Add check that it faces are triangles

Polygon_mesh_processing/examples/Polygon_mesh_processing/sample_example.cpp

@@ -34,7 +34,9 @@ int main(int argc, char* argv[])
 
   std::vector<Point> points;
 
-  PMP::sample_triangle_mesh(mesh, std::back_inserter(points), CGAL::parameters::number_of_points_per_face(points_per_face));
+  PMP::sample_triangle_mesh(mesh,
+                            std::back_inserter(points),
+                            CGAL::parameters::number_of_points_per_face(points_per_face));
 
   std::cout.precision(17);
   for(const Point& p : points){
@@ -43,8 +45,7 @@ int main(int argc, char* argv[])
 
   Point_set point_set;
   PMP::sample_triangle_mesh(mesh,
-                            point_set.point_back_inserter(),
-                            CGAL::parameters::point_map(point_set.point_push_map()));
+                            point_set.point_back_inserter());
 
   std::cout << point_set.number_of_points() << std::endl;
   return 0;

Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/distance.h

@@ -747,7 +747,7 @@ struct Triangle_structure_sampler_for_triangle_soup
  * @tparam TriangleMesh a model of the concepts `EdgeListGraph` and `FaceListGraph`
  * @tparam PointOutputIterator a model of `OutputIterator`
  *  holding objects of the same point type as
- *  the value type of the point type associated to the mesh `tm`, i.e. the value type of the vertex
+ *  the value type of the point type associated to the mesh `tm`, i.e., the value type of the vertex
  *  point map property map, if provided, or the value type of the internal point property map otherwise
  * @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
  *
@@ -1570,7 +1570,7 @@ bounded_error_squared_Hausdorff_distance_impl(const TriangleMesh1& tm1,
     candidate_triangles.pop();
 
     // Only process the triangle if it can contribute to the Hausdorff distance,
-    // i.e. if its upper bound is higher than the currently known best lower bound
+    // i.e., if its upper bound is higher than the currently known best lower bound
     // and the difference between the bounds to be obtained is larger than the
     // user-given error.
     const auto& triangle_bounds = triangle_and_bounds.bounds;

Polyhedron/demo/Polyhedron/Plugins/Operations_on_polyhedra/Point_set_from_sampling_plugin.cpp

@@ -1,3 +1,5 @@
+
+#include <CGAL/Three/Three.h>
 #include <QApplication>
 #include <QAction>
 #include <QList>
@@ -14,6 +16,7 @@
 #include "Messages_interface.h"
 
 #include <CGAL/Polygon_mesh_processing/distance.h>
+#include <CGAL/boost/graph/helpers.h>
 
 using namespace CGAL::Three;
 class Polyhedron_demo_point_set_from_sampling_plugin :
@@ -52,7 +55,7 @@ void Polyhedron_demo_point_set_from_sampling_plugin::init(QMainWindow* mainWindo
                                                           Messages_interface*)
 {
   scene = scene_interface;
-  actionPointSetFromSampling = new QAction(tr("&Create Point Set from Sampling"), mainWindow);
+  actionPointSetFromSampling = new QAction(tr("Create Point Set from Sampling"), mainWindow);
   actionPointSetFromSampling->setObjectName("actionPointSetFromSampling");
   connect(actionPointSetFromSampling, SIGNAL(triggered()),
           this, SLOT(createPointSet()));
@@ -75,18 +78,24 @@ void Polyhedron_demo_point_set_from_sampling_plugin::createPointSet()
   if (points){
     points->setColor(Qt::blue);
   }else{
+    QApplication::restoreOverrideCursor();
     return;
   }
   Scene_surface_mesh_item* sm_item =
     qobject_cast<Scene_surface_mesh_item*>(scene->item(index));
 
   if (sm_item){
+    if(! CGAL::is_triangle_mesh(*sm_item->polyhedron())){
+      CGAL::Three::Three::error(QString("The mesh must have triangle faces"));
+      QApplication::restoreOverrideCursor();
+      return;
+    }
     int nf = num_faces(*sm_item->polyhedron());
 
     bool ok;
     int nb = 0;
     nb = QInputDialog::getInt(QApplication::activeWindow(), "Sampling",
-                              "Enter number of sample points:",
+                              "Number of sample points:",
                               nf , 0, (std::numeric_limits<int>::max)(), 1, &ok);
 
     points->setName(QString("%1 (sampled)").arg(sm_item->name()));
@@ -95,9 +104,9 @@ void Polyhedron_demo_point_set_from_sampling_plugin::createPointSet()
       CGAL::Polygon_mesh_processing::sample_triangle_mesh(*sm_item->polyhedron(),
                                                           points->point_set()->point_back_inserter(),
                                                           CGAL::parameters::number_of_points_on_faces(nb)
-                                                          .point_map(points->point_set()->point_push_map())
                                                           .do_sample_vertices(false)
                                                           .do_sample_edges(false));
+      scene->addItem(points);
     }
   }
 
@@ -107,10 +116,18 @@ void Polyhedron_demo_point_set_from_sampling_plugin::createPointSet()
   if (soup_item){
     int nf = soup_item->polygons().size();
 
+    for(const auto& f : soup_item->polygons()){
+      if(f.size() != 3){
+        CGAL::Three::Three::error(QString("The polygons must be triangles"));
+        QApplication::restoreOverrideCursor();
+        return;
+      }
+    }
+
     bool ok;
     int nb = 0;
     nb = QInputDialog::getInt(QApplication::activeWindow(), "Sampling",
-                              "Enter number of sample points:",
+                              "Number of sample points:",
                               nf , 0, (std::numeric_limits<int>::max)(), 1, &ok);
     points->setName(QString("%1 (sampled)").arg(soup_item->name()));
     if( ok & (nb > 0)){
@@ -119,13 +136,13 @@ void Polyhedron_demo_point_set_from_sampling_plugin::createPointSet()
                                                           soup_item->polygons(),
                                                           points->point_set()->point_back_inserter(),
                                                           CGAL::parameters::number_of_points_on_faces(nb)
-                                                          .point_map(points->point_set()->point_push_map())
                                                           .do_sample_vertices(false)
                                                           .do_sample_edges(false));
+      scene->addItem(points);
     }
   }
 
-  scene->addItem(points);
+
   QApplication::restoreOverrideCursor();
 }