PointInsideObject
vtk-examples/Cxx/PolyData/PointInsideObject
Description¶
This example creates a cube at the origin with side 1. Then it checks if the points are inside the cube. There is one point inside, one in the border and one outside. The answer for the first one should be yes, and for the other two, no.
Then render the cube and the points to see the result.
Question
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Code¶
PointInsideObject.cxx
#include <vtkActor.h>
#include <vtkCubeSource.h>
#include <vtkDataArray.h>
#include <vtkIntArray.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSelectEnclosedPoints.h>
#include <vtkVertexGlyphFilter.h>
int main(int, char* argv[])
{
vtkNew<vtkNamedColors> colors;
// cube centered in origin, 1cm side.
vtkNew<vtkCubeSource> cubeSource;
cubeSource->Update();
vtkPolyData* cube = cubeSource->GetOutput();
double testInside[3] = {0.0, 0.0, 0.0};
double testOutside[3] = {0.7, 0.0, 0.0};
double testBorderOutside[3] = {0.5, 0.0, 0.0};
vtkNew<vtkPoints> points;
points->InsertNextPoint(testInside);
points->InsertNextPoint(testOutside);
points->InsertNextPoint(testBorderOutside);
vtkNew<vtkPolyData> pointsPolydata;
pointsPolydata->SetPoints(points);
// Points inside test
vtkNew<vtkSelectEnclosedPoints> selectEnclosedPoints;
selectEnclosedPoints->SetInputData(pointsPolydata);
selectEnclosedPoints->SetSurfaceData(cube);
selectEnclosedPoints->Update();
for (unsigned int i = 0; i < 2; i++)
{
std::cout << "Point " << i << ": ";
if (selectEnclosedPoints->IsInside(i) == 1)
{
std::cout << "inside" << std::endl;
}
else
{
std::cout << "outside" << std::endl;
}
}
auto insideArray = dynamic_cast<vtkDataArray*>(
selectEnclosedPoints->GetOutput()->GetPointData()->GetArray(
"SelectedPoints"));
for (vtkIdType i = 0; i < insideArray->GetNumberOfTuples(); i++)
{
std::cout << "Tuple " << i << ": ";
if (insideArray->GetComponent(i, 0) == 1)
{
std::cout << "inside" << std::endl;
}
else
{
std::cout << "outside" << std::endl;
}
}
// RENDERING PART
// Cube mapper, actor
vtkNew<vtkPolyDataMapper> cubeMapper;
cubeMapper->SetInputConnection(cubeSource->GetOutputPort());
vtkNew<vtkActor> cubeActor;
cubeActor->SetMapper(cubeMapper);
cubeActor->GetProperty()->SetOpacity(0.5);
cubeActor->GetProperty()->SetColor(colors->GetColor3d("SandyBrown").GetData());
// Points mapper, actor
// First, apply vtkVertexGlyphFilter to make cells around points, vtk only
// render cells.
vtkNew<vtkVertexGlyphFilter> vertexGlyphFilter;
vertexGlyphFilter->AddInputData(pointsPolydata);
vertexGlyphFilter->Update();
vtkNew<vtkPolyDataMapper> pointsMapper;
pointsMapper->SetInputConnection(vertexGlyphFilter->GetOutputPort());
vtkNew<vtkActor> pointsActor;
pointsActor->SetMapper(pointsMapper);
pointsActor->GetProperty()->SetPointSize(5);
pointsActor->GetProperty()->SetColor(colors->GetColor3d("GreenYellow").GetData());
// Create a renderer, render window, and interactor
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("PointCellIds");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
// Add the actor to the scene
renderer->AddActor(cubeActor);
renderer->AddActor(pointsActor);
renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());
// Render and interact
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(PointInsideObject)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkFiltersGeneral
vtkFiltersModeling
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping PointInsideObject: ${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(PointInsideObject MACOSX_BUNDLE PointInsideObject.cxx )
target_link_libraries(PointInsideObject PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(PointInsideObject MACOSX_BUNDLE PointInsideObject.cxx )
target_link_libraries(PointInsideObject PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS PointInsideObject
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build PointInsideObject¶
Click here to download PointInsideObject and its CMakeLists.txt file. Once the tarball PointInsideObject.tar has been downloaded and extracted,
cd PointInsideObject/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:
./PointInsideObject
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.