Welcome back!

We are going on in programming a simple money money clone, here. It is very simple. If you lost the previous lesson, please read it in the previous posts. Anyway, shortly it is a game in which you control a character in the lower part of the screen with your mouse to catch objects falling from the ceiling (or to avoid objects, of course).

I left you with some main concept about the object dispatcher. Now we are going to make it in actionscript.

Up to now, we have in our library two objects exported via the linkage name of “coin” and “hammer”. We only have to attach them dynamically to the stage and let them fall.

We have to decide where to attach movies from the library. For this example, we are going to attach them to the root timeline, but in some cases it is useful to attach them to a container movieclip.

At the same moment we start playing this game, the objects must be started to fall down too. So we are going to add something similar to the code below to the main action layer.

nint = setInterval(crObject, 1000, this);
curr++;
score_txt.text = String(score
energy_txt.text = String(energy);

This lines will be useful to initialize the event dispatcher (1), increasing the number of the current object, and displaying initialized values for score and energy.
The setInterval function takes three parameters, the function to be called at the specified interval, the interval and one or more parameters to pass to the variable. So we are telling the actionscript compiler to call the crObject function each 1000 milliseconds (1 second), passing the address of the current timeline as a parameter (for reference).

Of course, we have to initialize some variables in the context of our game. We can add at the very beginning of the code, this code that initializes the variables needed in the game.

var curr:Number = 0;
var energy:Number = 100;
var score:Number = 0;
var nint:Number;

This code initializes the variables for object number (curr), energy and score and a variable (nint) that represents the interval at which calling the function to create objects.

Now we need the last function to make it all work. I will leave the architecture open, so you are going to use this code for games like this one. I prefer to comment in the code, hoping this will be more clear.

function crObject(root:MovieClip) {
// casual object, the number will be interpreted later
tipo = Math.round(Math.random()*1);
// increase the current object number,
// so objects will not replace themselves at any creation.
curr++;
// this will decide if coin or hammer from the tipo number.
tipo_mc = (tipo == 0) ? "coin" : "hammer";
// the object is now created, attached to the root timeline,
// and it get the name of objectN where N is curr and placed
// at level 1024 + curr.
objmc = root.attachMovie(tipo_mc, "object"+curr, 1024+curr);
// defines the starting position of objects.
objmc._x = Math.round(Math.random()*340)+30;
objmc._y = -20;
// defines falling rate of the object
objmc.fstep = 2;
// stores the type of the object in the object.
objmc.tipo = tipo;
// randomize the scale of the object
objmc._xscale = objmc._yscale=Math.round(Math.random()*50)+50;
// this code is executed during the fall of the object
objmc.onEnterFrame = function() {
// falling
this._y += this.fstep;
// increase falling rate
this.fstep += 0.2;
// increase rotation of the object
this._rotation += 5;
// when the object collides with the main char
if (this.hitTest(root.char) == true) {
// depending on tipo acts in a different way
switch (this.tipo) {
case 0 :
// if type is coin, increase the score
score += 10;
break;
case 1 :
// if type is hammer, lose energy.
// If energy falls under 0, go to GameOver frame.
energy -= 10;
if (energy <= 0) {
clearInterval(nint);
root.gotoAndStop("gameover");
}
break;
}
// updates score and energy
score_txt.text = String(score);
energy_txt.text = String(energy);
// remove this clip
this.removeMovieClip();
}
// if, instead, objects falls under
// the lower limit of the stage, simply remove it.
if (this._y>450) {
this.removeMovieClip();
}
};
}

The game is done. You should test it and try to understand each single piece of code. This is very simple, next time we are going to see how to develop a more complex game. This was just to put you in the right mood.

Now create a home for your game, a game over frame and you are ready to go online.

If something went wrong, please download the complete fla from here.

See you soon!