Classes/MusicCubePlayback.m

/*
     File: MusicCubePlayback.m
 Abstract: Defines the audio playback object for the application. The object responds to the OpenAL environment.
  Version: 1.3
 
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#import "MusicCubePlayback.h"
#import "MyOpenALSupport.h"
 
 
@implementation MusicCubePlayback
 
@synthesize isPlaying = _isPlaying;
@synthesize wasInterrupted = _wasInterrupted;
@synthesize listenerRotation = _listenerRotation;
 
#pragma mark Object Init / Maintenance
 
void interruptionListener(  void *  inClientData,
                            UInt32  inInterruptionState)
{
    MusicCubePlayback *THIS = (MusicCubePlayback*)inClientData;
    if (inInterruptionState == kAudioSessionBeginInterruption)
    {
        // do nothing
        [THIS teardownOpenAL];
        if ([THIS isPlaying]) {
            THIS->_wasInterrupted = YES;
            THIS->_isPlaying = NO;
        }
    }
    else if (inInterruptionState == kAudioSessionEndInterruption)
    {
        OSStatus result = AudioSessionSetActive(true);
        if (result) printf("Error setting audio session active! %d\n", (int)result);
        [THIS initOpenAL];
        if (THIS->_wasInterrupted)
        {
            [THIS startSound];          
            THIS->_wasInterrupted = NO;
        }
    }
}
 
- (id)init
{   
    if (self = [super init]) {
        // initial position of the sound source and 
        // initial position and rotation of the listener
        // will be set by the view
        
        // setup our audio session
        OSStatus result = AudioSessionInitialize(NULL, NULL, interruptionListener, self);
        if (result) printf("Error initializing audio session! %d\n", (int)result);
        else {
            UInt32 category = kAudioSessionCategory_AmbientSound;
            result = AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(category), &category);
            if (result) printf("Error setting audio session category! %d\n", (int)result);
            else {
                result = AudioSessionSetActive(true);
                if (result) printf("Error setting audio session active! %d\n", (int)result);
            }
        }
        
        _wasInterrupted = NO;
        
        // Initialize our OpenAL environment
        [self initOpenAL];
    }
    
    return self;
}
 
- (void)dealloc
{
    if (_data) free(_data);
        
    [self teardownOpenAL];
    [super dealloc];
}
 
#pragma mark OpenAL
 
- (void) initBuffer
{
    ALenum  error = AL_NO_ERROR;
    ALenum  format = 0;
    ALsizei size = 0;
    ALsizei freq = 0;
    
    NSBundle*               bundle = [NSBundle mainBundle];
    
    // get some audio data from a wave file
    CFURLRef fileURL = (CFURLRef)[[NSURL fileURLWithPath:[bundle pathForResource:@"sound" ofType:@"wav"]] retain];
    
    if (fileURL)
    {   
        _data = MyGetOpenALAudioData(fileURL, &size, &format, &freq);
        CFRelease(fileURL);
        
        if((error = alGetError()) != AL_NO_ERROR) {
            printf("error loading sound: %x\n", error);
            exit(1);
        }
        
        // use the static buffer data API
        alBufferDataStaticProc(_buffer, format, _data, size, freq);
        
        if((error = alGetError()) != AL_NO_ERROR) {
            printf("error attaching audio to buffer: %x\n", error);
        }       
    }
    else
    {
        printf("Could not find file!\n");
        _data = NULL;
    }
}
 
- (void) initSource
{
    ALenum error = AL_NO_ERROR;
    alGetError(); // Clear the error
    
    // Turn Looping ON
    alSourcei(_source, AL_LOOPING, AL_TRUE);
    
    // Set Source Position
    alSourcefv(_source, AL_POSITION, _sourcePos);
    
    // Set Source Reference Distance
    alSourcef(_source, AL_REFERENCE_DISTANCE, 0.15f);
    
    // attach OpenAL Buffer to OpenAL Source
    alSourcei(_source, AL_BUFFER, _buffer);
    
    if((error = alGetError()) != AL_NO_ERROR) {
        printf("Error attaching buffer to source: %x\n", error);
        exit(1);
    }   
}
 
 
- (void)initOpenAL
{
    ALenum          error;
    ALCcontext      *newContext = NULL;
    ALCdevice       *newDevice = NULL;
    
    // Create a new OpenAL Device
    // Pass NULL to specify the system’s default output device
    newDevice = alcOpenDevice(NULL);
    if (newDevice != NULL)
    {
        // Create a new OpenAL Context
        // The new context will render to the OpenAL Device just created 
        newContext = alcCreateContext(newDevice, 0);
        if (newContext != NULL)
        {
            // Make the new context the Current OpenAL Context
            alcMakeContextCurrent(newContext);
            
            // Create some OpenAL Buffer Objects
            alGenBuffers(1, &_buffer);
            if((error = alGetError()) != AL_NO_ERROR) {
                printf("Error Generating Buffers: %x", error);
                exit(1);
            }
            
            // Create some OpenAL Source Objects
            alGenSources(1, &_source);
            if(alGetError() != AL_NO_ERROR) 
            {
                printf("Error generating sources! %x\n", error);
                exit(1);
            }
            
        }
    }
    // clear any errors
    alGetError();
    
    [self initBuffer];  
    [self initSource];
}
 
- (void)teardownOpenAL
{
    ALCcontext  *context = NULL;
    ALCdevice   *device = NULL;
    
    // Delete the Sources
    alDeleteSources(1, &_source);
    // Delete the Buffers
    alDeleteBuffers(1, &_buffer);
    
    //Get active context (there can only be one)
    context = alcGetCurrentContext();
    //Get device for active context
    device = alcGetContextsDevice(context);
    //Release context
    alcDestroyContext(context);
    //Close device
    alcCloseDevice(device);
}
 
#pragma mark Play / Pause
 
- (void)startSound
{
    ALenum error;
    
    printf("Start!\n");
    // Begin playing our source file
    alSourcePlay(_source);
    if((error = alGetError()) != AL_NO_ERROR) {
        printf("error starting source: %x\n", error);
    } else {
        // Mark our state as playing
        self.isPlaying = YES;
    }
}
 
- (void)stopSound
{
    ALenum error;
    
    printf("Stop!!\n");
    // Stop playing our source file
    alSourceStop(_source);
    if((error = alGetError()) != AL_NO_ERROR) {
        printf("error stopping source: %x\n", error);
    } else {
        // Mark our state as not playing
        self.isPlaying = NO;
    }
}
 
#pragma mark Setters / Getters
 
- (float*)sourcePos
{
    return _sourcePos;
}
 
- (void)setSourcePos:(float*)SOURCEPOS
{
    int i;
    for (i=0; i<3; i++)
        _sourcePos[i] = SOURCEPOS[i];
    
    // Move our audio source coordinates
    alSourcefv(_source, AL_POSITION, _sourcePos);
}
 
 
 
- (float*)listenerPos
{
    return _listenerPos;
}
 
- (void)setListenerPos:(float*)LISTENERPOS
{
    int i;
    for (i=0; i<3; i++)
        _listenerPos[i] = LISTENERPOS[i];
    
    // Move our listener coordinates
    alListenerfv(AL_POSITION, _listenerPos);
}
 
 
 
- (float)listenerRotation
{
    return _listenerRotation;
}
 
- (void)setListenerRotation:(float)radians
{
    _listenerRotation = radians;
    float ori[] = {0., cos(radians), sin(radians), 1., 0., 0.};
    // Set our listener orientation (rotation)
    alListenerfv(AL_ORIENTATION, ori);
}
 
@end