ConvexHullShrinkWrap
vtk-examples/Cxx/PolyData/ConvexHullShrinkWrap
Description¶
This example creates a point cloud, and a sphere larger than the point cloud which fully contains the cloud. It then "shrink wraps" the sphere onto the points. This produces an approximation of a convex hull.
Other languages
See (Java)
Question
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Code¶
ConvexHullShrinkWrap.cxx
#include <vtkActor.h>
#include <vtkDataSetMapper.h>
#include <vtkGlyph3D.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointSource.h>
#include <vtkPolyData.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmoothPolyDataFilter.h>
#include <vtkSphereSource.h>
int main(int, char*[])
{
vtkNew<vtkNamedColors> namedColors;
vtkNew<vtkSphereSource> sphereSource;
sphereSource->SetRadius(10);
sphereSource->SetPhiResolution(50);
sphereSource->SetThetaResolution(50);
vtkNew<vtkPointSource> pointSource;
pointSource->SetNumberOfPoints(60);
pointSource->SetRadius(2);
vtkNew<vtkSmoothPolyDataFilter> smoothFilter;
smoothFilter->SetInputConnection(0, sphereSource->GetOutputPort());
smoothFilter->SetInputConnection(1, pointSource->GetOutputPort());
vtkNew<vtkSphereSource> glyphSource;
glyphSource->SetRadius(.04);
vtkNew<vtkGlyph3D> glyph3D;
glyph3D->SetInputConnection(pointSource->GetOutputPort());
glyph3D->SetSourceConnection(glyphSource->GetOutputPort());
glyph3D->ScalingOff();
vtkNew<vtkDataSetMapper> glyph3DMapper;
glyph3DMapper->SetInputConnection(glyph3D->GetOutputPort());
glyph3DMapper->ScalarVisibilityOff();
vtkNew<vtkActor> glyph3DActor;
glyph3DActor->SetMapper(glyph3DMapper);
glyph3DActor->GetProperty()->SetColor(
namedColors->GetColor3d("Banana").GetData());
vtkNew<vtkDataSetMapper> mapper;
mapper->SetInputConnection(smoothFilter->GetOutputPort());
mapper->ScalarVisibilityOff();
// Create an actor for the surface
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetDiffuseColor(
namedColors->GetColor3d("Tomato").GetData());
actor->GetProperty()->SetEdgeColor(
namedColors->GetColor3d("IvoryBlack").GetData());
actor->GetProperty()->SetOpacity(1.0);
actor->GetProperty()->EdgeVisibilityOff();
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("ConvexHullShrinkWrap");
vtkNew<vtkRenderWindowInteractor> interactor;
interactor->SetRenderWindow(renderWindow);
renderer->AddActor(actor);
renderer->AddActor(glyph3DActor);
renderer->SetBackground(namedColors->GetColor3d("SlateGray").GetData());
renderWindow->Render();
interactor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(ConvexHullShrinkWrap)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkFiltersCore
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping ConvexHullShrinkWrap: ${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(ConvexHullShrinkWrap MACOSX_BUNDLE ConvexHullShrinkWrap.cxx )
target_link_libraries(ConvexHullShrinkWrap PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(ConvexHullShrinkWrap MACOSX_BUNDLE ConvexHullShrinkWrap.cxx )
target_link_libraries(ConvexHullShrinkWrap PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS ConvexHullShrinkWrap
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build ConvexHullShrinkWrap¶
Click here to download ConvexHullShrinkWrap and its CMakeLists.txt file. Once the tarball ConvexHullShrinkWrap.tar has been downloaded and extracted,
cd ConvexHullShrinkWrap/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:
./ConvexHullShrinkWrap
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.