Index: trunk/nv/interface/vertex_buffer.hh
===================================================================
--- trunk/nv/interface/vertex_buffer.hh	(revision 154)
+++ trunk/nv/interface/vertex_buffer.hh	(revision 155)
@@ -107,4 +107,12 @@
 			}
 		}
+		void update_vertex_buffer( int location, size_t offset ) 
+		{
+			auto i = m_map.find( location );
+			if ( i != m_map.end() )
+			{
+				i->second->m_offset = offset;
+			}
+		}
 		void set_index_buffer( index_buffer* buffer, datatype datatype, bool owner ) 
 		{