# TriangleStrip

VTKExamples/Cxx/GeometricObjects/TriangleStrip

### Description

The triangle strip is a composite two-dimensional cell consisting of one or more triangles. The points defining the triangle strip need not lie in a plane. The triangle strip is defined by an ordered list of n+2 points, where n is the number of triangles. The ordering of the points is such that each set of three points defines a triangle.

Info

See this wikipedia article for an explanation.

Other Languages

See (Python), (Java), (CSharp)

### Code

TriangleStrip.cxx

    #include <vtkActor.h>
    #include <vtkCellArray.h>
    #include <vtkDataSetMapper.h>
    #include <vtkNamedColors.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>
    #include <vtkTriangleStrip.h>

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

      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(0,0,0);
      points->InsertNextPoint(0,1,0);
      points->InsertNextPoint(1,0,0);
      points->InsertNextPoint(1.5,1,0);

      vtkSmartPointer<vtkTriangleStrip> triangleStrip =
        vtkSmartPointer<vtkTriangleStrip>::New();
      triangleStrip->GetPointIds()->SetNumberOfIds(4);
      triangleStrip->GetPointIds()->SetId(0,0);
      triangleStrip->GetPointIds()->SetId(1,1);
      triangleStrip->GetPointIds()->SetId(2,2);
      triangleStrip->GetPointIds()->SetId(3,3);

      vtkSmartPointer<vtkCellArray> cells =
        vtkSmartPointer<vtkCellArray>::New();
      cells->InsertNextCell(triangleStrip);

      vtkSmartPointer<vtkPolyData> polydata =
        vtkSmartPointer<vtkPolyData>::New();
      polydata->SetPoints(points);
      polydata->SetStrips(cells);

      // Create an actor and mapper
      vtkSmartPointer<vtkDataSetMapper> mapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      mapper->SetInputData(polydata);

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

      // Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetWindowName("Triangle Strip");
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderer->AddActor(actor);
      renderer->SetBackground(colors->GetColor3d("DarkGreen").GetData());
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(TriangleStrip)

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

### Download and Build TriangleStrip

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

    cd TriangleStrip/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:

    ./TriangleStrip

WINDOWS USERS

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