# SimplePointsReader

VTKExamples/Cxx/IO/SimplePointsReader

### Description

A file of XYZ coordinates is a very easy format that can be used for simple storage from many applications. This example demonstrates how to read this type of file into a polydata object. An example file of three points would look like this:

`0.0 0.0 0.0 1.0 0.0 0.0 0.0 1.0 0.0`

As a demo, save the above three lines to a file called simple.xyz and call the executable resulting from the code below with

`./SimplePointsReader simple.xyz`

from the build directory.

Seealso

For the reverse operation, writing a points file, see the SimplePointsWriter example.

Other Languages

See (CSharp)

### Code

SimplePointsReader.cxx

    #include <vtkSmartPointer.h>
    #include <vtkSimplePointsReader.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>

    int main(int argc, char* argv[])
    {
      // Verify input arguments
      if ( argc != 2 )
      {
        std::cout << "Usage: " << argv[0]
                  << " Filename(.xyz)" << std::endl;
        return EXIT_FAILURE;
      }

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

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

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetPointSize(4);

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);
      renderer->SetBackground(.3, .6, .3); // Background color green

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(SimplePointsReader)

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

### Download and Build SimplePointsReader

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

    cd SimplePointsReader/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:

    ./SimplePointsReader

WINDOWS USERS

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