# CompositePolyDataMapper

VTKExamples/Cxx/CompositeData/CompositePolyDataMapper

### Code

CompositePolyDataMapper.cxx

    #include <vtkMultiBlockDataSet.h>
    #include <vtkSphereSource.h>
    #include <vtkNew.h>
    #include <vtkCompositePolyDataMapper2.h>
    #include <vtkCompositeDataDisplayAttributes.h>
    #include <vtkActor.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>

    int main( int /* argc */, char * /* argv */ [] )
    {
      vtkNew<vtkSphereSource> sphere1;
      sphere1->SetRadius(3);
      sphere1->SetCenter(0,0,0);
      sphere1->Update();
      vtkNew<vtkSphereSource> sphere2;
      sphere2->SetRadius(2);
      sphere2->SetCenter(2,0,0);
      sphere2->Update();

      vtkNew<vtkMultiBlockDataSet> mbds;
      mbds->SetNumberOfBlocks(3);
      mbds->SetBlock(0, sphere1->GetOutput());
      // Leave block 1 NULL.  NULL blocks are valid and should be handled by
      // algorithms that process multiblock datasets.  Especially when
      // running in parallel where the blocks owned by other processes are
      // NULL in this process.
      mbds->SetBlock(2, sphere2->GetOutput());

      vtkNew<vtkCompositePolyDataMapper2> mapper;
      mapper->SetInputDataObject(mbds.GetPointer());
      vtkNew<vtkCompositeDataDisplayAttributes> cdsa;
      mapper->SetCompositeDataDisplayAttributes(cdsa.Get());

      // You can use the vtkCompositeDataDisplayAttributes to set the color,
      // opacity and visibiliy of individual blocks of the multiblock dataset.
      // Attributes are mapped by block pointers (vtkDataObject*), so these can
      // be queried by their flat index through a convenience function in the
      // attribute class (vtkCompositeDataDisplayAttributes::DataObjectFromIndex).
      // Alternatively, one can set attributes directly through the mapper using
      // flat indices.
      //
      // This sets the block at flat index 3 red
      // Note that the index is the flat index in the tree, so the whole multiblock
      // is index 0 and the blocks are flat indexes 1, 2 and 3.  This affects
      // the block returned by mbds->GetBlock(2).
      double color[] = {1, 0, 0};
      mapper->SetBlockColor(3, color);

      vtkNew<vtkActor> actor;
      actor->SetMapper(mapper.Get());

      vtkNew<vtkRenderer> renderer;
      vtkNew<vtkRenderWindow> renderWindow;
      renderWindow->AddRenderer(renderer.Get());
      vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
      renderWindowInteractor->SetRenderWindow(renderWindow.Get());

      renderer->AddActor(actor.Get());

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(CompositePolyDataMapper)

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

    add_executable(CompositePolyDataMapper MACOSX_BUNDLE CompositePolyDataMapper.cxx )

    target_link_libraries(CompositePolyDataMapper ${VTK_LIBRARIES})

### Download and Build CompositePolyDataMapper

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

    cd CompositePolyDataMapper/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:

    ./CompositePolyDataMapper

WINDOWS USERS

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