public void AddFallingObjects(){
        int x = (int)(Math.random() * ((maxFallingRange - minlFallingRange) + 1));
        
        rainDrop = new 
                RainDrop(x,0,"/Images/rain_drop.png");
                    fallingObjects.add(rainDrop);
        
        int fallingObjectType = minFallingObjectType + (int)(Math.random() * 
                ((maxFallingObejctType - minFallingObjectType) + 1));
        
        //if multiple falling object exists
//        switch(fallingObjectType){
//            case 1:
//                 rainDrop = new 
//                        RainDrop(x,0,"/Images/rain_drop.png");
//                            fallingObjects.add(rainDrop);
//                break;
//            case 2:
//                  umbrella = new 
//                Umbrella(x,0,"/Images/umbrella.png");
//                    fallingObjects.add(umbrella);
//                break;
//        }
    }