# CompareExtractSurface

VTKExamples/Cxx/Points/CompareExtractSurface

### Description

This example compares three surface reconstruction algorithms:

1. ExtractSurface
2. PoissonReconstruction
3. Powercrust

We usually try to keep examples short, but this example teaches several concepts.

1. Compare multiple algorithms
2. Time multiple algorithms
3. Reuse code from other examples
4. Use multiple remote modules
5. Generate figures for papers

Warning

This example runs longer than most. Be patient.

Info

See PoissonReconstruction Remote Module to configure.

Info

See Powercrust Remote Module to configure.

### Code

CompareExtractSurface.cxx

    #include <vtkSmartPointer.h>

    #include <vtkBYUReader.h>
    #include <vtkPLYReader.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkOBJReader.h>
    #include <vtkSTLReader.h>
    #include <vtkPointSource.h>

    #include <vtkPCANormalEstimation.h>
    #include <vtkSignedDistance.h>
    #include <vtkExtractSurface.h>
    #include <vtkExtractSurface.h>
    #include <vtkPoissonReconstruction.h>
    #include <vtkPowerCrustSurfaceReconstruction.h>

    #include <vtkPointData.h>

    #include <vtkCoordinate.h>
    #include <vtkTextMapper.h>
    #include <vtkTextProperty.h>
    #include <vtkActor2D.h>

    #include <vtkPolyLine.h>
    #include <vtkActor.h>
    #include <vtkPolyDataMapper2D.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkProperty2D.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkCamera.h>

    #include <vtkNamedColors.h>
    #include <vtkTimerLog.h>
    #include <vtksys/SystemTools.hxx>

    #include <sstream>
    #include <vector>
    #include <string>

    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
    vtkSmartPointer<vtkPolyDataAlgorithm> MakeExtractSurface(vtkPolyData *);
    vtkSmartPointer<vtkPolyDataAlgorithm> MakePoissonExtractSurface(vtkPolyData *);
    vtkSmartPointer<vtkPolyDataAlgorithm> MakePowercrustExtractSurface(vtkPolyData *);
    void MakeViewportGrid(
      std::vector<vtkSmartPointer<vtkRenderer>> &renderers,
      unsigned int renderersize,
      unsigned int xGridDimensions,
      unsigned int yGridDimensions);
    void ViewportBorder(vtkSmartPointer<vtkRenderer> &renderer,
                        double *color,
                        bool last = false);
    }

    int main (int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");;
      std::cout << "# of points: " << polyData->GetNumberOfPoints() << std::endl;

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();

      std::vector<vtkSmartPointer<vtkPolyDataAlgorithm> > surfaceObjects;
      surfaceObjects.push_back(MakeExtractSurface(polyData.GetPointer()));
      surfaceObjects.push_back(MakePoissonExtractSurface(polyData.GetPointer()));
      surfaceObjects.push_back(MakePowercrustExtractSurface(polyData.GetPointer()));

      std::vector<vtkSmartPointer<vtkRenderer>> renderers;

      // One camera for all
      vtkSmartPointer<vtkCamera> camera =
        vtkSmartPointer<vtkCamera>::New();
      for (size_t i = 0; i < surfaceObjects.size(); ++i)
      {
        vtkSmartPointer<vtkTimerLog> timer =
          vtkSmartPointer<vtkTimerLog>::New();
        timer->StartTimer();
        surfaceObjects[i]->Update();
        timer->StopTimer();

        vtkSmartPointer<vtkPolyDataMapper> surfaceMapper =
          vtkSmartPointer<vtkPolyDataMapper>::New();
        surfaceMapper->SetInputConnection(surfaceObjects[i]->GetOutputPort());

        vtkSmartPointer<vtkProperty> back =
          vtkSmartPointer<vtkProperty>::New();
        back->SetDiffuseColor(colors->GetColor3d("banana").GetData());
        back->SetSpecular(.6);
        back->SetSpecularPower(50.0);

        vtkSmartPointer<vtkActor> surfaceActor =
          vtkSmartPointer<vtkActor>::New();
        surfaceActor->SetMapper(surfaceMapper);
        surfaceActor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Tomato").GetData());
        surfaceActor->GetProperty()->SetSpecular(.6);
        surfaceActor->GetProperty()->SetSpecularPower(50.0);
        surfaceActor->SetBackfaceProperty(back);
        // Setup renderer
        vtkSmartPointer<vtkRenderer> renderer =
          vtkSmartPointer<vtkRenderer>::New();
        renderer->AddActor(surfaceActor);
        renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());
        renderer->SetActiveCamera(camera);
        renderer->GetActiveCamera()->SetPosition (-1, 0, 0);
        renderer->GetActiveCamera()->SetFocalPoint (0, 1, 0);
        renderer->GetActiveCamera()->SetViewUp (0, 0, 1);
        renderer->GetActiveCamera()->Dolly(5);
        renderer->ResetCamera();
        renderer->ResetCameraClippingRange();
        renderers.push_back(renderer);
        renderWindow->AddRenderer(renderer);

        vtkSmartPointer<vtkTextProperty> textProperty =
          vtkSmartPointer<vtkTextProperty>::New();
        textProperty->SetFontSize(15);
        textProperty->SetJustificationToCentered();

        std::stringstream ss;
        ss << surfaceObjects[i]->GetClassName() << std::endl;
        ss << "# of Polys: " << surfaceObjects[i]->GetOutput()->GetNumberOfPolys() << std::endl;
        ss << "Time: " << timer->GetElapsedTime() << std::endl;

        vtkSmartPointer<vtkTextMapper> textMapper =
          vtkSmartPointer<vtkTextMapper>::New();
        textMapper->SetInput(ss.str().c_str());
        textMapper->SetTextProperty(textProperty);

        vtkSmartPointer<vtkActor2D> textActor =
          vtkSmartPointer<vtkActor2D>::New();
        textActor->SetMapper(textMapper);
        textActor->SetPosition(200, 0);
        textActor->GetProperty()->SetLineWidth(4.0); // Line Width

        renderer->AddViewProp(textActor);
      }

      unsigned int rendererSize = 400;
      unsigned int xGridDimensions = 3;
      unsigned int yGridDimensions = 1;
      renderWindow->SetSize(
        rendererSize * xGridDimensions,
        rendererSize * yGridDimensions);

      MakeViewportGrid(renderers,
                       rendererSize,
                       xGridDimensions,
                       yGridDimensions);
      for (size_t i = 0; i < renderers.size(); ++i)
      {
        ViewportBorder(renderers[i],
                      colors->GetColor3d("Gold").GetData(),
                      i == renderers.size() - 1);
      }
      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renderWindow);

      iren->Initialize();
      iren->Start();

      return EXIT_SUCCESS;
    }

    namespace {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
    {
      vtkSmartPointer<vtkPolyData> polyData;
      std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
      if (extension == ".ply")
      {
        vtkSmartPointer<vtkPLYReader> reader =
          vtkSmartPointer<vtkPLYReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtp")
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".obj")
      {
        vtkSmartPointer<vtkOBJReader> reader =
          vtkSmartPointer<vtkOBJReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".stl")
      {
        vtkSmartPointer<vtkSTLReader> reader =
          vtkSmartPointer<vtkSTLReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".g")
      {
        vtkSmartPointer<vtkBYUReader> reader =
          vtkSmartPointer<vtkBYUReader>::New();
        reader->SetGeometryFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".g")
      {
        vtkSmartPointer<vtkBYUReader> reader =
          vtkSmartPointer<vtkBYUReader>::New();
        reader->SetGeometryFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkPointSource> points =
          vtkSmartPointer<vtkPointSource>::New();
     points->SetNumberOfPoints(1000);
        points->SetRadius(1.0);
        points->SetCenter(vtkMath::Random(-1, 1),
                          vtkMath::Random(-1, 1),
                          vtkMath::Random(-1, 1));
        points->SetDistributionToShell();
        points->Update();
        polyData = points->GetOutput();
      }
      return polyData;
    }

    vtkSmartPointer<vtkPolyDataAlgorithm> MakeExtractSurface(vtkPolyData *polyData)
    {
      double bounds[6];
      polyData->GetBounds(bounds);
      double range[3];
      for (int i = 0; i < 3; ++i)
      {
        range[i] = bounds[2*i + 1] - bounds[2*i];
      }

      int sampleSize = polyData->GetNumberOfPoints() * .00005;
      if (sampleSize < 10)
      {
        sampleSize = 50;
      }

      // Do we need to estimate normals?
      vtkSmartPointer<vtkSignedDistance> distance =
        vtkSmartPointer<vtkSignedDistance>::New();
      if (polyData->GetPointData()->GetNormals())
      {
        std::cout << "ExtractSurface: Using normals from input file" << std::endl;
        distance->SetInputData (polyData);
      }
      else
      {
        std::cout <<" ExtractSurface: Estimating normals using PCANormalEstimation" << std::endl;
        vtkSmartPointer<vtkPCANormalEstimation> normals =
          vtkSmartPointer<vtkPCANormalEstimation>::New();
        normals->SetInputData (polyData);
        normals->SetSampleSize(sampleSize);
        normals->SetNormalOrientationToGraphTraversal();
        normals->FlipNormalsOn();
        distance->SetInputConnection (normals->GetOutputPort());
      }
      int dimension = 256;
      double radius;
      radius = std::max(std::max(range[0], range[1]), range[2])
        / static_cast<double>(dimension) * 4; // ~4 voxels

      distance->SetRadius(radius);
      distance->SetDimensions(dimension, dimension, dimension);
      distance->SetBounds(
        bounds[0] - range[0] * .1,
        bounds[1] + range[0] * .1,
        bounds[2] - range[1] * .1,
        bounds[3] + range[1] * .1,
        bounds[4] - range[2] * .1,
        bounds[5] + range[2] * .1);

      vtkSmartPointer<vtkExtractSurface> surface =
        vtkSmartPointer<vtkExtractSurface>::New();
      surface->SetInputConnection (distance->GetOutputPort());
      surface->SetRadius(radius * .99);
      return surface;
    }
    vtkSmartPointer<vtkPolyDataAlgorithm> MakePoissonExtractSurface(vtkPolyData *polyData)
    {
      double bounds[6];
      polyData->GetBounds(bounds);
      double range[3];
      for (int i = 0; i < 3; ++i)
      {
        range[i] = bounds[2*i + 1] - bounds[2*i];
      }

      int sampleSize = polyData->GetNumberOfPoints() * .00005;
      if (sampleSize < 10)
      {
        sampleSize = 10;
      }

      vtkSmartPointer<vtkPoissonReconstruction> surface =
        vtkSmartPointer<vtkPoissonReconstruction>::New();
      surface->SetDepth(12);
      if (polyData->GetPointData()->GetNormals())
      {
        std::cout << "PoissonReconstruction: Using normals from input file" << std::endl;
        surface->SetInputData (polyData);
      }
      else
      {
        std::cout << "ExtractSurface: Estimating normals using PCANormalEstimation" << std::endl;
        vtkSmartPointer<vtkPCANormalEstimation> normals =
          vtkSmartPointer<vtkPCANormalEstimation>::New();
        normals->SetInputData (polyData);
        normals->SetSampleSize(sampleSize);
        normals->SetNormalOrientationToGraphTraversal();
        normals->FlipNormalsOff();
        surface->SetInputConnection(normals->GetOutputPort());
      }
      return surface;
    }
    vtkSmartPointer<vtkPolyDataAlgorithm> MakePowercrustExtractSurface(vtkPolyData *polyData)
    {
      vtkSmartPointer<vtkPowerCrustSurfaceReconstruction> surface =
        vtkSmartPointer<vtkPowerCrustSurfaceReconstruction>::New();
      surface->SetInputData (polyData);
      return surface;
    }

    void MakeViewportGrid(
      std::vector<vtkSmartPointer<vtkRenderer>> &renderers,
      unsigned int rendererSize,
      unsigned int xGridDimensions,
      unsigned int yGridDimensions)
    {
      //
      // Setup viewports for the renderers
      int index = 0;
      for (int row = 0; row < static_cast<int>(yGridDimensions); row++)
      {
        for (int col = 0; col < static_cast<int>(xGridDimensions); col++)
        {
          int index = row * xGridDimensions + col;

          // (xmin, ymin, xmax, ymax)
          double viewport[4] = {
            static_cast<double>(col) * rendererSize /
            (xGridDimensions * rendererSize),
            static_cast<double>(yGridDimensions - (row + 1)) * rendererSize /
            (yGridDimensions * rendererSize),
            static_cast<double>(col + 1) * rendererSize /
            (xGridDimensions * rendererSize),
            static_cast<double>(yGridDimensions - row) * rendererSize /
            (yGridDimensions * rendererSize)};
          renderers[index]->SetViewport(viewport);
        }
      }
    }
    // draw the borders of a renderer's viewport
    void ViewportBorder(vtkSmartPointer<vtkRenderer> &renderer,
                        double *color,
                        bool last)
    {
      // points start at upper right and proceed anti-clockwise
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->SetNumberOfPoints(4);
      points->InsertPoint(0, 1, 1, 0);
      points->InsertPoint(1, 0, 1, 0);
      points->InsertPoint(2, 0, 0, 0);
      points->InsertPoint(3, 1, 0, 0);

      // create cells, and lines
      vtkSmartPointer<vtkCellArray> cells =
        vtkSmartPointer<vtkCellArray>::New();
      cells->Initialize();

      vtkSmartPointer<vtkPolyLine> lines =
        vtkSmartPointer<vtkPolyLine>::New();

      // only draw last line if this is the last viewport
      // this prevents double vertical lines at right border
      // if different colors are used for each border, then do
      // not specify last
      if (last)
      {
        lines->GetPointIds()->SetNumberOfIds(5);
      }
      else
      {
      lines->GetPointIds()->SetNumberOfIds(4);
      }
      for(unsigned int i = 0; i < 4; ++i)
      {
        lines->GetPointIds()->SetId(i,i);
      }
      if (last)
      {
        lines->GetPointIds()->SetId(4, 0);
      }
      cells->InsertNextCell(lines);

      // now make the polydata and display it
      vtkSmartPointer<vtkPolyData> poly =
        vtkSmartPointer<vtkPolyData>::New();
      poly->Initialize();
      poly->SetPoints(points);
      poly->SetLines(cells);

      // use normalized viewport coordinates since
      // they are independent of window size
      vtkSmartPointer<vtkCoordinate> coordinate =
        vtkSmartPointer<vtkCoordinate>::New();
      coordinate->SetCoordinateSystemToNormalizedViewport();

      vtkSmartPointer<vtkPolyDataMapper2D> mapper =
        vtkSmartPointer<vtkPolyDataMapper2D>::New();
      mapper->SetInputData(poly);
      mapper->SetTransformCoordinate(coordinate);

      vtkSmartPointer<vtkActor2D> actor =
        vtkSmartPointer<vtkActor2D>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetColor(color);
      // line width should be at least 2 to be visible at extremes

      actor->GetProperty()->SetLineWidth(4.0); // Line Width

      renderer->AddViewProp(actor);
    }

    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(CompareExtractSurface)

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

### Download and Build CompareExtractSurface

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

    cd CompareExtractSurface/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:

    ./CompareExtractSurface

WINDOWS USERS

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