Best Practices with Sound « cocos2d for iPhone

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Best Practices with Sound

(18 posts) (5 voices)

Started 2 years ago by tatebn
Latest reply from tatebn

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CocosDenshion

tatebn
Member

I posted earlier about the ball demo I've been messing with. I have a bunch of them moving and colliding, and I'm having a blast learning this stuff. Here's my question. I've added a collisionPairFunction to have a sound play when they collide (right now just NSLog output), but there's so many of them and when they just sit on top of each other it goes crazy and locks up. So. What are the best practices for monitoring sound play? Is there anything built in or will I have to come up with something myself? Basically I want a collision sound, but a realistic collision sound that doesn't play 50 times a second.

Thanks

Posted 2 years ago #
Steve Oldmeadow
Administrator

If you use CocosDenshion and CDAudioManager then you can set up a channel group to be non interruptible, this means all sounds played on that channel group will be played to completion. The machine gun sample in the demo is set up this way - just two channels in the group that play a machine gun sound until completion. You can see that no matter how many times you hit the pad you will only ever hear two sounds.

However, I would recommend you combine this with some logic of your own so that you don't trigger sounds unnecessarily, for example if a ball is involved in 10 collisions during a frame you probably only want to play a sound once. This would imply you don't trigger the sound playing from the collision function. One possibility is to simply record collision events in the collision function and then process them in a scheduled selector (tick) that plays sounds appropriately.

Posted 2 years ago #
tatebn
Member

Where is that machine gun demo? Buy the way, you're kind of my hero on this stuff.

Posted 2 years ago #
tatebn
Member

I'm using 0.7.2 by the way. Not sure if that makes a difference.

Posted 2 years ago #
shivaz
Member

I think you will want to use 0.8 - at least if you want to use CocosDenshion - I think the demo that Steve mentioned is in there. Haven't gotten to sound myself yet - but am getting there!

As to the collision stuff - I think Steve's idea is a good one. It would also speed the code up a bit by just setting a collided variable in the collision detection function. That way once something is done about the collision the variable can be reset and the function will be available again.

Justin

Posted 2 years ago #
Steve Oldmeadow
Administrator

@tatebn - shivaz is correct, CocosDenshion is part of 0.8. However, it is compatible with older versions of cocos2d so you don't have to upgrade to 0.8 to use it. The best way to get it is from the svn repository http://code.google.com/p/cocos2d-iphone/source/checkout since it has changed a bit since the 0.8 beta was released.

The demo is called (strangely enough) CocosDenshionDemo in the cocos2d project.

I use svnX which is a svn gui for MacOS X to get stuff from the svn repository.

Posted 2 years ago #
tatebn
Member

I've go too much of this stuff working to switch it up now. I'd rather find a sound solution for 0.7.2. There has to be a way to do it easily. Not trying to deal with a bunch of complex sound management logic.

Not sure what you mean by the collision variable. I would like the proper motion to be calculated for all collisions.

Posted 2 years ago #
Steve Oldmeadow
Administrator

Maybe I didn't make it clear enough: you can use CocosDenshion with 0.7.2.

Posted 2 years ago #
tatebn
Member

sorry. I responded without refreshing. I didn't see your post until just now.

Posted 2 years ago #
tatebn
Member

But the more I think about it, if I have balls clinking together, I'll probably want them to play over top of each other. They'll be quick 1 second sounds. Just not excessively.

Posted 2 years ago #
Steve Oldmeadow
Administrator

The problem is the most sounds you can play back simultaneously is 32. If sounds are triggered rapidly you can quickly run out of voices and you end up getting a weird flamming effect as you only ever hear the start of the sounds. You may find simply setting up a channel group with 32 voices but set to non interruptible (so that the sounds play completely) is all you need.

Also, the point I was trying to make was not that you don't want multiple clinking noises at the same time but that you probably only want to trigger one such sound per ball during a frame.

Posted 2 years ago #
crmagicxxx
Member

Your problem is with Chipmunk's inability to properly detect persistent collisions. I hear that Box2D has that ability, but didn't test it.

So, basically, when your objects sit on each other and you think they are fine, they are actually triggering CollisionPair function all the time. So just setting the sound there is not good.

Listen what Steve told you, and make your own game logic to play sound. But it'll not be easy at all, I still didn't find a proper way. For example, you have ground and falling objects. To play just one sound when object hits the ground is simple problem (try subclassing your sprite/body/shape with some BOOL like BOOL touchedGround, and then set that BOOL only on first detected collision and play sound for that object only if touchedGround is true). But there's another problem, if that object starts to rotate, fall on another object there, and so on, you'll probably want to play sound again. Well, that's more problems and I didn't have time to calculate all of this to play proper sounds with "not-so-moving/bouncing" objects...

Posted 2 years ago #
tatebn
Member

I've been trying to get the sound working. I've having trouble with linking. What frameworks are necessary?

Posted 2 years ago #
tatebn
Member

It can't find $_AVAudioPlayer

Posted 2 years ago #
tatebn
Member

AVFoundation framework. Got that far.

Posted 2 years ago #
Codemattic
Moderator

Im linking openal, coreaudio, audiotoolbox.

Posted 2 years ago #
tatebn
Member

I think I have everything set up, but no sound plays. Any theories.

Posted 2 years ago #
tatebn
Member

Got it. Sorry. Had the loop set to 0 in init.

Posted 2 years ago #

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