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# SingleSplat

VTKEx/Cxx/VisualizationAlgorithms/SingleSplat

### Description

This example shows a single elliptical splat.

Info

See Figure 9-38a in Chapter 9 The VTK Textbook.

Other languages

See (Python)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

### Code

SingleSplat.cxx

    #include <vtkActor.h>
    #include <vtkCellArray.h>
    #include <vtkConeSource.h>
    #include <vtkContourFilter.h>
    #include <vtkDoubleArray.h>
    #include <vtkGaussianSplatter.h>
    #include <vtkNamedColors.h>
    #include <vtkOutlineFilter.h>
    #include <vtkPointData.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>

    int main( int, char *[] )
    {
      double x[3], n[3];

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

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

      // Create single splat point
      vtkSmartPointer<vtkPoints> pts =
        vtkSmartPointer<vtkPoints>::New();
      vtkSmartPointer<vtkCellArray> verts =
        vtkSmartPointer<vtkCellArray>::New();
      vtkSmartPointer<vtkDoubleArray> norms =
        vtkSmartPointer<vtkDoubleArray>::New();
      vtkSmartPointer<vtkDoubleArray> scalars =
        vtkSmartPointer<vtkDoubleArray>::New();

      x[0] = x[1] = x[2] = 0.0;
      pts->InsertNextPoint(x);
      norms->SetNumberOfTuples(1);
      norms->SetNumberOfComponents(3);
      n[0] = 0.707; n[1] = 0.707; n[2] = 0.0;
      norms->InsertTuple(0, n);
      scalars->SetNumberOfTuples(1);
      scalars->SetNumberOfComponents(1);
      scalars->InsertTuple1(0, 1.0);

      verts->InsertNextCell(1);
      verts->InsertCellPoint(0);

      vtkSmartPointer<vtkPolyData> pData =
        vtkSmartPointer<vtkPolyData>::New();
      pData->SetPoints(pts);
      pData->SetVerts(verts);
      pData->GetPointData()->SetNormals(norms);
      pData->GetPointData()->SetScalars(scalars);

      // Splat point and generate isosurface
      vtkSmartPointer<vtkGaussianSplatter> splat =
        vtkSmartPointer<vtkGaussianSplatter>::New();
      splat->SetInputData(pData);
      splat->SetModelBounds(-1.0,1.0, -1.0,1.0, -1.0,1.0);
      splat->SetSampleDimensions(75,75,75);
      splat->SetRadius(0.5);
      splat->SetEccentricity(5.0);
      splat->SetExponentFactor(-3.25);
      vtkSmartPointer<vtkContourFilter> contour =
        vtkSmartPointer<vtkContourFilter>::New();
      contour->SetInputConnection(splat->GetOutputPort());
      contour->SetValue(0, 0.9);
      vtkSmartPointer<vtkPolyDataMapper> splatMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      splatMapper->SetInputConnection(contour->GetOutputPort());
      vtkSmartPointer<vtkActor> splatActor =
        vtkSmartPointer<vtkActor>::New();
      splatActor->SetMapper(splatMapper);

      // Create outline
      vtkSmartPointer<vtkOutlineFilter> outline =
        vtkSmartPointer<vtkOutlineFilter>::New();
      outline->SetInputConnection(splat->GetOutputPort());
      vtkSmartPointer<vtkPolyDataMapper> outlineMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      outlineMapper->SetInputConnection(outline->GetOutputPort());
      vtkSmartPointer<vtkActor> outlineActor =
        vtkSmartPointer<vtkActor>::New();
      outlineActor->SetMapper(outlineMapper);
      outlineActor->GetProperty()->SetColor(colors->GetColor3d("Brown").GetData());

      // Create cone to indicate direction
      vtkSmartPointer<vtkConeSource> cone =
        vtkSmartPointer<vtkConeSource>::New();
      cone->SetResolution(24);
      vtkSmartPointer<vtkPolyDataMapper> coneMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      coneMapper->SetInputConnection(cone->GetOutputPort());
      vtkSmartPointer<vtkActor> coneActor =
        vtkSmartPointer<vtkActor>::New();
      coneActor->SetMapper(coneMapper);
      coneActor->SetScale(0.75,0.75,0.75);
      coneActor->RotateZ(45.0);
      coneActor->AddPosition(0.50,0.50,0.0);
      coneActor->GetProperty()->SetColor(colors->GetColor3d("DeepPink").GetData());
    //
    // Rendering stuff
    //
      aren->SetBackground(colors->GetColor3d("Beige").GetData());
      aren->AddActor(splatActor);
      aren->AddActor(outlineActor);
      aren->AddActor(coneActor);

      renWin->SetSize(640, 480);
      renWin->Render();

      // interact with data
      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(SingleSplat)

    find_package(VTK COMPONENTS
      vtkvtkCommonColor
      vtkvtkCommonCore
      vtkvtkCommonDataModel
      vtkvtkFiltersCore
      vtkvtkFiltersModeling
      vtkvtkFiltersSources
      vtkvtkImagingHybrid
      vtkvtkInteractionStyle
      vtkvtkRenderingContextOpenGL2
      vtkvtkRenderingCore
      vtkvtkRenderingFreeType
      vtkvtkRenderingGL2PSOpenGL2
      vtkvtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping SingleSplat: ${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(SingleSplat MACOSX_BUNDLE SingleSplat.cxx )
      target_link_libraries(SingleSplat PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(SingleSplat MACOSX_BUNDLE SingleSplat.cxx )
      target_link_libraries(SingleSplat PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS SingleSplat
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build SingleSplat

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

    cd SingleSplat/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:

    ./SingleSplat

WINDOWS USERS

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