VectorNorm

VTKEx/Cxx/Math/VectorNorm

Question

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Code

VectorNorm.cxx

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkFloatArray.h>
#include <vtkPointData.h>
#include <vtkVectorNorm.h>

// For compatibility with new VTK generic data arrays
#ifdef vtkGenericDataArray_h
#define InsertNextTupleValue InsertNextTypedTuple
#endif

int main(int, char *[])
{
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(1,2,3);
  points->InsertNextPoint(4,5,6);

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

  vtkSmartPointer<vtkFloatArray> distances =
    vtkSmartPointer<vtkFloatArray>::New();
  distances->SetNumberOfComponents(3);
  distances->SetName("Distances");

  float v1[3] = {1,2,3};
  float v2[3] = {4,5,6};
  distances->InsertNextTupleValue(v1);
  distances->InsertNextTupleValue(v2);

  polydata->GetPointData()->SetVectors(distances);

  vtkSmartPointer<vtkVectorNorm> vectorNorm =
    vtkSmartPointer<vtkVectorNorm>::New();
  vectorNorm->SetInputData(polydata);
  vectorNorm->Update();

  vtkFloatArray* scalars = dynamic_cast<vtkFloatArray*> ( vectorNorm->GetOutput()->GetPointData()->GetScalars() );

  for(vtkIdType i = 0; i < scalars->GetNumberOfTuples(); i++)
  {
    std::cout << "Value " << i << " : " << scalars->GetValue(i) << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(VectorNorm)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersCore QUIET)
if (NOT VTK_FOUND)
  message("Skipping VectorNorm: ${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(VectorNorm MACOSX_BUNDLE VectorNorm.cxx )
  target_link_libraries(VectorNorm PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(VectorNorm MACOSX_BUNDLE VectorNorm.cxx )
  target_link_libraries(VectorNorm PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS VectorNorm
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build VectorNorm

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

cd VectorNorm/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:

./VectorNorm

WINDOWS USERS

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