public void drawFloorWall(FloorWall floorWall) {
   batcher.drawSprite(
       floorWall.position.x,
       floorWall.position.y,
       FloorWall.WALL_WIDTH,
       FloorWall.WALL_HEIGHT,
       regions[floorWall.type]);
 }
  private void renderBackground() {
    FloorWall[][] floorsWalls = world.floorsWalls;
    List<EnemySpawner> spawnerList = world.spawnerList;

    batcher.beginBatch(levelTexture);

    for (int i = 0; i < floorsWalls.length; i++) {
      for (int j = 0; j < floorsWalls[i].length; j++) {
        FloorWall wall = floorsWalls[i][j];
        drawFloorWall(wall);
      }
    }

    for (int i = 0; i < spawnerList.size(); i++) {
      EnemySpawner spawner = spawnerList.get(i);
      drawSpawner(spawner);
    }

    batcher.endBatch();

    // TODO second batch run for GUI and foreground items.
  }