# Vertex

VTKExamples/Cxx/GeometricObjects/Vertex

### Description

The vertex is a primary zero-dimensional cell. It is defined by a single point.

### Code

Vertex.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>
    #include <vtkPoints.h>
    #include <vtkCellArray.h>
    #include <vtkVertex.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(0,0,0);

      vtkSmartPointer<vtkVertex> vertex =
        vtkSmartPointer<vtkVertex>::New();
      vertex->GetPointIds()->SetId(0, 0);

      vtkSmartPointer<vtkCellArray> vertices =
        vtkSmartPointer<vtkCellArray>::New();
      vertices->InsertNextCell(vertex);

      vtkSmartPointer<vtkPolyData> polydata =
        vtkSmartPointer<vtkPolyData>::New();
      polydata->SetPoints(points);
      polydata->SetVerts(vertices);

      // Setup actor and mapper
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      mapper->SetInputConnection(polydata->GetProducerPort());
    #else
      mapper->SetInputData(polydata);
    #endif

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetPointSize(10);

      // Setup render window, renderer, 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);
      renderer->AddActor(actor);

      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Vertex)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(Vertex MACOSX_BUNDLE Vertex.cxx )

    target_link_libraries(Vertex ${VTK_LIBRARIES})

### Download and Build Vertex

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

    cd Vertex/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:

    ./Vertex

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