# ParametricSpline

VTKExamples/Cxx/PolyData/ParametricSpline

### Code

ParametricSpline.cxx

    #include <vtkSmartPointer.h>
    #include <vtkParametricFunctionSource.h>
    #include <vtkParametricSpline.h>

    #include <vtkCellArray.h>
    #include <vtkCellData.h>
    #include <vtkDoubleArray.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkCamera.h>
    #include <vtkProperty.h>

    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkGlyph3DMapper.h>

    #include <vtkSphereSource.h>
    #include <vtkNamedColors.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      // Create three points. We will join (Origin and P0) with a red line and (Origin and P1) with a green line
      double origin[3] = {0.0, 0.0, 0.0};
      double p0[3] = {1.0, 0.0, 0.0};
      double p1[3] = {0.0, 1.0, 0.0};
      double p2[3] = {0.0, 1.0, 2.0};
      double p3[3] = {1.0, 2.0, 3.0};

      // Create a vtkPoints object and store the points in it
      vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(origin);
      points->InsertNextPoint(p0);
      points->InsertNextPoint(p1);
      points->InsertNextPoint(p2);
      points->InsertNextPoint(p3);

      vtkSmartPointer<vtkParametricSpline> spline =
        vtkSmartPointer<vtkParametricSpline>::New();
      spline->SetPoints(points);

      vtkSmartPointer<vtkParametricFunctionSource> functionSource =
        vtkSmartPointer<vtkParametricFunctionSource>::New();
      functionSource->SetParametricFunction(spline);
      functionSource->Update();

      vtkSmartPointer<vtkSphereSource> sphere =
        vtkSmartPointer<vtkSphereSource>::New();
      sphere->SetPhiResolution(21);
      sphere->SetThetaResolution(21);
      sphere->SetRadius(.1);

      // Setup actor and mapper
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(functionSource->GetOutputPort());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetColor(colors->GetColor3d("DarkSlateGrey").GetData());
      actor->GetProperty()->SetLineWidth(3.0);

      // Create a polydata to store everything in
      vtkSmartPointer<vtkPolyData> polyData =
        vtkSmartPointer<vtkPolyData>::New();
      polyData->SetPoints(points);

      vtkSmartPointer<vtkGlyph3DMapper> pointMapper =
        vtkSmartPointer<vtkGlyph3DMapper>::New();
      pointMapper->SetInputData(polyData);
      pointMapper->SetSourceConnection(sphere->GetOutputPort());

      vtkSmartPointer<vtkActor> pointActor =
        vtkSmartPointer<vtkActor>::New();
      pointActor->SetMapper(pointMapper);
      pointActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

      // Setup render window, renderer, and interactor
      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->AddActor(pointActor);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ParametricSpline)

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

### Download and Build ParametricSpline

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

    cd ParametricSpline/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:

    ./ParametricSpline

WINDOWS USERS

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