So, background music is not as simple as playing a sound effect, because

a sound effect is simply an ASCI action and you run that action.

Now with background music we have to tap into the AV foundation framework.

Um,don't worry, I'm gonna walk you through the whole process.

So, back in our Space Cap Assets folder, in the

Music folder you'll see that we have three separate MP3 files.

So, this is going to be for our Start screen.

So, if you press the Space bar, you can hear that, it's a pretty funky beat.

[MUSIC]

And that's the Game placing with that deep thump, which, I kinda dig.

[MUSIC]

And then you have a game over MP3 file.

So, what we wanna do here is we wanna select all these

three MP3 files and we'll drag them over to our Sounds folder.

Once again making sure that you have copy

items selected, and you have add to target selected.

So hit Finish.

All right, next thing what we'll do is we'll add our foundation framework.

So click on Space Cat as the project and where it says Linked Frameworks

and Libraries, click on the plus sign and look for AVFoundation.

There, that's the first one.

So you double click on that and you'll see that it's been added to your project.

So, head on over to your THTitleScene.

The first thing we'll do is we'll import.

So #import AvFoundation, Foundation.

Next, what we'll do is we'll have to set up our Player.

So, before we can set up our Player, let's create a

property, so that we can reference that Player from different methods.

So, we'll say property nonatomic AVAudioPlayer.

They have different players.

There's a video player, there's a player.

So, make sure that you select the AVAudioPlayer.

I will call this backgroundMusic.

And then in our initWithSize method we'll set up our background music.

So we'll say music is equal to AVAudioPlayer alloc.

And then say, initWithContentsOfURL.

Now, we'll need a URL that points to the start screen MP3 file.

Cuz that's the MP3 file that we're gonna play for our title scene.

Now remember, background basically just loops continuously in the background.

So we need not worry about the file format.

Here you can easily use the MP3 file format because once it

loads it, it's just gonna loop it over and over and over again.

It's not going to be playing multiple of these sounds at the

same time or playing a hundred of these sounds at the same time.

So we can work with the MP3 file format but we

need to give to AVI audio player the location of this file.

So let's create a NSURL.

We'll see URL is equal to NSBundle, mainBundle.

Because this is going to be bundled with our application,

so we need to look for it in our application bundle.

We'll say URLForResource, and then give it

the name StartScreen with extension MP3.

And this is going to return us a URL.

And now you can easily use this

URL in our initWithContentsOfFiles, so we'll say initWithContentsOfURL:url.

Error, we'll just pass it nil.

Next we'll do self.backgroundMusic.numberOfLoops.

So number of times that you want this music to loop.

In our case, it's indefinitely until the player moves on to the next screen.

So we'll just say minus one.

Which is repeat infinitely.

And the last thing we need to do is we need to call a method prepareToPlay.

So essentially this is going to load up the file from that URL

and it's just going to have it ready so we can play it.

Now when do we play this?

Well we can't play it in the init method.

We want to play it as soon as that scene is drawn on the screen, and for that we're

going to use a method, or we're going to override that method, didMoveToView.

So essentially didMoveToView is kind of like viewDidLoad for your view controller.

So this would be the ideal place for us to play that background music.

So we'll do self.backgroundMusic play.

Now of course if you've played background music somewhere you do need to stop it.

So the minute the player touches our screen

we're going to stop our background music, because we're

going to play another background track the minute

the user goes over to the game play scene.

So let's run our game.

[MUSIC]

And there, we get this nice little track playing the minute the scene loads.

[SOUND] Isn't that a funky little jam?

All right.

Now onto our game play scene.

[BLANK_AUDIO]

So, similarly we're going to first import our AVFoundation.

[BLANK_AUDIO]

And then next we're gonna set up a property for our background music.

I'm thinking we'll just call this backgroundMusic.

And then in our setupSounds.

Cuz we have this nice little method called setupSounds.

This is where we're going to set up our sound.

So, so, I am just going to head on over to the title scene and I am just gonna

copy all that code, because you know, I mean, the

only thing that changes is the name of the file.

So, I am just going to change that to game play.

And once again, we have our prepareToPlay, so all we need to

do is, we need to make sure that we have our didMoveToView.

So we'll do didMoveToView, and we'll

do self.backgroundMusic and call the play method.

So the minute the player moves from the title scene

to the gameplay scene he'll hear a different background music.

[MUSIC]

So quite frankly I love the game play scene because it has

that deep thump to it, but that might just be a personal preference.

So there you have it.

We successfully added background music and sound effects to our game.