colors->GetColor4d("SpringGreen").GetData());

  // 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(pointsActor);
  renderer->AddActor(octreeActor);
  renderer->SetBackground(colors->GetColor3d("MidnightBlue").GetData());

  // Render an image (lights and cameras are created automatically)
  renderWindow->SetWindowName("OctreeVisualize");
  renderWindow->SetSize(600, 600);
  renderWindow->Render();

  vtkSmartPointer<vtkSliderRepresentation2D> sliderRep =
      vtkSmartPointer<vtkSliderRepresentation2D>::New();
  sliderRep->SetMinimumValue(0);
  sliderRep->SetMaximumValue(octree->GetLevel());
  sliderRep->SetValue(0);
  sliderRep->SetTitleText("Level");
  sliderRep->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay();
  sliderRep->GetPoint1Coordinate()->SetValue(.2, .2);
  sliderRep->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay();
  sliderRep->GetPoint2Coordinate()->SetValue(.8, .2);
  sliderRep->SetSliderLength(0.075);
  sliderRep->SetSliderWidth(0.05);
  sliderRep->SetEndCapLength(0.05);
  sliderRep->GetTitleProperty()->SetColor(
      colors->GetColor3d("Beige").GetData());
  sliderRep->GetCapProperty()->SetColor(
      colors->GetColor3d("MistyRose").GetData());
  sliderRep->GetSliderProperty()->SetColor(
      colors->GetColor3d("LightBlue").GetData());
  sliderRep->GetSelectedProperty()->SetColor(
      colors->GetColor3d("Violet").GetData());

  vtkSmartPointer<vtkSliderWidget> sliderWidget =
      vtkSmartPointer<vtkSliderWidget>::New();
  sliderWidget->SetInteractor(renderWindowInteractor);
  sliderWidget->SetRepresentation(sliderRep);
  sliderWidget->SetAnimationModeToAnimate();
  sliderWidget->EnabledOn();

  vtkSmartPointer<vtkSliderCallback> callback =
      vtkSmartPointer<vtkSliderCallback>::New();
  callback->Octree = octree;
  callback->PolyData = polydata;
  callback->Renderer = renderer;

  sliderWidget->AddObserver(vtkCommand::InteractionEvent, callback);

  renderWindowInteractor->Initialize();
  renderWindow->Render();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(OctreeVisualize)

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

Download and Build OctreeVisualize

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

cd OctreeVisualize/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:

./OctreeVisualize

WINDOWS USERS

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