# ReadUnknownTypeXMLFile

VTKExamples/Cxx/IO/ReadUnknownTypeXMLFile

### Description

This examples reads either a vtu (unstructured grid) or vtp (polydata) file and displays it to the screen.

### Code

ReadUnknownTypeXMLFile.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyData.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkDataSetMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkXMLGenericDataObjectReader.h>

    int main(int argc, char *argv[])
    {
      // Ensure a filename was specified
      if(argc < 2)
      {
        std::cerr << "Required arguments: InputFilename" << std::endl;
        return EXIT_FAILURE;
      }

      // Get the filename from the command line
      std::string inputFilename = argv[1];

      // Get all data from the file
      vtkSmartPointer<vtkXMLGenericDataObjectReader> reader =
        vtkSmartPointer<vtkXMLGenericDataObjectReader>::New();
      reader->SetFileName(inputFilename.c_str());
      reader->Update();

      // All of the standard data types can be checked and obtained like this:
      if(vtkPolyData::SafeDownCast(reader->GetOutput()))
      {
        std::cout << "File is a polydata" << std::endl;
      }
      else if(vtkUnstructuredGrid::SafeDownCast(reader->GetOutput()))
      {
        std::cout << "File is an unstructured grid" << std::endl;
      }

      // Visualize
      vtkSmartPointer<vtkDataSetMapper> mapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      mapper->SetInputConnection(reader->GetOutputPort());

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

      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);
      renderer->SetBackground(.3, .6, .3); // Background color green

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ReadUnknownTypeXMLFile)

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

    add_executable(ReadUnknownTypeXMLFile MACOSX_BUNDLE ReadUnknownTypeXMLFile.cxx )

    target_link_libraries(ReadUnknownTypeXMLFile ${VTK_LIBRARIES})

### Download and Build ReadUnknownTypeXMLFile

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

    cd ReadUnknownTypeXMLFile/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:

    ./ReadUnknownTypeXMLFile

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.