Sound state (playing, looping) support in SoundEngine.cpp

I have recently compared AVAudioPlayer with SoundEngine with the verdict that short of using AudioQueue, SoundEngine.cpp was better, at least for now.

The problem I faced with it is that it doesn't support query of the sound's states. This is not crucial, but because a game I was working on as a lot of objects falling at the same time, I wanted sounds to play simultaneously. I found it difficult to do if I couldn't find out if a sound is playing to start with.

I saw the same question poping up on some forums, with the usual answer being "use AVAudioPlayer", which is kind of a daft answer. So here is the simple changes I made to the original SoundEngine.h and SoundEngine.cpp to add support for the states.

Add this to the end of SoundEngine.h :

bool  SoundEngine_EffectIsPlaying(UInt32 inEffectID);
bool  SoundEngine_EffectIsLooping(UInt32 inEffectID);

This in SoundEngine.cpp, in the SoundEngineEffect class :

ALenum GetState()
{
ALenum state;
alGetSourcei(mSourceID, AL_SOURCE_STATE, &state);
return state;
}

Add this in the same file, but in the OpenALObject class

bool EffectIsPlaying(UInt32 inEffectID)
{
SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
return (theEffect) ? (theEffect->GetState() == AL_PLAYING) : kSoundEngineErrInvalidID;
}
bool EffectIsLooping(UInt32 inEffectID)
{
SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
return (theEffect) ? (theEffect->GetState() == AL_LOOPING) : kSoundEngineErrInvalidID;
}

This is pretty self explanatory. GetState returns other values, like AL_PAUSED or AL_STOPPED, so the same method could be used for the whole range of states.

And finally, in the same file (SoundEngine.cpp), near the end where the Extern stuff is declared :

extern "C"
OSStatus  SoundEngine_SetMaxDistance(Float32 inValue)
{
return (sOpenALObject) ? sOpenALObject->SetMaxDistance(inValue) : kSoundEngineErrUnitialized;
}

extern "C"
OSStatus  SoundEngine_SetReferenceDistance(Float32 inValue)
{
return (sOpenALObject) ? sOpenALObject->SetReferenceDistance(inValue) : kSoundEngineErrUnitialized;
}

You can then use SoundEngine_EffectIsPlaying() and SoundEngine_EffectIsLooping() to query the sound's states.