From 8a155b4f5d9ae8e52db139ae674221cedca4aa7c Mon Sep 17 00:00:00 2001
From: Maxime Gimeno <maxime.gimeno@gmail.com>
Date: Mon, 8 Feb 2016 15:29:30 +0100
Subject: [PATCH] The scene performs a check on the item to insure it is able
 to display its primitive IDs.

---
 Polyhedron/demo/Polyhedron/Scene.cpp              | 15 +++++++++++++--
 Three/include/CGAL/Three/Scene_item.h             |  2 +-
 .../CGAL/Three/Scene_item_print_interface.h       |  2 +-
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/Polyhedron/demo/Polyhedron/Scene.cpp b/Polyhedron/demo/Polyhedron/Scene.cpp
index e56bec4bb38..965b852ff56 100644
--- a/Polyhedron/demo/Polyhedron/Scene.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene.cpp
@@ -5,6 +5,7 @@
 #include "config.h"
 #include "Scene.h"
 #include  <CGAL/Three/Scene_item.h>
+#include <CGAL/Three/Scene_item_print_interface.h>
 
 #include <QObject>
 #include <QMetaObject>
@@ -1141,13 +1142,23 @@ void Scene::printPrimitiveId(QPoint point, CGAL::Three::Viewer_interface* viewer
 {
   Scene_item *it = item(mainSelectionIndex());
   if(it)
-    it->printPrimitiveId(point, viewer);
+  {
+    //Only call printPrimitiveId if the item is a Scene_item_print_interface
+    Scene_item_print_interface* item= dynamic_cast<Scene_item_print_interface*>(it);
+    if(item)
+      item->printPrimitiveId(point, viewer);
+  }
 }
 void Scene::printPrimitiveIds(CGAL::Three::Viewer_interface* viewer)
 {
   Scene_item *it = item(mainSelectionIndex());
   if(it)
-    it->printPrimitiveIds(viewer);
+  {
+    //Only call printPrimitiveIds if the item is a Scene_item_print_interface
+    Scene_item_print_interface* item= dynamic_cast<Scene_item_print_interface*>(it);
+    if(item)
+      item->printPrimitiveIds(viewer);
+  }
 }
 bool Scene::testDisplayId(double x, double y, double z, CGAL::Three::Viewer_interface* viewer)
 {
diff --git a/Three/include/CGAL/Three/Scene_item.h b/Three/include/CGAL/Three/Scene_item.h
index aceea6b8479..c5a1a9bcc78 100644
--- a/Three/include/CGAL/Three/Scene_item.h
+++ b/Three/include/CGAL/Three/Scene_item.h
@@ -47,7 +47,7 @@ namespace Three {
 class Scene_group_item;
 class Viewer_interface;
 //! This class represents an object in the OpenGL scene
-class SCENE_ITEM_EXPORT Scene_item : public QObject, CGAL::Three::Scene_item_print_interface {
+class SCENE_ITEM_EXPORT Scene_item : public QObject, public CGAL::Three::Scene_item_print_interface {
   Q_OBJECT
   Q_PROPERTY(QColor color READ color WRITE setColor)
   Q_PROPERTY(QString name READ name WRITE setName)
diff --git a/Three/include/CGAL/Three/Scene_item_print_interface.h b/Three/include/CGAL/Three/Scene_item_print_interface.h
index c2020421fc6..9d283d76be9 100644
--- a/Three/include/CGAL/Three/Scene_item_print_interface.h
+++ b/Three/include/CGAL/Three/Scene_item_print_interface.h
@@ -26,7 +26,7 @@ namespace Three {
   class Viewer_interface;
 
 
-//! Base class to allow an item to print ts primitive.
+//! Base class to allow an item to print its primitive IDs.
 class Scene_item_print_interface {
 public:
   virtual ~Scene_item_print_interface(){}