public void getTiles(XQuadTree treeNode) { if (!treeNode.isHasChild()) { // this is the leaf node Rectangle2D.Double tile_rect = treeNode.getM_rect(); Point2D.Double offsetPoint = new Point2D.Double(tile_rect.getX(), tile_rect.getY()); X2DGrid grid = new X2DGrid(tile_rect, this.cell_size, offsetPoint); this.m_tiles.put(treeNode.getIndex(), grid); } else { this.getTiles(treeNode.getM_tl_child()); this.getTiles(treeNode.getM_tr_child()); this.getTiles(treeNode.getM_bl_child()); this.getTiles(treeNode.getM_br_child()); } }