At least allow to write polyhedral surfaces into .obj files

Polyhedron/demo/Polyhedron/Plugins/IO/OFF_io_plugin.cpp

@@ -155,9 +155,16 @@ bool Polyhedron_demo_off_plugin::save(const CGAL::Three::Scene_item* item, QFile
 
   std::ofstream out(fileinfo.filePath().toUtf8());
   out.precision (std::numeric_limits<double>::digits10 + 2);
-  return (poly_item && poly_item->save(out)) || 
-    (soup_item && soup_item->save(out)) ||
-    (points_item && points_item->write_off_point_set(out));
+
+  if(fileinfo.suffix().toLower() == "off"){
+    return (poly_item && poly_item->save(out)) || 
+      (soup_item && soup_item->save(out)) ||
+      (points_item && points_item->write_off_point_set(out));
+  }
+  if(fileinfo.suffix().toLower() == "obj"){
+    return (poly_item && poly_item->save_obj(out));
+  }
+  return false;
 }
 
 #include "OFF_io_plugin.moc"

Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp

@@ -3,6 +3,8 @@
 #include <CGAL/AABB_intersections.h>
 #include "Kernel_type.h"
 #include <CGAL/IO/Polyhedron_iostream.h>
+#include <CGAL/IO/File_writer_wavefront.h>
+#include <CGAL/IO/generic_copy_OFF.h>
 
 #include <CGAL/AABB_tree.h>
 #include <CGAL/AABB_traits.h>
@@ -730,6 +732,15 @@ Scene_polyhedron_item::save(std::ostream& out) const
     return (bool) out;
 }
 
+bool
+Scene_polyhedron_item::save_obj(std::ostream& out) const
+{
+  CGAL::File_writer_wavefront  writer;
+  CGAL::generic_print_polyhedron(out, *poly, writer);
+  return out.good();
+}
+
+
 QString
 Scene_polyhedron_item::toolTip() const
 {

Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h

@@ -58,6 +58,7 @@ public:
     bool load(std::istream& in);
     bool load_obj(std::istream& in);
     bool save(std::ostream& out) const;
+    bool save_obj(std::ostream& out) const;
 
     // Function for displaying meta-data of the item
     virtual QString toolTip() const;