# BrownianPoints

VTKExamples/Cxx/Utilities/BrownianPoints

### Code

BrownianPoints.cxx

    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkArrowSource.h>
    #include <vtkBrownianPoints.h>
    #include <vtkCamera.h>
    #include <vtkGlyph3D.h>
    #include <vtkMath.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSphereSource.h>

    #include <vtkNamedColors.h>

    int main(int, char *[])
    {
      // Create a sphere
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();

      // Generate random vectors
      vtkMath::RandomSeed(5070); // for testing
      vtkSmartPointer<vtkBrownianPoints> brownianPoints =
        vtkSmartPointer<vtkBrownianPoints>::New();
      brownianPoints->SetInputConnection(sphereSource->GetOutputPort());

      vtkSmartPointer<vtkArrowSource> arrowSource =
        vtkSmartPointer<vtkArrowSource>::New();

      vtkSmartPointer<vtkGlyph3D> glyph3D =
        vtkSmartPointer<vtkGlyph3D>::New();
      glyph3D->SetSourceConnection(arrowSource->GetOutputPort());
      glyph3D->SetInputConnection(brownianPoints->GetOutputPort());
      glyph3D->SetScaleFactor(.3);

      // Create a mapper and actor for sphere
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(sphereSource->GetOutputPort());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->GetProperty()->EdgeVisibilityOn();
      actor->GetProperty()->SetInterpolationToFlat();
      actor->SetMapper(mapper);

      // Create a mapper and actor for glyphs
      vtkSmartPointer<vtkPolyDataMapper> glyphMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      glyphMapper->SetInputConnection(glyph3D->GetOutputPort());

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

      vtkSmartPointer<vtkActor> glyphActor =
        vtkSmartPointer<vtkActor>::New();
      glyphActor->GetProperty()->SetColor(colors->GetColor3d("banana").GetData());
      glyphActor->SetMapper(glyphMapper);

      //Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      //Add the actor to the scene
      renderer->AddActor(actor);
      renderer->AddActor(glyphActor);

      // Create a nice view
      renderer->ResetCamera();
      renderer->GetActiveCamera()->Azimuth(30);
      renderer->GetActiveCamera()->Elevation(30);
      renderer->GetActiveCamera()->Dolly(1.4);
      renderer->ResetCameraClippingRange();

      renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

      //Render and interact
      renderWindow->SetSize(640, 480);
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(BrownianPoints)

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

### Download and Build BrownianPoints

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

    cd BrownianPoints/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:

    ./BrownianPoints

WINDOWS USERS

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