# PointLocatorRadius

VTKExamples/Cxx/PolyData/PointLocatorRadius

### Code

PointLocatorRadius.cxx

    #include <vtkSmartPointer.h>
    #include <vtkIdList.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkObjectFactory.h>
    #include <vtkPointSource.h>
    #include <vtkPolyData.h>
    #include <vtkPointLocator.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkPointSource> pointSource =
        vtkSmartPointer<vtkPointSource>::New();
      pointSource->SetNumberOfPoints(400);
      pointSource->Update();

      // Create the tree
      vtkSmartPointer<vtkPointLocator> pointLocator =
        vtkSmartPointer<vtkPointLocator>::New();
      pointLocator->SetDataSet(pointSource->GetOutput());
      pointLocator->AutomaticOn();
      pointLocator->SetNumberOfPointsPerBucket(2);
      pointLocator->BuildLocator();

      double radius = .1;
      double center[3] = {0.0, 0.0, 0.0};
      vtkSmartPointer<vtkIdList> result =
        vtkSmartPointer<vtkIdList>::New();
      pointLocator->FindPointsWithinRadius (radius, center, result);

      for(vtkIdType i = 0; i < result->GetNumberOfIds(); i++)
      {
        unsigned int id = result->GetId(i);
        std::cout << "id of point " << i << " : " << id << std::endl;
      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(PointLocatorRadius)

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

### Download and Build PointLocatorRadius

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

    cd PointLocatorRadius/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:

    ./PointLocatorRadius

WINDOWS USERS

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