# DEMReader

VTKExamples/Cxx/IO/DEMReader

### Code

DEMReader.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageActor.h>
    #include <vtkImageMapToColors.h>
    #include <vtkLookupTable.h>
    #include <vtkDEMReader.h>
    #include <vtkImageData.h>
    #include <vtkImageMapper3D.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>

    int main(int argc, char* argv[])
    {
      // Verify arguments
      if(argc < 2)
      {
        std::cerr << "Required: filename.dem" << std::endl;
        return EXIT_FAILURE;
      }

      // Read the file
      vtkSmartPointer<vtkDEMReader> reader =
        vtkSmartPointer<vtkDEMReader>::New();
      reader->SetFileName(argv[1]);
      reader->Update();

      vtkSmartPointer<vtkLookupTable> lut =
        vtkSmartPointer<vtkLookupTable>::New();
      lut->SetHueRange(0.6, 0);
      lut->SetSaturationRange(1.0, 0);
      lut->SetValueRange(0.5, 1.0);
      lut->SetTableRange(reader->GetOutput()->GetScalarRange());

      // Visualize
      vtkSmartPointer<vtkImageMapToColors> mapColors =
        vtkSmartPointer<vtkImageMapToColors>::New();
      mapColors->SetLookupTable(lut);
      mapColors->SetInputConnection(reader->GetOutputPort());

      // Create an actor
      vtkSmartPointer<vtkImageActor> actor =
        vtkSmartPointer<vtkImageActor>::New();
      actor->GetMapper()->SetInputConnection(mapColors->GetOutputPort());

      // Setup renderer
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);
      renderer->ResetCamera();

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      // Render and start interaction
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(DEMReader)

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

    add_executable(DEMReader MACOSX_BUNDLE DEMReader.cxx )

    target_link_libraries(DEMReader ${VTK_LIBRARIES})

### Download and Build DEMReader

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

    cd DEMReader/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:

    ./DEMReader

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.