/* Define the gravity. This determines how fast the balls are pulled down. */
var gravity:Number = 0.4;
 
//Create 128 balls in the for-loop (change this to whatever you want)
for (var i = 0; i < 128; i++) {
 
        //Create a ball
        var ball:MovieClip = new MovieClip();
 
        //Call the function that draws a circle on the ball movie clip
        drawGraphics (ball);
 
        //Initial position of the ball
        ball.x = stage.stageWidth / 2;
        ball.y = stage.stageHeight;
 
        //Define a random x and y speed for the ball
        ball.speedX = Math.random() * 2 - 1;
        ball.speedY = Math.random() * -8 - 4;
 
        //Add the ball to the stage
        addChild (ball);
 
        //ENTER_FRAME function is responsible for animating the ball
        ball.addEventListener (Event.ENTER_FRAME, moveBall);
}
 
/* This function is responsible for drawing a circle on a movie clip given as parameter */
function drawGraphics (mc:MovieClip):void {
 
        //Give a random color for the circle
        mc.graphics.beginFill (0xffffff *  Math.random());
 
        //Draw the cirlce
        mc.graphics.drawCircle (0, 0, 3);
 
        //End the filling
        mc.graphics.endFill ();
}

//This function is responsible for animation a ball
function moveBall (e:Event):void {
 
        //Let's assign the ball to a local variable
        var ball:MovieClip = (MovieClip)(e.target);
 
        //Apply gravity tot the y speed
        ball.speedY += gravity;
 
        //Update the ball's postion
        ball.x += ball.speedX;
        ball.y += ball.speedY;
 
        //Chech if the ball has gone under the stage
        if (ball.y > stage.stageHeight) {
 
                /* Calculate the mouse height. We use the mouse height to give the ball a new random y speed */
                var mouseHeight:Number = stage.stageHeight - mouseY;
 
                //Calculate the new y speed
                var newSpeedY = Math.random() * (-mouseHeight * 0.05);
 
                //Move the ball to the initial position
                ball.x = stage.stageWidth / 2;
                ball.y = stage.stageHeight;
 
                //Assign the new calculated random speeds for the ball
                ball.speedX = Math.random() * 2 - 1;
                ball.speedY = newSpeedY;
        }
}