added RequireTriangularMesh guard and corresponding exception

vcg/complex/base.h

@@ -610,6 +610,8 @@ template <class MeshType> void RequireCompactness    (MeshType &m) {
   if(m.face.size()!=size_t(m.fn)) throw vcg::MissingCompactnessException("Face Vector Contains deleted elements");
 }
 
+template <class MeshType> void RequireTriangularMesh (MeshType &m) { if(typename MeshType::FaceType::HasPolyInfo()) throw vcg::MissingTriangularRequirementException("");}
+
 template <class MeshType> void RequireVFAdjacency    (MeshType &m) { if(!tri::HasVFAdjacency   (m)) throw vcg::MissingComponentException("VFAdjacency"); }
 template <class MeshType> void RequireVEAdjacency    (MeshType &m) { if(!tri::HasVEAdjacency   (m)) throw vcg::MissingComponentException("VEAdjacency"); }
 template <class MeshType> void RequireFFAdjacency    (MeshType &m) { if(!tri::HasFFAdjacency   (m)) throw vcg::MissingComponentException("FFAdjacency"); }

vcg/complex/exception.h

@@ -38,6 +38,7 @@ public:
       return buf;
     }
 };
+
 class MissingCompactnessException : public std::runtime_error
 {
 public:
@@ -51,6 +52,21 @@ public:
       return buf;
     }
 };
+
+class MissingTriangularRequirementException : public std::runtime_error
+{
+public:
+  MissingTriangularRequirementException(const std::string &err):std::runtime_error(err)
+  {
+    std::cout << "Mesh has to be composed by triangle and not polygons -" << err << "- \n";
+  }
+
+    virtual const char *what() const throw ()
+    {
+      static char buf[128]="Mesh has to be composed by triangle and not polygons";
+      return buf;
+    }
+};
 }
 
 #endif // EXCEPTION_H