public void checkDrag() {
    Land land = (Land) getWorld();
    if (Greenfoot.mouseDragged(this)) {
      MouseInfo mouse = Greenfoot.getMouseInfo();
      if (cost <= land.getMoneyAmount()) {
        if (hasTurret == false) {
          land.removeObjects(land.getObjects(Radius.class));

          machineGun = new MachineGun_Turret();
          getWorld().addObject(machineGun, mouse.getX(), mouse.getY());
          hasTurret = true;
          land.setMoneyCounter(-cost);
        }
      }
      if (hasTurret == true) machineGun.setLocation(mouse.getX(), mouse.getY());
    }
    if ((Greenfoot.mouseDragEnded(null)) && (machineGun != null)) {
      grid();
      if (machineGun.checkLocation()) {
        machineGun.placed = true;
        hasTurret = false;
        machineGun = null;
      } else {
        land.removeObject(machineGun);
        machineGun = null;
        land.setMoneyCounter(cost);
        hasTurret = false;
      }
    }
  }
  public void grid() {
    Land land = (Land) getWorld();
    int maxWidthNum = land.getWidth() / 50;
    int maxHeightNum = land.getHeight() / 50;
    int x = 0;
    int y = 0;

    int x1 = 0;
    int x2 = 0;
    int y1 = 0;
    int y2 = 0;
    int xAdd = 0;
    int yAdd = 0;
    if (land.map == 1) {
      x1 = 25;
      x2 = -25;
      y1 = 0;
      y2 = -50;
      xAdd = 0;
      yAdd = 25;
    } else if (land.map == 2 || land.map == 3) {
      x1 = 0;
      x2 = -50;
      y1 = 25;
      y2 = -25;
      xAdd = 25;
      yAdd = 0;
    }
    for (int i = 1; i < maxWidthNum; i++) {
      if ((((i * 50) - (machineGun.getX())) <= x1) && (((i * 50) - (machineGun.getX())) >= x2))
        x = (i * 50);
    }

    for (int i = 1; i < maxHeightNum; i++) {
      if ((((i * 50) - (machineGun.getY())) <= y1) && (((i * 50) - (machineGun.getY())) >= y2))
        y = (i * 50);
    }
    machineGun.setLocation(x + xAdd, y + yAdd);
  }