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.