ColorDisconnectedRegionsDemo

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkLookupTable.h>
#include <vtkMinimalStandardRandomSequence.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyDataConnectivityFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>

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

// #include <random>
#include <vtksys/SystemTools.hxx>

namespace {
vtkSmartPointer<vtkPolyData> ReadPolyData(const char* fileName);
void RandomColors(vtkLookupTable* lut, int numberOfColors);
} // namespace

int main(int argc, char* argv[])
{
  vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");

  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkPolyDataConnectivityFilter> connectivityFilter;
  connectivityFilter->SetInputData(polyData);
  connectivityFilter->SetExtractionModeToAllRegions();
  connectivityFilter->ColorRegionsOn();
  connectivityFilter->Update();

  // Visualize.
  auto numberOfRegions = connectivityFilter->GetNumberOfExtractedRegions();
  vtkNew<vtkLookupTable> lut;
  lut->SetNumberOfTableValues(std::max(numberOfRegions, 10));
  lut->Build();
  RandomColors(lut, numberOfRegions);

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(connectivityFilter->GetOutputPort());
  mapper->SetScalarRange(connectivityFilter->GetOutput()
                             ->GetPointData()
                             ->GetArray("RegionId")
                             ->GetRange());
  mapper->SetLookupTable(lut);
  mapper->Update();

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);

  vtkNew<vtkRenderer> renderer;
  renderer->UseHiddenLineRemovalOn();
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("Silver").GetData());

  // Create a useful view.
  renderer->ResetCamera();
  renderer->GetActiveCamera()->Azimuth(30);
  renderer->GetActiveCamera()->Elevation(30);
  renderer->GetActiveCamera()->Dolly(1.2);
  renderer->ResetCameraClippingRange();

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetSize(640, 480);
  renderWindow->SetWindowName("ColorDisconnectedRegions");

  vtkNew<vtkInteractorStyleTrackballCamera> style;
  vtkNew<vtkRenderWindowInteractor> interactor;
  interactor->SetInteractorStyle(style);
  interactor->SetRenderWindow(renderWindow);
  renderWindow->Render();
  interactor->Initialize();
  interactor->Start();

  return EXIT_SUCCESS;
}

namespace {
vtkSmartPointer<vtkPolyData> ReadPolyData(const char* fileName)
{
  vtkSmartPointer<vtkPolyData> polyData;
  std::string extension =
      vtksys::SystemTools::GetFilenameLastExtension(std::string(fileName));
  if (extension == ".ply")
  {
    vtkNew<vtkPLYReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtp")
  {
    vtkNew<vtkXMLPolyDataReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".obj")
  {
    vtkNew<vtkOBJReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".stl")
  {
    vtkNew<vtkSTLReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtk")
  {
    vtkNew<vtkPolyDataReader> reader;
    reader->SetFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".g")
  {
    vtkNew<vtkBYUReader> reader;
    reader->SetGeometryFileName(fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else
  {
    vtkNew<vtkSphereSource> source;
    source->Update();
    polyData = source->GetOutput();
  }
  return polyData;
}

void RandomColors(vtkLookupTable* lut, int numberOfColors)
{
  // Fill in a few known colors, the rest will be generated if needed.
  vtkNew<vtkNamedColors> colors;
  lut->SetTableValue(0, colors->GetColor4d("Gold").GetData());
  lut->SetTableValue(1, colors->GetColor4d("Banana").GetData());
  lut->SetTableValue(2, colors->GetColor4d("Tomato").GetData());
  lut->SetTableValue(3, colors->GetColor4d("Wheat").GetData());
  lut->SetTableValue(4, colors->GetColor4d("Lavender").GetData());
  lut->SetTableValue(5, colors->GetColor4d("Flesh").GetData());
  lut->SetTableValue(6, colors->GetColor4d("Raspberry").GetData());
  lut->SetTableValue(7, colors->GetColor4d("Salmon").GetData());
  lut->SetTableValue(8, colors->GetColor4d("Mint").GetData());
  lut->SetTableValue(9, colors->GetColor4d("Peacock").GetData());

  // If the number of colors is larger than the number of specified colors,
  // generate some random colors.
  vtkNew<vtkMinimalStandardRandomSequence> randomSequence;
  randomSequence->SetSeed(4355412);
  if (numberOfColors > 9)
  {
    for (auto i = 10; i < numberOfColors; ++i)
    {
      double r, g, b;
      r = randomSequence->GetRangeValue(0.6, 1.0);
      randomSequence->Next();
      g = randomSequence->GetRangeValue(0.6, 1.0);
      randomSequence->Next();
      b = randomSequence->GetRangeValue(0.6, 1.0);
      randomSequence->Next();
      lut->SetTableValue(i, r, g, b, 1.0);
    }
  }
}
} // namespace

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ColorDisconnectedRegionsDemo)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ColorDisconnectedRegionsDemo: 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(ColorDisconnectedRegionsDemo MACOSX_BUNDLE ColorDisconnectedRegionsDemo.cxx )
  target_link_libraries(ColorDisconnectedRegionsDemo PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ColorDisconnectedRegionsDemo
  MODULES ${VTK_LIBRARIES}
)

cd ColorDisconnectedRegionsDemo/build

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./ColorDisconnectedRegionsDemo