VisualizeKDTree

VTKExamples/Cxx/DataStructures/VisualizeKDTree


Description

This demo shows every level of a kdTree.

Code

VisualizeKDTree.cxx

#include <vtkVersion.h>
#include <vtkPointSource.h>
#include <vtkKdTreePointLocator.h>
#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkSliderWidget.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>
#include <vtkCommand.h>
#include <vtkWidgetEvent.h>
#include <vtkCallbackCommand.h>
#include <vtkWidgetEventTranslator.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkSliderWidget.h>
#include <vtkSliderRepresentation2D.h>
#include <vtkProperty.h>
#include <vtkMath.h>

class vtkSliderCallback : public vtkCommand
{
public:
  static vtkSliderCallback *New()
  {
    return new vtkSliderCallback;
  }
  vtkSliderCallback():KdTree(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->KdTree->GenerateRepresentation(this->Level, this->PolyData);
    this->Renderer->Render();
  }

  vtkKdTreePointLocator* KdTree;
  int Level;
  vtkPolyData* PolyData;
  vtkRenderer* Renderer;
};

int main (int, char *[])
{
  // Create a point cloud
  vtkSmartPointer<vtkPointSource> pointSource =
    vtkSmartPointer<vtkPointSource>::New();
  pointSource->SetRadius(4);
  pointSource->SetNumberOfPoints(1000);
  pointSource->Update();

  vtkSmartPointer<vtkPolyDataMapper> pointsMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  pointsMapper->SetInputConnection(pointSource->GetOutputPort());

  vtkSmartPointer<vtkActor> pointsActor =
    vtkSmartPointer<vtkActor>::New();
  pointsActor->SetMapper(pointsMapper);
  pointsActor->GetProperty()->SetInterpolationToFlat();

  int maxLevel = 20;
  // Create the tree
  vtkSmartPointer<vtkKdTreePointLocator> kdTree =
    vtkSmartPointer<vtkKdTreePointLocator>::New();
  kdTree->SetDataSet(pointSource->GetOutput());
  kdTree->AutomaticOff();
  kdTree->SetMaxLevel(maxLevel);
  kdTree->BuildLocator();

  // Initialize the representation
  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  kdTree->GenerateRepresentation(0, polydata);

  vtkSmartPointer<vtkPolyDataMapper> octreeMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
#if VTK_MAJOR_VERSION <= 5
  octreeMapper->SetInputConnection(polydata->GetProducerPort());
#else
  octreeMapper->SetInputData(polydata);
#endif

  vtkSmartPointer<vtkActor> octreeActor =
    vtkSmartPointer<vtkActor>::New();
  octreeActor->SetMapper(octreeMapper);
  octreeActor->GetProperty()->SetInterpolationToFlat();
  octreeActor->GetProperty()->SetRepresentationToWireframe();

  // 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);

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

  vtkSmartPointer<vtkSliderRepresentation2D> sliderRep =
    vtkSmartPointer<vtkSliderRepresentation2D>::New();
  sliderRep->SetMinimumValue(0);
  sliderRep->SetMaximumValue(kdTree->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);

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

  vtkSmartPointer<vtkSliderCallback> callback =
    vtkSmartPointer<vtkSliderCallback>::New();
  callback->KdTree = kdTree;
  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 2.8)

PROJECT(VisualizeKDTree)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(VisualizeKDTree MACOSX_BUNDLE VisualizeKDTree.cxx )

target_link_libraries(VisualizeKDTree ${VTK_LIBRARIES})

Download and Build VisualizeKDTree

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

cd VisualizeKDTree/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:

./VisualizeKDTree

WINDOWS USERS

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