# ConvexPointSet

vtk-examples/Cxx/GeometricObjects/ConvexPointSet

### Description¶

vtkConvexPointSet object represents a 3D cell defined by a convex set of points. An example of such a cell is an octant (from an octree).

vtkConvexPointSet uses the ordered triangulations approach (vtkOrderedTriangulator) to create triangulations guaranteed to be compatible across shared faces.

Other languages

See (Python), (Java)

Question

### Code¶

ConvexPointSet.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkConvexPointSet.h>
#include <vtkDataSetMapper.h>
#include <vtkGlyph3DMapper.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkShrinkFilter.h>
#include <vtkSphereSource.h>
#include <vtkUnstructuredGrid.h>

int main(int, char*[])
{
vtkNew<vtkConvexPointSet> cps;
vtkNew<vtkPoints> points;
points->InsertNextPoint(0, 0, 0);
points->InsertNextPoint(1, 0, 0);
points->InsertNextPoint(1, 1, 0);
points->InsertNextPoint(0, 1, 0);
points->InsertNextPoint(0, 0, 1);
points->InsertNextPoint(1, 0, 1);
points->InsertNextPoint(1, 1, 1);
points->InsertNextPoint(0, 1, 1);
points->InsertNextPoint(0.5, 0, 0);
points->InsertNextPoint(1, 0.5, 0);
points->InsertNextPoint(0.5, 1, 0);
points->InsertNextPoint(0, 0.5, 0);
points->InsertNextPoint(0.5, 0.5, 0);

for (int i = 0; i < 13; ++i)
{
cps->GetPointIds()->InsertId(i, i);
}

vtkNew<vtkUnstructuredGrid> ug;
ug->Allocate(1, 1);
ug->InsertNextCell(cps->GetCellType(), cps->GetPointIds());
ug->SetPoints(points);

vtkNew<vtkNamedColors> colors;

vtkNew<vtkDataSetMapper> mapper;
mapper->SetInputData(ug);

vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());
actor->GetProperty()->SetLineWidth(3);
actor->GetProperty()->EdgeVisibilityOn();

// Glyph the points
vtkNew<vtkSphereSource> sphere;
sphere->SetPhiResolution(21);
sphere->SetThetaResolution(21);

// Create a polydata to store everything in
vtkNew<vtkPolyData> polyData;
polyData->SetPoints(points);

vtkNew<vtkGlyph3DMapper> pointMapper;
pointMapper->SetInputData(polyData);
pointMapper->SetSourceConnection(sphere->GetOutputPort());

vtkNew<vtkActor> pointActor;
pointActor->SetMapper(pointMapper);
pointActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

// Create a renderer, render window, and interactor
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetWindowName("ConvexPointSet");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);

// Add the actors to the scene
renderer->SetBackground(colors->GetColor3d("Silver").GetData());

renderer->ResetCamera();
renderer->GetActiveCamera()->Azimuth(210);
renderer->GetActiveCamera()->Elevation(30);
renderer->ResetCameraClippingRange();

// Render and interact
renderWindow->SetSize(640, 480);
renderWindow->Render();
renderWindowInteractor->Start();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ConvexPointSet)

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

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


cd ConvexPointSet/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:

./ConvexPointSet


WINDOWS USERS

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