# 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), (PythonicAPI), (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 <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
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.