CGAL users discussion list

[Eric Lombardi <>]

Hello,

I'm looking for a way to do a radius search with Surface_mesh that 
returns a list of vertex descriptors.

The following example do what I want with Polyhedron_3:


"https://github.com/CGAL/cgal/blob/releases/CGAL-4.14.2/Spatial_searching/examples/Spatial_searching/searching_polyhedron_vertices_with_fuzzy_sphere.cpp";

I tried to change this example to make it work with Surface_mesh. The 
code compiles, but there is a runtime error:

  terminate called after throwing an instance of
  'CGAL::Assertion_exception'
    what():  CGAL ERROR: assertion violation!
  Expr: parray_ != NULL
  File: ~/CGAL-4.14.2/include/CGAL/Surface_mesh/Properties.h
  Line: 576

The same error occurs with CGAL-4.14.2 and CGAL-5.0.1.


The source code is attached (radius_search.cpp). The "#if" at line 16 
toggles between Polyhedron_3 and Surface_mesh.


What is wrong with Surface_mesh with this code ?


Regards,

--

Eric Lombardi

==============================================================
LIRIS, UMR 5205
Laboratoire d'InfoRmatique en Image et Systèmes d'information
Université Claude Bernard Lyon 1, bâtiment Nautibus
43 boulevard du 11 novembre 1918, 69622 Villeurbanne cedex

#include <CGAL/Cartesian.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/Surface_mesh.h>

#include <CGAL/Search_traits_3.h>
#include <CGAL/Search_traits_adapter.h>
#include <CGAL/Kd_tree.h>
#include <CGAL/Fuzzy_sphere.h>

#include <fstream>


typedef CGAL::Cartesian<double> Kernel;
typedef Kernel::Point_3 Point_3;
#if 0
typedef CGAL::Polyhedron_3<Kernel> Mesh;
#else
typedef CGAL::Surface_mesh<Point_3> Mesh;
#endif
typedef boost::graph_traits<Mesh>::vertex_descriptor     vertex_descriptor;
typedef boost::property_map<Mesh,
                            CGAL::vertex_point_t>::type  Vertex_point_pmap;

typedef CGAL::Search_traits_3<Kernel>                    Traits_base;
typedef CGAL::Search_traits_adapter<vertex_descriptor,
                                    Vertex_point_pmap,
                                    Traits_base>         Traits;

typedef CGAL::Kd_tree<Traits>                            Tree;
typedef Tree::Splitter                                   Splitter;


int main(int argc, char* argv[])
{
  Mesh mesh;
  std::ifstream in((argc>1)?argv[1]:"../tripod.off");
  in  >> mesh;
  Vertex_point_pmap vppmap = get(CGAL::vertex_point, mesh);

  // display number of vertices and 2 first points
  std::cout << "number of points = " << num_vertices(mesh) << std::endl;
  auto it = vertices(mesh).first;
  auto it_end = vertices(mesh).second;
  for(int i = 0; it != it_end && i < 2; i++, ++it)
  {
    Point_3 p = get(vppmap, *it);
    std::cout << "p = " << p << std::endl;
  }

  // Insert number_of_data_points in the tree
  Tree tree(vertices(mesh).begin(),
            vertices(mesh).end(),
            Splitter(),
            Traits(vppmap)
  );

  Point_3 query(0.0, 0.0, 0.0);
  double radius = 0.5;
  double epsilon = 0.01;

  // search vertices
  CGAL::Fuzzy_sphere<Traits> fz(query, radius, epsilon);
  
  //collect vertices that are inside the sphere
  std::list<vertex_descriptor> result;
  tree.search(std::back_inserter(result), fz);
  std::cout << "There are " << result.size() << " vertices inside the fuzzy sphere\n";

  return 0;
}

Attachment: tripod.off
Description: model/geomview-off

# Created by the script cgal_create_CMakeLists
# This is the CMake script for compiling a set of CGAL applications.

project( radius_search )


cmake_minimum_required(VERSION 2.8.11)

# CGAL and its components
find_package( CGAL QUIET COMPONENTS  )

if ( NOT CGAL_FOUND )

  message(STATUS "This project requires the CGAL library, and will not be 
compiled.")
  return()  

endif()


# Boost and its components
find_package( Boost REQUIRED )

if ( NOT Boost_FOUND )

  message(STATUS "This project requires the Boost library, and will not be 
compiled.")

  return()  

endif()

# include for local directory

# include for local package

# ############################

add_executable( radius_search  radius_search.cpp )
target_link_libraries(radius_search ${CGAL_LIBRARIES} 
${CGAL_3RD_PARTY_LIBRARIES} )