# DelaunayMesh

Repository source: DelaunayMesh

### Description¶

This is two-dimensional Delaunay triangulation of a random set of points. Points and edges are shown highlighted with spheres and tubes.

Other languages

See (Python), (PythonicAPI), (Java)

Question

### Code¶

DelaunayMesh.cxx

/*
This code is based on the VTK file: Examples/Modelling/Tcl/DelMesh.py.

This example demonstrates how to use 2D Delaunay triangulation.
We create a fancy image of a 2D Delaunay triangulation. Points are
randomly generated.
*/

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkDelaunay2D.h>
#include <vtkExtractEdges.h>
#include <vtkGlyph3D.h>
#include <vtkMinimalStandardRandomSequence.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>
#include <vtkTubeFilter.h>

// Note that:
// vtkExtractEdges moved from vtkFiltersExtraction to vtkFiltersCore in
// VTK commit d9981b9aeb93b42d1371c6e295d76bfdc18430bd

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

// Generate some "random" points.
vtkNew<vtkPoints> points;
vtkNew<vtkMinimalStandardRandomSequence> randomSequence;
randomSequence->SetSeed(1);
for (auto i = 0; i < 50; ++i)
{
double p1;
double p2;
p1 = randomSequence->GetValue();
randomSequence->Next();
p2 = randomSequence->GetValue();
randomSequence->Next();
points->InsertPoint(i, p1, p2, 0.0);
}
// Create a polydata with the points we just created.
vtkNew<vtkPolyData> profile;
profile->SetPoints(points);

// Perform a 2D Delaunay triangulation on them.
vtkNew<vtkDelaunay2D> delny;
delny->SetInputData(profile);
delny->SetTolerance(0.001);
vtkNew<vtkPolyDataMapper> mapMesh;
mapMesh->SetInputConnection(delny->GetOutputPort());
vtkNew<vtkActor> meshActor;
meshActor->SetMapper(mapMesh);
meshActor->GetProperty()->SetColor(
colors->GetColor3d("MidnightBlue").GetData());

// We will now create a nice looking mesh by wrapping the edges in tubes,
// and putting fat spheres at the points.
vtkNew<vtkExtractEdges> extract;
extract->SetInputConnection(delny->GetOutputPort());
vtkNew<vtkTubeFilter> tubes;
tubes->SetInputConnection(extract->GetOutputPort());
tubes->SetNumberOfSides(6);
vtkNew<vtkPolyDataMapper> mapEdges;
mapEdges->SetInputConnection(tubes->GetOutputPort());
vtkNew<vtkActor> edgeActor;
edgeActor->SetMapper(mapEdges);
edgeActor->GetProperty()->SetColor(colors->GetColor3d("peacock").GetData());
edgeActor->GetProperty()->SetSpecularColor(1, 1, 1);
edgeActor->GetProperty()->SetSpecular(0.3);
edgeActor->GetProperty()->SetSpecularPower(20);
edgeActor->GetProperty()->SetAmbient(0.2);
edgeActor->GetProperty()->SetDiffuse(0.8);

vtkNew<vtkSphereSource> ball;
ball->SetThetaResolution(12);
ball->SetPhiResolution(12);
vtkNew<vtkGlyph3D> balls;
balls->SetInputConnection(delny->GetOutputPort());
balls->SetSourceConnection(ball->GetOutputPort());
vtkNew<vtkPolyDataMapper> mapBalls;
mapBalls->SetInputConnection(balls->GetOutputPort());
vtkNew<vtkActor> ballActor;
ballActor->SetMapper(mapBalls);
ballActor->GetProperty()->SetColor(colors->GetColor3d("hot_pink").GetData());
ballActor->GetProperty()->SetSpecularColor(1, 1, 1);
ballActor->GetProperty()->SetSpecular(0.3);
ballActor->GetProperty()->SetSpecularPower(20);
ballActor->GetProperty()->SetAmbient(0.2);
ballActor->GetProperty()->SetDiffuse(0.8);

// Create the rendering window, renderer, and interactive renderer.
vtkNew<vtkRenderer> ren;
vtkNew<vtkRenderWindow> renWin;
vtkNew<vtkRenderWindowInteractor> iren;
iren->SetRenderWindow(renWin);

// Add the actors to the renderer, set the background and size.
ren->SetBackground(colors->GetColor3d("AliceBlue").GetData());
renWin->SetSize(512, 512);
renWin->SetWindowName("DelaunayMesh");

ren->ResetCamera();
ren->GetActiveCamera()->Zoom(1.3);

// Interact with the data.
iren->Initialize();
renWin->Render();
iren->Start();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(DelaunayMesh)

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

if (NOT VTK_FOUND)
message(FATAL_ERROR "DelaunayMesh: 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.")
target_link_libraries(DelaunayMesh PRIVATE ${VTK_LIBRARIES} ) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS DelaunayMesh MODULES${VTK_LIBRARIES}
)


cd DelaunayMesh/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:

./DelaunayMesh


WINDOWS USERS

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