ReadTextFile

Description¶

This example takes a plain text file of coordinates and reads them into a vtkPoints, which is then put into a vtkPolyData and displayed on the screen using a vtkVertexGlyphFilter.

An example file may look like: 1 2 3 4 5 6 7 8 9

Note

for a simpler way to read such a file, see SimplePointsReader.

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

ReadTextFile.cxx

#include <vtkActor.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkVertexGlyphFilter.h>

#include <sstream>

int main(int argc, char* argv[])
{
  vtkNew<vtkNamedColors> colors;

  // Verify input arguments
  if (argc != 2)
  {
    std::cout << "Usage: " << argv[0] << " Filename(.txt) e.g. TeapotPoints.txt"
              << std::endl;
    return EXIT_FAILURE;
  }
  // Get all data from the file
  std::string filename = argv[1];
  std::ifstream filestream(filename.c_str());

  std::string line;
  vtkNew<vtkPoints> points;

  while (std::getline(filestream, line))
  {
    double x, y, z;
    std::stringstream linestream;
    linestream << line;
    linestream >> x >> y >> z;

    points->InsertNextPoint(x, y, z);
  }

  filestream.close();

  vtkNew<vtkPolyData> polyData;

  polyData->SetPoints(points);

  vtkNew<vtkVertexGlyphFilter> glyphFilter;
  glyphFilter->SetInputData(polyData);
  glyphFilter->Update();

  // Visualize

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(glyphFilter->GetOutputPort());

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("MidnightBlue").GetData());

  vtkNew<vtkRenderer> renderer;
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("Gainsboro").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("ReadTextFile");

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

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

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ReadTextFile)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ReadTextFile: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(ReadTextFile MACOSX_BUNDLE ReadTextFile.cxx )
  target_link_libraries(ReadTextFile PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ReadTextFile
  MODULES ${VTK_LIBRARIES}
)

Download and Build ReadTextFile¶

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

cd ReadTextFile/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:

./ReadTextFile

WINDOWS USERS

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