add minimal example and fix compilation

Polygon_mesh_processing/examples/Polygon_mesh_processing/CMakeLists.txt

@@ -72,6 +72,7 @@ create_single_source_cgal_program( "mesh_slicer_example.cpp")
 #create_single_source_cgal_program( "remove_degeneracies_example.cpp")
 create_single_source_cgal_program("isotropic_remeshing_example.cpp")
 create_single_source_cgal_program("isotropic_remeshing_of_patch_example.cpp")
+create_single_source_cgal_program("tangential_relaxation_example.cpp")
 create_single_source_cgal_program("surface_mesh_intersection.cpp")
 create_single_source_cgal_program("corefinement_SM.cpp")
 create_single_source_cgal_program("corefinement_consecutive_bool_op.cpp")

Polygon_mesh_processing/examples/Polygon_mesh_processing/tangential_relaxation_example.cpp

@@ -0,0 +1,36 @@
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/Surface_mesh.h>
+#include <CGAL/Polygon_mesh_processing/tangential_relaxation.h>
+#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
+
+#include <fstream>
+
+typedef CGAL::Exact_predicates_inexact_constructions_kernel   K;
+typedef CGAL::Surface_mesh<K::Point_3>                        Mesh;
+
+
+namespace PMP = CGAL::Polygon_mesh_processing;
+
+
+int main(int argc, char* argv[])
+{
+  const char* filename = (argc > 1) ? argv[1] : "data/elephant.off";
+
+  Mesh mesh;
+  if(!PMP::IO::read_polygon_mesh(filename, mesh) || !CGAL::is_triangle_mesh(mesh))
+  {
+    std::cerr << "Invalid input." << std::endl;
+    return 1;
+  }
+
+  double target_edge_length = (argc > 2) ? std::stod(std::string(argv[2])) : 0.04;
+  unsigned int nb_iter = 3;
+
+  std::cout << "Relax...";
+
+  PMP::tangential_relaxation(mesh);
+
+  std::cout << "done." << std::endl;
+
+  return 0;
+}

Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/tangential_relaxation.h

@@ -272,7 +272,7 @@ void tangential_relaxation(TriangleMesh& tm, const NamedParameters& np)
 template <class TriangleMesh>
 void tangential_relaxation(TriangleMesh& tm)
 {
-  triangle(tm, parameters::all_default());
+  tangential_relaxation(tm, parameters::all_default());
 }
 
 } } // CGAL::Polygon_mesh_processing