Gaming Your Way

May contain nuts.

Bitwise AND, IF and a big WTF

So what's wrong with this code:

if (this._iDrawLayer & ChipsGame.VIEW_LAYER_A == ChipsGame.VIEW_LAYER_A) {
// draw contents of layer A ...

nothing, really. Nonetheless it's not working in CS3 (yet again, prove me wrong).

Basically it's just the unoptimized check if a certain bit is set or not. Let's do some traces:

trace ("with ():", ((this._iDrawLayer & ChipsGame.VIEW_LAYER_A) == ChipsGame.VIEW_LAYER_A))
trace ("without ():", (this._iDrawLayer & ChipsGame.VIEW_LAYER_A == ChipsGame.VIEW_LAYER_A))
trace ("values :", this._iDrawLayer & ChipsGame.VIEW_LAYER_A , ChipsGame.VIEW_LAYER_A)

The result is this:

with (): true
without (): 1
values: 1 1

Interesting, isn't it?
It seems like the compiler chains the & and the == for some reason that escapes me...

So if you get something undesiered with bitwise operators ... use ( and ) around it.


Happy Halloween


Meet Petal

As way of a slight added bonus, click here to expand your mind ( Or make yourself feel sick, it'll be one or the other ).


Vector Bobs

Another quick break down of an effect in 651.


On paper this is quite impressive, 500 3D objects with depth of field running over a skybox. In real life, it's not exactly rocket science.

Although we used Papervision in 651, we didn't for the effect itself ( Just for the skybox, which uses the background from Orbs as it's texture ).

We start by creating the 3D objects and giving them random x,y,z coords ( For the very best introduction to 3D movement in Flash check these excellent tuts on Kirupa, everything you need for an effect like this is there ).

Right, we're spinning some objects around in 3D space, what about the depth sorting ?
This is just between us right ? It's not going any further ?
Ok then. We just don't bother. It's a very old trick ( I remember doing it back on the Amiga ). If the vector bobs are translucent enough, it's pretty hard to tell if they're not being z-sorted correctly. Looking at that grab above quickly I can't see anything too wrong in terms of sorting, and even if there was, the bobs would all have moved in the demo before you really notice it.
By dropping the sorting we've got more cpu power for more objects, and the more the merrier.

Next up, depth of field. Such a buzzy thing in Flash atm. We all know it's only a blur filter, but depth of field sounds so much cooler. To avoid an extra hit we pre-calculate each blur frame, we're not blurring in real time. Or even using the blur filter itself as it's all done in PaintShop Pro ( And each frame is imported into Flash ).
Each bob is a movieclip ( Which feels very old school already ) and when we're calculating the scale ( Based on it's z property, ie how close or far away from the camera it is ) we can also gotoAndStop() to the correct level of bluriness.

So to recap, the 3D code can be found in some great tuts, there's no z sorting, the depth of field is gotoAndStop and the skybox was done in about 10 lines of code. Drop a nice image over the top of some scanlines and it's all done.

It may seem like I'm talking the effect down quite a bit. I'm not really, it looks sweet, I just don't like people acting like their code is l33t and they're so clever for doing it. Smoke and mirrors is as good a technique as clever code, and there's not always a need to mystify everything.


The sound of silience ...

Back again!

After a good deal of time I finally have something to post about - or let's face it moan about.

As the headling slightly might suggest I'm dealing with sound today.
I think that sound handling in AS3 is a nightmare compared to the ease of it in AS1/2 and I'm not the only one asking WTF?

So in order to play your sound you have to instanciate it, if it's exported CS3 kindly creates a class for you so you can easily use it ... (loading it from an external source is another story)

This is what the CS3 help gives us for embeded sounds ("working with embeded sounds"):

var drum:DrumSound = new DrumSound();
var channel:SoundChannel =;

My first question was: what do I need the SoundChannel for if I just want to play the sound?

Well, the rocket scientists at Adobe thought that it would be a good idea to add a play() command to the Sound, but not a stop(), so in order to stop our sound playing we *need* the SoundChannel - so we better store it for later use.

Anyway, to make my life easier I converted my SoundUtil class from AS2, basically it deals with the sounds so I don't have to think about it, it has a few usefull commands like playSFX (plays a sound effect, once), playMusic (which allows fading), crossfade ...
I usually used attached sounds (or from an external swf, but the SoundUtil dealt with it ...)
So in order to play music for the menu I'd just do:

SoundUtil.getInstance().playMusic("musicName", 2); // 2 would do a 2 sec. fade in

The AS3 version should work the same, although it uses static functions which then call the singleton's method.

Oh wait. We need to have a class to start the embeded sound ...

To get over that I wrote the add method, which basically takes the name of the sound (or the classname) and then does it's magic.

        public function add (strSound:String, bIsMusic:Boolean):void {
            var refClass:Class = getDefinitionByName(strSound) as Class;
            var sndTmp:Sound = new refClass();
            var iTmp:int = this._aSound.length;
            this._objSound[strSound] = { id:iTmp, bIsMusic: bIsMusic };
            if (bIsMusic) {
                this._objSound[strSound].spDummy = new Sprite();

Ha! that was easy ...

As you see the sounds name gets stored in an object (I just use it as dictionairy), I store an Object with some more values along with the name. And you surely might ask WHY on earth I did create a Sprite for music files ...
Well I'm a lamer, I use the Sprite to attach an onEnterFrameTo it for things like fading :)

Fast forward ...

k. Let's say we play some music, and only wont it to play 2 times, after that the sound should be removed from memory. Luckily we have the onSoundComplete Event, it should return (CS3 help): "The Sound object on which a sound has finished playing."

For me it reads like it returns the Sound that is playing. FAIL!

It does however return a SoundChannel, which of course HAS no information (prove me wrong) about the Sound it belongs to ...
So how can I unload/cleanup a Sound when an onSoundComplete occurs, if I don't know which Sound is playing (and don't want to write a seperate Listner for each sound)?

Oh lucky me...

Thank fuck I store a lot of things in my information object (not only what is shown in the add method), for instance I store the SoundChannel I got from Sound's play() command and I store if a Sound is playing ...

After a few hours of using our favorite search engine I came up with something so stupid it might even be brilliant ...

private function onSoundComplete (e:Event):void {
      var strKey:String;
      for (strKey in this._objSound) {
           if (this._objSound[strKey].bIsMusic) {
               if (this._objSound[strKey].chChannel == {
                   this._objSound[strKey].chChannel.removeEventListener(Event.SOUND_COMPLETE, this.onSoundComplete);
                   this._objSound[strKey].bIsPlaying = false;
                   // do some cleanup

Basically I loop over all music "files" that are playing and *compare* their SoundChannel with the one returned by the Event.
That's so insanely stupid! But it works. Sweet.

Maybe it helps some of you ...


Infinite bobs

Here's another really old trick we used in 651.


Way back in Amigaland software sprites ( ie, sprites which were plotted by the blitter as opposed to being hardware based, like a mouse pointer ) were called "Bobs" ( Blitter OBjects ). As with everything you could only ever run a certain amount before you started running out of cpu time, so when the first infinite bob effects started appearing in demos every one passed a little bit of involuntary wee.

// Bob properties
        private var ball:Sprite;
        private var bm1:BitmapData;
        private var bm2:BitmapData;
        private var bm3:BitmapData;
        private var bmData1:Bitmap;
        private var bmData2:Bitmap;
        private var bmData3:Bitmap;

        private var currentBitmapNumber:int;

Just set up 3 bitmaps, and then...

//Set up the sprites
            container=new Sprite();
            playField=new Sprite();

Create a holder sprite + add it to the stage, and then a further sprite within that. Also add your bob to the playField ( Not the container or the stage )

Next up, our mainloop,

        private function mainloop(e:Event):void{

moveBob() is however you want to move the bob around the screen, use your nice sin based movement that you've got tucked away. All it's doing is just moving one bob ( ball:Sprite in this case ) around the screen.

The funky bit is the copyBitmap() method,


        private function copyBitmap():void{


It just simply loops through all our bitmaps, copying what's in our playField ( ie the ball ) to the next bitmap. Just written down like this it's a bit tricky to grasp, think of it like an old flick book. You move the bob, you take a copy of the whole screen and store that in a bitmap and then display that, you then move the bob again, and take another grab of it and so on. We use 3 bitmaps because the image will be slightly different on all of them, creating the sense of movement ( Otherwise it wouldn't animate and would just look like a trail behind the bob ).

I can recommend giving it a quick play, it'll take 5 mins to set yourself up with a working example and once it's running infront of you it'll click into place how it actually does work.



How it does what it does.

Now 651 is history I thought it may be of interest to go through how some of the parts work.

Let's start with the boring bit for today, the actual structure. To make testing it easier, and to be able to swap and change the order to make sure it felt right, I used a pretty simple yet modular approach,

// Demo classes
        private var logo:Logo;
        private var credits:Credits;
        private var twister:Twister;
        private var vectorBalls:VectorBalls;
        private var pimp:Pimp;
        private var showReel:ShowReel;
        private var water:Water;
        private var fin:Fin;
        private var sequenceOrder:Array=new Array("logo","twister","vectorBalls","pimp","credits","showReel","water","fin");
        private var sequenceOffset:int;

The sequenceOrder array kinda speaks for itself. The other part of the code is just as straight forward:

        public function sequence():void{
            switch (sequenceOrder[sequenceOffset]){
                case "logo":
                    logo=new Logo();
                case "twister":
                    twister=new Twister();
                case "credits":
                    credits=new Credits();
                case "vectorBalls":
                    vectorBalls=new VectorBalls();
                case "pimp":
                    pimp=new Pimp();
                case "showReel":
                    showReel=new ShowReel();
                case "water":
                    water=new Water();
                case "fin":
                    fin=new Fin();

        public function finished():void{
            } else {

Each segment is totally independent, ie it has it's own init and housekeeping routines, there's no co-dependency at all. To start the demo the sequenceOffset var is set to 0 and then the sequence() method is called.
When a segment has finished, it calls it's houseKeeping() method to dispose of all the bitmaps and removes all the sprites from the stage, and then calls the finished() method ( Hence it being public ).

That's all there is to the underlying structure which runs the demo, it really doesn't get any more straight forward.


cs3 ? That's so last week

A couple of days late posting it here, but it gave everyone an extra couple of days to save up.

Flash CS4 is out now, here's the launch video ( Of the whole huge cs4 package )

Want something for free ? I know I do. Well here's the link to the FP10 download,

And seeing how we're a developer blog, here's a direct link to the standalone / debug versions

Early feedback seems to show that FP10 is faster in quite a few areas which is great news ( And credit to Adobe for squeezing even more speed out of as3 ).
Like a virgin, I'm saving myself before I get down and dirty with the new player, but as before when we have some interesting tests to post here we will.



Here's a little grab of what I've been working on during my current down time.


Part show-reel / part demo. Coming soon.