StaticLocatorFindPointsWithinRadiusDemo
VTKEx/Cxx/DataStructures/StaticLocatorFindPointsWithinRadiusDemo
Description¶
This example uses vtkStaticPointLocator to find all points within a given radius. The example generates "n" spheres and finds all the points within the radius of the spheres. The input vtkPolyData's vtkPointData is set the the radius value of each sphere.
The example takes one or two arguments. The first argument specifies the input file that contains vtkPolyData. The second optional argument specifies the number of radii use. If the number is < 6, the vtkSphereSource will be displayed as concentric translucent spheres.
The image was produced with this command:
StaticLocatorFindPointsWithinRadius dragon.ply 10
To see the translucent spheres run:
StaticLocatoFindPointsWithinRadius dragon.ply
Info
See other locator demos: KDTreeFindPointsWithinRadiusDemo, OctreeFindPointsWithinRadiusDemo, PointLocatorFindPointsWithinRadiusDemo
Question
If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum
Code¶
StaticLocatorFindPointsWithinRadiusDemo.cxx
#include <vtkSmartPointer.h>
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkCellArray.h>
#include <vtkDoubleArray.h>
#include <vtkIdList.h>
#include <vtkPointData.h>
#include <vtkPointSource.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkStaticPointLocator.h>
#include <vtkLookupTable.h>
#include <vtkNamedColors.h>
// Readers
#include <vtkBYUReader.h>
#include <vtkOBJReader.h>
#include <vtkPLYReader.h>
#include <vtkPolyDataReader.h>
#include <vtkSTLReader.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkSphereSource.h>
#include <algorithm> // For transform()
#include <array>
#include <cctype> // For to_lower
#include <iostream>
#include <string> // For find_last_of()
namespace {
vtkSmartPointer<vtkPolyData> ReadPolyData(std::string const& fileName);
// Templated join which can be used on any combination
// of streams, and a container of base types.
template <typename TStream, typename TContainer, typename TSeparator>
TStream& join(TStream& stream, TContainer const& cont,
TSeparator const& separator)
{
auto sep = false;
for (auto const& p : cont)
{
if (sep)
stream << separator;
else
{
sep = true;
}
stream << p;
}
// As a convenience, return a reference to the passed stream.
return stream;
}
} // namespace
int main(int argc, char* argv[])
{
if (argc < 2)
{
std::cout << "Usage: " << argv[0] << " shark.ply [number of radii] "
<< std::endl;
return EXIT_FAILURE;
}
int numberOfRadii = 5;
if (argc > 2)
{
numberOfRadii = std::atoi(argv[2]);
}
// Read the polydata
auto polyData = ReadPolyData(argc > 1 ? argv[1] : "");
// Compute bounds and range
std::array<double, 6> bounds;
polyData->GetBounds(bounds.data());
std::cout << "Bounds: ";
join(std::cout, bounds, ", ") << std::endl;
std::array<double, 3> range;
range[0] = bounds[1] - bounds[0];
range[1] = bounds[3] - bounds[2];
range[2] = bounds[5] - bounds[4];
std::cout << "Range: ";
join(std::cout, range, ", ") << std::endl;
// double maxRange = std::max({range[0], range[1], range[2]});
double minRange = std::min({range[0], range[1], range[2]});
// Define a sphere at one edge of bounding box
auto sphereSource = vtkSmartPointer<vtkSphereSource>::New();
sphereSource->SetCenter(range[0] / 2.0 + bounds[0],
range[1] / 2.0 + bounds[2], bounds[5]);
sphereSource->SetRadius(minRange);
sphereSource->SetPhiResolution(31);
sphereSource->SetThetaResolution(31);
sphereSource->SetStartPhi(90.0);
sphereSource->Update();
// Initialize the locator
auto pointTree = vtkSmartPointer<vtkStaticPointLocator>::New();
pointTree->SetDataSet(polyData);
pointTree->BuildLocator();
// Compute the radius for each call to FindPointsWithinRadius
std::vector<double> radii;
double radiiStart = .25 * sphereSource->GetRadius();
double radiiEnd = 1.0 * sphereSource->GetRadius();
double radiiDelta = (radiiEnd - radiiStart) / (numberOfRadii - 1);
for (int r = 0; r < numberOfRadii; ++r)
{
radii.push_back(radiiStart + radiiDelta * r);
}
// Create an array to hold the scalar point data
auto scalars = vtkSmartPointer<vtkDoubleArray>::New();
scalars->SetNumberOfComponents(1);
scalars->SetNumberOfTuples(polyData->GetNumberOfPoints());
scalars->FillComponent(0, 0.0);
// Process each radii from largest to smallest
for (std::vector<double>::reverse_iterator rIter = radii.rbegin();
rIter != radii.rend(); ++rIter)
{
auto result = vtkSmartPointer<vtkIdList>::New();
pointTree->FindPointsWithinRadius(*rIter, sphereSource->GetCenter(),
result);
vtkIdType k = result->GetNumberOfIds();
std::cout << k << " points within " << *rIter << " of "
<< sphereSource->GetCenter()[0] << ", "
<< sphereSource->GetCenter()[1] << ", "
<< sphereSource->GetCenter()[2] << std::endl;
// Store the distance in the points withnin the current radius
for (vtkIdType i = 0; i < k; i++)
{
vtkIdType point_ind = result->GetId(i);
scalars->SetTuple1(point_ind, *rIter);
}
}
polyData->GetPointData()->SetScalars(scalars);
// Visualize
auto colors = vtkSmartPointer<vtkNamedColors>::New();
auto renderer = vtkSmartPointer<vtkRenderer>::New();
auto lut = vtkSmartPointer<vtkLookupTable>::New();
lut->SetHueRange(.667, 0.0);
lut->SetNumberOfTableValues(radii.size() + 1);
lut->SetRange(*radii.begin(), *radii.rbegin());
lut->Build();
// Create a transluscent sphere for each radii
if (radii.size() < 6)
{
for (std::vector<double>::reverse_iterator rIter = radii.rbegin();
rIter != radii.rend(); ++rIter)
{
auto radiiSource = vtkSmartPointer<vtkSphereSource>::New();
radiiSource->SetPhiResolution(31);
radiiSource->SetThetaResolution(31);
radiiSource->SetStartPhi(90.0);
radiiSource->SetRadius(*rIter);
radiiSource->SetCenter(range[0] / 2.0 + bounds[0],
range[1] / 2.0 + bounds[2], bounds[5]);
auto radiiMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
radiiMapper->SetInputConnection(radiiSource->GetOutputPort());
auto backProp = vtkSmartPointer<vtkProperty>::New();
backProp->SetDiffuseColor(colors->GetColor3d("LightGrey").GetData());
auto radiiActor = vtkSmartPointer<vtkActor>::New();
radiiActor->SetMapper(radiiMapper);
radiiActor->GetProperty()->SetDiffuseColor(
colors->GetColor3d("White").GetData());
radiiActor->GetProperty()->SetOpacity(.1);
radiiActor->SetBackfaceProperty(backProp);
renderer->AddActor(radiiActor);
}
}
// Display the original poly data
auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputData(polyData);
mapper->SetLookupTable(lut);
mapper->SetScalarRange(*radii.begin(), *radii.rbegin());
auto actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
actor->GetProperty()->SetDiffuseColor(
colors->GetColor3d("Crimson").GetData());
actor->GetProperty()->SetInterpolationToFlat();
auto renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->SetSize(640, 480);
renderWindow->AddRenderer(renderer);
auto renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow(renderWindow);
renderer->AddActor(actor);
renderer->SetBackground(colors->GetColor3d("BurlyWood").GetData());
renderer->UseHiddenLineRemovalOn();
renderWindow->Render();
// Pick a good view
renderer->GetActiveCamera()->Azimuth(-30);
renderer->GetActiveCamera()->Elevation(30);
renderer->GetActiveCamera()->Dolly(1.25);
renderer->ResetCameraClippingRange();
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
namespace {
vtkSmartPointer<vtkPolyData> ReadPolyData(std::string const& fileName)
{
vtkSmartPointer<vtkPolyData> polyData;
std::string extension = "";
if (fileName.find_last_of(".") != std::string::npos)
{
extension = fileName.substr(fileName.find_last_of("."));
}
// Make the extension lowercase
std::transform(extension.begin(), extension.end(), extension.begin(),
::tolower);
if (extension == ".ply")
{
auto reader = vtkSmartPointer<vtkPLYReader>::New();
reader->SetFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else if (extension == ".vtp")
{
auto reader = vtkSmartPointer<vtkXMLPolyDataReader>::New();
reader->SetFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else if (extension == ".obj")
{
auto reader = vtkSmartPointer<vtkOBJReader>::New();
reader->SetFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else if (extension == ".stl")
{
auto reader = vtkSmartPointer<vtkSTLReader>::New();
reader->SetFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else if (extension == ".vtk")
{
auto reader = vtkSmartPointer<vtkPolyDataReader>::New();
reader->SetFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else if (extension == ".g")
{
auto reader = vtkSmartPointer<vtkBYUReader>::New();
reader->SetGeometryFileName(fileName.c_str());
reader->Update();
polyData = reader->GetOutput();
}
else
{
// Return a polydata sphere if the extension is unknown.
auto source = vtkSmartPointer<vtkSphereSource>::New();
source->SetThetaResolution(20);
source->SetPhiResolution(11);
source->Update();
polyData = source->GetOutput();
}
return polyData;
}
} // namespace
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(StaticLocatorFindPointsWithinRadiusDemo)
find_package(VTK COMPONENTS
vtkvtkCommonColor
vtkvtkCommonCore
vtkvtkCommonDataModel
vtkvtkFiltersSources
vtkvtkIOGeometry
vtkvtkIOLegacy
vtkvtkIOPLY
vtkvtkIOXML
vtkvtkInteractionStyle
vtkvtkRenderingContextOpenGL2
vtkvtkRenderingCore
vtkvtkRenderingFreeType
vtkvtkRenderingGL2PSOpenGL2
vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
message("Skipping StaticLocatorFindPointsWithinRadiusDemo: ${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(StaticLocatorFindPointsWithinRadiusDemo MACOSX_BUNDLE StaticLocatorFindPointsWithinRadiusDemo.cxx )
target_link_libraries(StaticLocatorFindPointsWithinRadiusDemo PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(StaticLocatorFindPointsWithinRadiusDemo MACOSX_BUNDLE StaticLocatorFindPointsWithinRadiusDemo.cxx )
target_link_libraries(StaticLocatorFindPointsWithinRadiusDemo PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS StaticLocatorFindPointsWithinRadiusDemo
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build StaticLocatorFindPointsWithinRadiusDemo¶
Click here to download StaticLocatorFindPointsWithinRadiusDemo and its CMakeLists.txt file. Once the tarball StaticLocatorFindPointsWithinRadiusDemo.tar has been downloaded and extracted,
cd StaticLocatorFindPointsWithinRadiusDemo/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:
./StaticLocatorFindPointsWithinRadiusDemo
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.