code: public static Xml exports(TileRef tileRef)
      {
          Check.notNull(tileRef);
  
          final Xml node = new Xml(NODE_TILE);
          node.writeInteger(ATT_TILE_SHEET, tileRef.getSheet().intValue());
          node.writeInteger(ATT_TILE_NUMBER, tileRef.getNumber());
  
          return node;
      }
docs: Export the tile as a node.
  
  @param tileRef The tile to export (must not be <code>null</code>).
  @return The exported node.
  @throws LionEngineException If <code>null</code> argument or error on writing.