- decimater (incremental & mc) doesn't require normals anymore

- mod normalFlipping & normalDeviation computes normals, if mesh hasn't normals
- add 2 decimater unittest (decimating with normalFlipping and initialize all modules)

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@1049 fdac6126-5c0c-442c-9429-916003d36597

src/OpenMesh/Tools/Decimater/ModNormalFlippingT.hh

@@ -87,11 +87,21 @@ public:
   ModNormalFlippingT( MeshT &_mesh) : Base(_mesh, true)
   {
     set_max_normal_deviation( 90.0f );
+    const bool mesh_has_normals = _mesh.has_face_normals();
+    _mesh.request_face_normals();
+
+    if (!mesh_has_normals)
+    {
+      std::cerr << "Mesh has no face normals. Compute them automatically." << std::endl;
+      _mesh.update_face_normals();
+    }
   }
 
 
   ~ModNormalFlippingT()
-  { }
+  {
+    Base::mesh().release_face_normals();
+  }
 
 
 public: