# WarpVector

VTKExamples/Cxx/PolyData/WarpVector

Other Languages

See (Python), (CSharp)

### Code

WarpVector.cxx

    #include <vtkActor.h>
    #include <vtkCellArray.h>
    #include <vtkDoubleArray.h>
    #include <vtkLine.h>
    #include <vtkPointData.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>
    #include <vtkWarpVector.h>

    int main(int, char *[])
    {

      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(0.0, 0.0, 0.0);
      points->InsertNextPoint(1.0, 0.0, 0.0);
      points->InsertNextPoint(2.0, 0.0, 0.0);
      points->InsertNextPoint(3.0, 0.0, 0.0);
      points->InsertNextPoint(4.0, 0.0, 0.0);

      vtkSmartPointer<vtkCellArray> lines =
        vtkSmartPointer<vtkCellArray>::New();
      vtkSmartPointer<vtkLine> line =
        vtkSmartPointer<vtkLine>::New();
      line->GetPointIds()->SetId(0, 0);
      line->GetPointIds()->SetId(1, 1);
      lines->InsertNextCell(line);
      line->GetPointIds()->SetId(0, 1);
      line->GetPointIds()->SetId(1, 2);
      lines->InsertNextCell(line);
      line->GetPointIds()->SetId(0, 2);
      line->GetPointIds()->SetId(1, 3);
      lines->InsertNextCell(line);
      line->GetPointIds()->SetId(0, 3);
      line->GetPointIds()->SetId(1, 4);
      lines->InsertNextCell(line);

      vtkSmartPointer<vtkDoubleArray> warpData =
        vtkSmartPointer<vtkDoubleArray>::New();
      warpData->SetNumberOfComponents(3);
      warpData->SetName("warpData");
      double warp[3] = {0.0, 0.0, 0.0};
      warp[1] = 0.0;
      warpData->InsertNextTuple(warp);
      warp[1] = 0.1;
      warpData->InsertNextTuple(warp);
      warp[1] = 0.3;
      warpData->InsertNextTuple(warp);
      warp[1] = 0.0;
      warpData->InsertNextTuple(warp);
      warp[1] = 0.1;
      warpData->InsertNextTuple(warp);

      vtkSmartPointer<vtkPolyData> polydata =
        vtkSmartPointer<vtkPolyData>::New();
      polydata->SetPoints(points);
      polydata->SetLines(lines);
      polydata->GetPointData()->AddArray(warpData);
      polydata->GetPointData()->SetActiveVectors(warpData->GetName());

      //WarpVector will use the array marked as active vector in polydata
      //it has to be a 3 component array
      //with the same number of tuples as points in polydata
      vtkSmartPointer<vtkWarpVector> warpVector =
        vtkSmartPointer<vtkWarpVector>::New();
      warpVector->SetInputData(polydata);
      warpVector->Update();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputData(warpVector->GetPolyDataOutput());

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

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

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

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(WarpVector)

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

### Download and Build WarpVector

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

    cd WarpVector/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:

    ./WarpVector

WINDOWS USERS

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