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)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

TriangleStrip.cxx

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

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkPoints> points;
  points->InsertNextPoint(0, 0, 0);
  points->InsertNextPoint(0, 1, 0);
  points->InsertNextPoint(1, 0, 0);
  points->InsertNextPoint(1.5, 1, 0);

  vtkNew<vtkTriangleStrip> triangleStrip;
  triangleStrip->GetPointIds()->SetNumberOfIds(4);
  triangleStrip->GetPointIds()->SetId(0, 0);
  triangleStrip->GetPointIds()->SetId(1, 1);
  triangleStrip->GetPointIds()->SetId(2, 2);
  triangleStrip->GetPointIds()->SetId(3, 3);

  vtkNew<vtkCellArray> cells;
  cells->InsertNextCell(triangleStrip);

  vtkNew<vtkPolyData> polydata;
  polydata->SetPoints(points);
  polydata->SetStrips(cells);

  // Create an actor and mapper
  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputData(polydata);

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("PeachPuff").GetData());
  actor->GetProperty()->SetRepresentationToWireframe();

  // Create a renderer, render window, and interactor
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetWindowName("TriangleStrip");
  renderWindow->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  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 3.12 FATAL_ERROR)

project(TriangleStrip)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "TriangleStrip: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
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}
)

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.