AAE+STK Gists

AAE+STKGists.m

//NOTE: 
//THIS GIST IS PART OF A LARGER iOS MUSIC APP DEVELOPMENT TUTORIAL, WHICH I'LL POST SHORTLY.
//Follow http://twitter.com/arivocals for updates


/***************************
DOWNLOAD LINKS FOR LIBRARIES:
STK:
http://momu.stanford.edu/stk/release/momu-stk-1.0.0.tgz

AAE: 
git clone --depth=1 https://github.com/TheAmazingAudioEngine/TheAmazingAudioEngine.git
https://github.com/TheAmazingAudioEngine/TheAmazingAudioEngine/archive/master.zip

AAE Setup Instructions:
http://theamazingaudioengine.com/doc/_getting-_started.html
***************************/ 






//LISTING 1
//Setting up AEAudioController

self.audioController = [[AEAudioController alloc]
                        initWithAudioDescription:[AEAudioController nonInterleavedFloatStereoAudioDescription]
                        inputEnabled:NO
                        ];

NSError *errorAudioSetup = NULL;
BOOL result = [_audioController start:&errorAudioSetup];
if ( !result ) {
    NSLog(@"Error starting audio engine: %@", errorAudioSetup.localizedDescription);
}





//LISTING 2
//Setting up the STK's Mandolin within an AEBlockChannel

self.myMandolin = new stk::Mandolin(400);
self.myMandolin->setFrequency(400);

self.myMandolinChannel = [AEBlockChannel channelWithBlock:^(const AudioTimeStamp  *time,
                                                         UInt32           frames,
                                                         AudioBufferList *audio) {
    for ( int i=0; i<frames; i++ ) {
        
        ((float*)audio->mBuffers[0].mData)[i] =
        ((float*)audio->mBuffers[1].mData)[i] = self.myMandolin->tick();
        
    }
}];

[self.audioController addChannels:@[self.myMandolinChannel]];





//LISTING 3
//Adding an STK Effect within an AEBlockFilter

self.myChorus = new stk::Chorus(500);
self.myChorus->setModFrequency(500);
self.myChorus->setEffectMix(1);

self.myFilter = [AEBlockFilter filterWithBlock:^(AEAudioControllerFilterProducer producer, void *producerToken, const AudioTimeStamp *time, UInt32 frames, AudioBufferList *audio) {
    
    OSStatus status = producer(producerToken, audio, &frames);
    if ( status != noErr ) return;
    
    for (int i = 0; i<frames; i++) {
        
        ((float*)audio->mBuffers[0].mData)[i] = self.myChorus->tick(((float*)audio->mBuffers[0].mData)[i]);
        ((float*)audio->mBuffers[1].mData)[i] = self.myChorus->tick(((float*)audio->mBuffers[1].mData)[i]);
        
    }
}];

[self.audioController addFilter:self.myFilter toChannel:self.myMandolinChannel];





//LISTING 4
//Adding a reverb Audio Unit

NSError *errorReverbSetup = NULL;
self.myReverb = [[AEAudioUnitFilter alloc] initWithComponentDescription:AEAudioComponentDescriptionMake(kAudioUnitManufacturer_Apple, kAudioUnitType_Effect, kAudioUnitSubType_Reverb2) audioController:self.audioController error:&errorReverbSetup];

if (errorReverbSetup) {
    NSLog(@"Error setting up reverb: %@", errorReverbSetup.localizedDescription);
}

[self.audioController addFilter:self.myReverb toChannel:self.myMandolinChannel];





//LISTING 5
//Change one of the parameters of the reverb:

-(IBAction)sliderMoved:(UISlider *)sender{
    AudioUnitSetParameter(self.myReverb.audioUnit, kReverb2Param_DryWetMix, kAudioUnitScope_Global, 0, sender.value, 0);
    NSLog(@"dry wet set to %f", sender.value);
}





//LISTING 6
//checkResult code for functions that return OSStatus

#define checkResult(result,operation) (_checkResult((result),(operation),strrchr(__FILE__, '/')+1,__LINE__))
static inline BOOL _checkResult(OSStatus result, const char *operation, const char* file, int line) {
    if ( result != noErr ) {
        NSLog(@"%s:%d: %s result %d %08X %4.4s\n", file, line, operation, (int)result, (int)result, (char*)&result); 
        return NO;
    }
    return YES;
}