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DataStructureComparison

vtk-examples/Cxx/DataStructures/DataStructureComparison


Description

Prior to August 20, 2010, the vtkModifiedBSPTree.cxx did not produce a proper data representation. To operate properly, update your vtk source tree.

Use the 'n' key (for 'N'ext) and the 'p' key (for 'P'revious) to navigate the levels of the trees.

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

DataStructureComparison.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkNew.h>
#include <vtkPointSource.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkXMLPolyDataReader.h>

#include <vtkKdTreePointLocator.h>
#include <vtkModifiedBSPTree.h>
#include <vtkOBBTree.h>
#include <vtkOctreePointLocator.h>

#include <vector>

namespace {
class KeyPressInteractorStyle : public vtkInteractorStyleTrackballCamera
{
public:
  static KeyPressInteractorStyle* New();
  vtkSmartPointer<vtkPolyData> data;
  std::vector<vtkRenderer*> renderers;
  std::vector<vtkSmartPointer<vtkLocator>> trees;
  std::vector<vtkSmartPointer<vtkPolyDataMapper>> mappers;
  std::vector<vtkSmartPointer<vtkActor>> actors;

  vtkSmartPointer<vtkPolyDataMapper> meshMapper;
  vtkSmartPointer<vtkActor> meshActor;

  void Initialize()
  {
    this->meshMapper->SetInputData(this->data);
    for (unsigned int i = 0; i < 4; i++)
    {
      vtkSmartPointer<vtkPolyDataMapper> mapper =
          vtkSmartPointer<vtkPolyDataMapper>::New();
      this->mappers.push_back(mapper);
      vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetRepresentationToWireframe();
      this->actors.push_back(actor);
      this->renderers[i]->AddActor(actor);

      this->renderers[i]->AddActor(meshActor);
    }
    this->Level = 1;
    std::cout << "Level = " << this->Level << std::endl;
    this->ReDraw();
  }

  KeyPressInteractorStyle()
  {
    this->Level = 1;

    vtkSmartPointer<vtkLocator> tree0 =
        vtkSmartPointer<vtkKdTreePointLocator>::New();
    this->trees.push_back(tree0);
    vtkSmartPointer<vtkLocator> tree1 = vtkSmartPointer<vtkOBBTree>::New();
    this->trees.push_back(tree1);
    vtkSmartPointer<vtkLocator> tree2 =
        vtkSmartPointer<vtkOctreePointLocator>::New();
    this->trees.push_back(tree2);
    vtkSmartPointer<vtkLocator> tree3 =
        vtkSmartPointer<vtkModifiedBSPTree>::New();
    this->trees.push_back(tree3);

    this->meshMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    this->meshActor = vtkSmartPointer<vtkActor>::New();
    this->meshActor->SetMapper(this->meshMapper);
  }

  virtual void OnChar()
  {
    char ch = this->Interactor->GetKeyCode();

    switch (ch)
    {
    case 'n':
      this->Level++;
      break;
    case 'p':
      if (this->Level > 1)
      {
        this->Level--;
      }
      break;
    default:
      std::cout << "An unhandled key was pressed." << std::endl;
      break;
    }

    this->ReDraw();

    // Forward events.
    if (ch != 'p') // Don't forward the "pick" command.
    {
      vtkInteractorStyleTrackballCamera::OnChar();
    }
  }

  void ReDraw()
  {

    std::cout << "Level " << this->Level << std::endl;
    for (unsigned i = 0; i < 4; i++)
    {

      vtkSmartPointer<vtkLocator> tree = this->trees[i];
      // vtkRenderer* renderer = this->renderers[i];

      tree->SetDataSet(data);
      tree->BuildLocator();

      vtkSmartPointer<vtkPolyData> polydata =
          vtkSmartPointer<vtkPolyData>::New();
      std::cout << "Tree " << i << " has " << tree->GetLevel() << " levels."
                << std::endl;

      if (this->Level > tree->GetLevel())
      {
        tree->GenerateRepresentation(tree->GetLevel(), polydata);
      }
      else
      {
        tree->GenerateRepresentation(this->Level, polydata);
      }

      this->mappers[i]->SetInputData(polydata);
    }

    this->Interactor->GetRenderWindow()->Render();
  }

private:
  int Level;
};

vtkStandardNewMacro(KeyPressInteractorStyle);

} // namespace

int main(int argc, char* argv[])
{
  vtkNew<vtkPolyData> originalMesh;

  if (argc > 1) // If a file name is specified, open and use the file.
  {
    vtkNew<vtkXMLPolyDataReader> reader;
    reader->SetFileName(argv[1]);
    reader->Update();
    originalMesh->ShallowCopy(reader->GetOutput());
  }
  else // If a file name is not specified, create a random cloud of points.
  {
    vtkNew<vtkPointSource> sphereSource;
    sphereSource->SetNumberOfPoints(1000);

    sphereSource->Update();
    originalMesh->ShallowCopy(sphereSource->GetOutput());
  }

  double numberOfViewports = 4.;

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetSize(200 * numberOfViewports, 200); //(width, height)
  renderWindow->SetWindowName("DataStructureComparison");

  vtkNew<KeyPressInteractorStyle> style;
  style->data = originalMesh;

  vtkNew<vtkCamera> camera;

  for (unsigned int i = 0; i < 4; i++)
  {
    vtkNew<vtkRenderer> renderer;
    renderWindow->AddRenderer(renderer);
    style->renderers.push_back(renderer);
    renderer->SetViewport(static_cast<double>(i) / numberOfViewports, 0,
                          static_cast<double>(i + 1) / numberOfViewports, 1);
    renderer->SetBackground(0.2, 0.3, 0.4);
    renderer->SetActiveCamera(camera);
  }

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);
  renderWindowInteractor->SetInteractorStyle(style);
  style->Initialize();
  style->renderers[0]->ResetCamera();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(DataStructureComparison)

find_package(VTK COMPONENTS 
  CommonCore
  CommonDataModel
  FiltersFlowPaths
  FiltersGeneral
  FiltersSources
  IOXML
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "DataStructureComparison: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(DataStructureComparison MACOSX_BUNDLE DataStructureComparison.cxx )
  target_link_libraries(DataStructureComparison PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS DataStructureComparison
  MODULES ${VTK_LIBRARIES}
)

Download and Build DataStructureComparison

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

cd DataStructureComparison/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:

./DataStructureComparison

WINDOWS USERS

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