# DeformPointSet

VTKExamples/Cxx/Meshes/DeformPointSet

### Description

Deform a point set with a polyhedra. Supply a .vtp file and see it deformed.

### Code

DeformPointSet.cxx

    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkRenderer.h>
    #include <vtkSphereSource.h>
    #include <vtkElevationFilter.h>
    #include <vtkProperty.h>
    #include <vtkCellArray.h>
    #include <vtkPoints.h>
    #include <vtkDeformPointSet.h>
    #include <vtkCamera.h>
    #include <vtkXMLPolyDataReader.h>

    int main( int argc, char *argv[] )
    {
      vtkSmartPointer<vtkPolyData> input =
        vtkSmartPointer<vtkPolyData>::New();
      double bounds[6];

      if(argc == 1)
      {
        // Create a sphere to warp
        vtkSmartPointer<vtkSphereSource> sphere =
          vtkSmartPointer<vtkSphereSource>::New();
        sphere->SetThetaResolution(51);
        sphere->SetPhiResolution(17);
        sphere->Update();
        sphere->GetOutput()->GetBounds(bounds);

        // Generate some scalars on the polydata
        vtkSmartPointer<vtkElevationFilter> ele =
          vtkSmartPointer<vtkElevationFilter>::New();
        ele->SetInputConnection(sphere->GetOutputPort());
        ele->SetLowPoint(0,0,-0.5);
        ele->SetHighPoint(0,0,0.5);
        ele->SetLowPoint((bounds[1] + bounds[0]) / 2.0,
                         (bounds[3] + bounds[2]) / 2.0,
                         -bounds[5]);
        ele->SetHighPoint((bounds[1] + bounds[0]) / 2.0,
                          (bounds[3] + bounds[2]) / 2.0,
                          bounds[5]);

        ele->Update();
        input->ShallowCopy(ele->GetOutput());
      }
      else
      {
        std::string inputFilename = argv[1];

        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName(inputFilename.c_str());
        reader->Update();

        input->ShallowCopy(reader->GetOutput());
        input->GetBounds(bounds);
      }

      // Now create a control mesh, in this case a octagon that encloses
      // the point set
      vtkSmartPointer<vtkPoints> pts =
        vtkSmartPointer<vtkPoints>::New();
      pts->SetNumberOfPoints(6);
      pts->SetPoint(0,
                    bounds[0] - .1 * (bounds[1] - bounds[0]),
                    (bounds[3] + bounds[2]) / 2.0,
                    (bounds[5] + bounds[4]) / 2.0);
      pts->SetPoint(1,
                    bounds[1] + .1 * (bounds[1] - bounds[0]),
                    (bounds[3] + bounds[2]) / 2.0,
                    (bounds[5] + bounds[4]) / 2.0);
      pts->SetPoint(2,
                    (bounds[1] + bounds[0]) / 2.0,
                    bounds[2] - .1 * (bounds[3] - bounds[2]),
                    (bounds[5] + bounds[4]) / 2.0);
      pts->SetPoint(3,
                    (bounds[1] + bounds[0]) / 2.0,
                    bounds[3] + .1 * (bounds[3] - bounds[2]),
                    (bounds[5] + bounds[4]) / 2.0);
      pts->SetPoint(4,
                    (bounds[1] + bounds[0]) / 2.0,
                    (bounds[3] + bounds[2]) / 2.0,
                    bounds[4] - .1 * (bounds[5] - bounds[4]));
      pts->SetPoint(5,
                    (bounds[1] + bounds[0]) / 2.0,
                    (bounds[3] + bounds[2]) / 2.0,
                    bounds[5] + .1 * (bounds[5] - bounds[4]));

      vtkSmartPointer<vtkCellArray> tris =
        vtkSmartPointer<vtkCellArray>::New();
      tris->InsertNextCell(3);
      tris->InsertCellPoint(2); tris->InsertCellPoint(0); tris->InsertCellPoint(4);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(1); tris->InsertCellPoint(2); tris->InsertCellPoint(4);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(3); tris->InsertCellPoint(1); tris->InsertCellPoint(4);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(0); tris->InsertCellPoint(3); tris->InsertCellPoint(4);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(0); tris->InsertCellPoint(2); tris->InsertCellPoint(5);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(2); tris->InsertCellPoint(1); tris->InsertCellPoint(5);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(1); tris->InsertCellPoint(3); tris->InsertCellPoint(5);
      tris->InsertNextCell(3);
      tris->InsertCellPoint(3); tris->InsertCellPoint(0); tris->InsertCellPoint(5);

      vtkSmartPointer<vtkPolyData> pd =
        vtkSmartPointer<vtkPolyData>::New();
      pd->SetPoints(pts);
      pd->SetPolys(tris);

      // Display the control mesh
      vtkSmartPointer<vtkPolyDataMapper> meshMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      meshMapper->SetInputData(pd);
      vtkSmartPointer<vtkActor> meshActor =
        vtkSmartPointer<vtkActor>::New();
      meshActor->SetMapper(meshMapper);
      meshActor->GetProperty()->SetRepresentationToWireframe();
      meshActor->GetProperty()->SetColor(0,0,0);

      // Do the intitial weight generation
      vtkSmartPointer<vtkDeformPointSet> deform =
        vtkSmartPointer<vtkDeformPointSet>::New();
        deform->SetInputData(input);
        deform->SetControlMeshData(pd);
        deform->Update(); // this creates the initial weights

      // Now move one point and deform
      double controlPoint[3];
      pts->GetPoint(5, controlPoint);
      pts->SetPoint(5, controlPoint[0],
                    controlPoint[1],
                    bounds[5] + .8 * (bounds[5] - bounds[4]));
      pts->Modified();

      // Display the warped polydata
      vtkSmartPointer<vtkPolyDataMapper> polyMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
        polyMapper->SetInputConnection(deform->GetOutputPort());
      vtkSmartPointer<vtkActor> polyActor =
        vtkSmartPointer<vtkActor>::New();
        polyActor->SetMapper(polyMapper);

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      renderer->AddActor(polyActor);
      renderer->AddActor(meshActor);

      renderer->GetActiveCamera()->SetPosition(1,1,1);
      renderer->ResetCamera();
      renderer->SetBackground(.2, .3, .4);

      renWin->SetSize(300,300);
      renWin->Render();

      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(DeformPointSet)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(DeformPointSet MACOSX_BUNDLE DeformPointSet.cxx )

    target_link_libraries(DeformPointSet ${VTK_LIBRARIES})

### Download and Build DeformPointSet

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

    cd DeformPointSet/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:

    ./DeformPointSet

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