Torque2D/engine/source/platformiOS/SoundEngine.mm

//-----------------------------------------------------------------------------
// Copyright (c) 2013 GarageGames, LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//-----------------------------------------------------------------------------

/*
 
 ===== IMPORTANT =====
 
 This is sample code demonstrating API, technology or techniques in development.
 Although this sample code has been reviewed for technical accuracy, it is not
 final. Apple is supplying this information to help you plan for the adoption of
 the technologies and programming interfaces described herein. This information
 is subject to change, and software implemented based on this sample code should
 be tested with final operating system software and final documentation. Newer
 versions of this sample code may be provided with future seeds of the API or
 technology. For information about updates to this and other developer
 documentation, view the New & Updated sidebars in subsequent documentation
 seeds.
 
 =====================
 
 File: SoundEngine.cpp
 Abstract: These functions play background music tracks, multiple sound effects,
 and support stereo panning with a low-latency response.
 
 Version: 1.6
 
 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Inc.
 ("Apple") in consideration of your agreement to the following terms, and your
 use, installation, modification or redistribution of this Apple software
 constitutes acceptance of these terms.  If you do not agree with these terms,
 please do not use, install, modify or redistribute this Apple software.
 
 In consideration of your agreement to abide by the following terms, and subject
 to these terms, Apple grants you a personal, non-exclusive license, under
 Apple's copyrights in this original Apple software (the "Apple Software"), to
 use, reproduce, modify and redistribute the Apple Software, with or without
 modifications, in source and/or binary forms; provided that if you redistribute
 the Apple Software in its entirety and without modifications, you must retain
 this notice and the following text and disclaimers in all such redistributions
 of the Apple Software.
 Neither the name, trademarks, service marks or logos of Apple Inc. may be used
 to endorse or promote products derived from the Apple Software without specific
 prior written permission from Apple.  Except as expressly stated in this notice,
 no other rights or licenses, express or implied, are granted by Apple herein,
 including but not limited to any patent rights that may be infringed by your
 derivative works or by other works in which the Apple Software may be
 incorporated.
 
 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO
 WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
 COMBINATION WITH YOUR PRODUCTS.
 
 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR
 DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF
 CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF
 APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 Copyright (C) 2008 Apple Inc. All Rights Reserved.
 
 */

//==================================================================================================
//	Includes
//==================================================================================================

//	System Includes
#include <AudioToolbox/AudioToolbox.h>
#include <CoreFoundation/CFURL.h>
#include <OpenAL/al.h>
#include <OpenAL/alc.h>
#include <map>
#include <vector>
#include <pthread.h>
#include <mach/mach.h>

// Local Includes
#include "SoundEngine.h"

namespace SoundEngine {


#define	AssertNoError(inMessage, inHandler) \
if(result != noErr) \
{	 \
printf("%s: %d\n", inMessage, (int)result);	 \
}

#define AssertNoOALError(inMessage, inHandler)					\
if((result = alGetError()) != AL_NO_ERROR)			\
{													\
printf("%s: %x\n", inMessage, (int)result);		\
goto inHandler;									\
}

#define kNumberBuffers 3

class OpenALObject;
class BackgroundTrackMgr;

static OpenALObject			*sOpenALObject = NULL;
static BackgroundTrackMgr	*sBackgroundTrackMgr = NULL;
static Float32				gMasterVolumeGain = 1.0;

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
typedef ALvoid	AL_APIENTRY	(*alBufferDataStaticProcPtr) (const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq);
ALvoid  alBufferDataStaticProc(const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq)
{
    static	alBufferDataStaticProcPtr	proc = NULL;
    
    if (proc == NULL) {
        proc = (alBufferDataStaticProcPtr) alcGetProcAddress(NULL, (const ALCchar*) "alBufferDataStatic");
    }
    
    if (proc)
        proc(bid, format, data, size, freq);
    
    return;
}

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
typedef ALvoid	AL_APIENTRY	(*alcMacOSXMixerOutputRateProcPtr) (const ALdouble value);
ALvoid  alcMacOSXMixerOutputRateProc(const ALdouble value)
{
    static	alcMacOSXMixerOutputRateProcPtr	proc = NULL;
    
    if (proc == NULL) {
        proc = (alcMacOSXMixerOutputRateProcPtr) alcGetProcAddress(NULL, (const ALCchar*) "alcMacOSXMixerOutputRate");
    }
    
    if (proc)
        proc(value);
    
    return;
}

#pragma mark ***** OpenALThread *****
//==================================================================================================
//	Threading functions
//==================================================================================================
class	OpenALThread
    {
        // returns the thread's priority as it was last set by the API
#define OpenALThread_SET_PRIORITY				0
        // returns the thread's priority as it was last scheduled by the Kernel
#define OpenALThread_SCHEDULED_PRIORITY		1
        
        //	Types
    public:
        typedef void*			(*ThreadRoutine)(void* inParameter);
        
        //	Constants
    public:
        enum
        {
            kMinThreadPriority = 1,
            kMaxThreadPriority = 63,
            kDefaultThreadPriority = 31
        };
        
        //	Construction/Destruction
    public:
        OpenALThread(ThreadRoutine inThreadRoutine, void* inParameter)
        :	mPThread(0),
        mSpawningThreadPriority(getScheduledPriority(pthread_self(), OpenALThread_SET_PRIORITY)),
        mThreadRoutine(inThreadRoutine),
        mThreadParameter(inParameter),
        mPriority(kDefaultThreadPriority),
        mFixedPriority(false),
        mAutoDelete(true) { }
        
        ~OpenALThread() { }
        
        //	Properties
        bool IsRunning() const { return 0 != mPThread; }
        void SetAutoDelete(bool b) { mAutoDelete = b; }
        
        void SetPriority(UInt32 inPriority, bool inFixedPriority)
        {
            OSStatus result = noErr;
            mPriority = inPriority;
            mFixedPriority = inFixedPriority;
            if(mPThread != 0)
            {
                if (mFixedPriority)
                {
                    thread_extended_policy_data_t		theFixedPolicy;
                    theFixedPolicy.timeshare = false;	// set to true for a non-fixed thread
                    result  = thread_policy_set(pthread_mach_thread_np(mPThread), THREAD_EXTENDED_POLICY, (thread_policy_t)&theFixedPolicy, THREAD_EXTENDED_POLICY_COUNT);
                    if (result) {
                        printf("OpenALThread::SetPriority: failed to set the fixed-priority policy");
                        return;
                    }
                }
                // We keep a reference to the spawning thread's priority around (initialized in the constructor), 
                // and set the importance of the child thread relative to the spawning thread's priority.
                thread_precedence_policy_data_t		thePrecedencePolicy;
                
                thePrecedencePolicy.importance = mPriority - mSpawningThreadPriority;
                result =thread_policy_set(pthread_mach_thread_np(mPThread), THREAD_PRECEDENCE_POLICY, (thread_policy_t)&thePrecedencePolicy, THREAD_PRECEDENCE_POLICY_COUNT);
                if (result) {
                    printf("OpenALThread::SetPriority: failed to set the precedence policy");
                    return;
                }
            } 
        }
        //	Actions
        void Start()
        {
            if(mPThread != 0)
            {
                printf("OpenALThread::Start: can't start because the thread is already running\n");
                return;
            }
            
            OSStatus			result;
            pthread_attr_t		theThreadAttributes;
            
            result = pthread_attr_init(&theThreadAttributes);
            AssertNoError("Error initializing thread", end);
            
            result = pthread_attr_setdetachstate(&theThreadAttributes, PTHREAD_CREATE_DETACHED);
            AssertNoError("Error setting thread detach state", end);
            
            result = pthread_create(&mPThread, &theThreadAttributes, (ThreadRoutine)OpenALThread::Entry, this);
            AssertNoError("Error creating thread", end);
            
            pthread_attr_destroy(&theThreadAttributes);
            AssertNoError("Error destroying thread attributes", end);
        end:
            return;
        }
        
        //	Implementation
    protected:
        static void* Entry(OpenALThread* inOpenALThread)
        {
            void* theAnswer = NULL;
            
            inOpenALThread->SetPriority(inOpenALThread->mPriority, inOpenALThread->mFixedPriority);
            
            if(inOpenALThread->mThreadRoutine != NULL)
            {
                theAnswer = inOpenALThread->mThreadRoutine(inOpenALThread->mThreadParameter);
            }
            
            inOpenALThread->mPThread = 0;
            if (inOpenALThread->mAutoDelete)
                delete inOpenALThread;
            return theAnswer;
        }
        
        static UInt32 getScheduledPriority(pthread_t inThread, int inPriorityKind)
        {
            thread_basic_info_data_t			threadInfo;
            policy_info_data_t					thePolicyInfo;
            unsigned int						count;
            
            if (inThread == NULL)
                return 0;
            
            // get basic info
            count = THREAD_BASIC_INFO_COUNT;
            thread_info (pthread_mach_thread_np (inThread), THREAD_BASIC_INFO, (thread_info_t)&threadInfo, &count);
            
            switch (threadInfo.policy) {
                case POLICY_TIMESHARE:
                    count = POLICY_TIMESHARE_INFO_COUNT;
                    thread_info(pthread_mach_thread_np (inThread), THREAD_SCHED_TIMESHARE_INFO, (thread_info_t)&(thePolicyInfo.ts), &count);
                    if (inPriorityKind == OpenALThread_SCHEDULED_PRIORITY) {
                        return thePolicyInfo.ts.cur_priority;
                    }
                    return thePolicyInfo.ts.base_priority;
                    break;
                    
                case POLICY_FIFO:
                    count = POLICY_FIFO_INFO_COUNT;
                    thread_info(pthread_mach_thread_np (inThread), THREAD_SCHED_FIFO_INFO, (thread_info_t)&(thePolicyInfo.fifo), &count);
                    if ( (thePolicyInfo.fifo.depressed) && (inPriorityKind == OpenALThread_SCHEDULED_PRIORITY) ) {
                        return thePolicyInfo.fifo.depress_priority;
                    }
                    return thePolicyInfo.fifo.base_priority;
                    break;
                    
                case POLICY_RR:
                    count = POLICY_RR_INFO_COUNT;
                    thread_info(pthread_mach_thread_np (inThread), THREAD_SCHED_RR_INFO, (thread_info_t)&(thePolicyInfo.rr), &count);
                    if ( (thePolicyInfo.rr.depressed) && (inPriorityKind == OpenALThread_SCHEDULED_PRIORITY) ) {
                        return thePolicyInfo.rr.depress_priority;
                    }
                    return thePolicyInfo.rr.base_priority;
                    break;
            }
            
            return 0;
        }
        
        pthread_t				mPThread;
        UInt32					mSpawningThreadPriority;
        ThreadRoutine			mThreadRoutine;
        void*					mThreadParameter;
        SInt32					mPriority;
        bool					mFixedPriority;
        bool					mAutoDelete;		// delete self when thread terminates
    };

//==================================================================================================
//	Helper functions
//==================================================================================================
OSStatus OpenFile(const char *inFilePath, AudioFileID &outAFID)
{
    
    CFURLRef theURL = CFURLCreateFromFileSystemRepresentation(kCFAllocatorDefault, (UInt8*)inFilePath, strlen(inFilePath), false);
    if (theURL == NULL)
        return kSoundEngineErrFileNotFound;
    
#if TARGET_OS_iOS
    OSStatus result = AudioFileOpenURL(theURL, fsRdPerm, 0, &outAFID);
#else
    OSStatus result = AudioFileOpenURL(theURL, kAudioFileReadPermission, 0, &outAFID);
#endif
    CFRelease(theURL);
    AssertNoError("Error opening file", end);
end:
    return result;
}

OSStatus LoadFileDataInfo(const char *inFilePath, AudioFileID &outAFID, AudioStreamBasicDescription &outFormat, UInt64 &outDataSize)
{
    UInt32 thePropSize = sizeof(outFormat);				
    OSStatus result = OpenFile(inFilePath, outAFID);
    if( result != noErr ) {
        int a = 0;
        a++;
    } else {
        int a = 0;
        a++;
    }
    AssertNoError("Error opening file", end);
    
    result = AudioFileGetProperty(outAFID, kAudioFilePropertyDataFormat, &thePropSize, &outFormat);
    AssertNoError("Error getting file format", end);
    
    thePropSize = sizeof(UInt64);
    result = AudioFileGetProperty(outAFID, kAudioFilePropertyAudioDataByteCount, &thePropSize, &outDataSize);
    AssertNoError("Error getting file data size", end);
    
end:
    return result;
}

void CalculateBytesForTime (AudioStreamBasicDescription & inDesc, UInt32 inMaxPacketSize, Float64 inSeconds, UInt32 *outBufferSize, UInt32 *outNumPackets)
{
    static const UInt32 maxBufferSize = 0x10000; // limit size to 64K
    static const UInt32 minBufferSize = 0x4000; // limit size to 16K
    
    if (inDesc.mFramesPerPacket) {
        Float64 numPacketsForTime = inDesc.mSampleRate / inDesc.mFramesPerPacket * inSeconds;
        *outBufferSize = numPacketsForTime * inMaxPacketSize;
    } else {
        // if frames per packet is zero, then the codec has no predictable packet == time
        // so we can't tailor this (we don't know how many Packets represent a time period
        // we'll just return a default buffer size
        *outBufferSize = maxBufferSize > inMaxPacketSize ? maxBufferSize : inMaxPacketSize;
    }
    
    // we're going to limit our size to our default
    if (*outBufferSize > maxBufferSize && *outBufferSize > inMaxPacketSize)
        *outBufferSize = maxBufferSize;
    else {
        // also make sure we're not too small - we don't want to go the disk for too small chunks
        if (*outBufferSize < minBufferSize)
            *outBufferSize = minBufferSize;
    }
    *outNumPackets = *outBufferSize / inMaxPacketSize;
}

static Boolean MatchFormatFlags(const AudioStreamBasicDescription& x, const AudioStreamBasicDescription& y)
{
    UInt32 xFlags = x.mFormatFlags;
    UInt32 yFlags = y.mFormatFlags;
    
    // match wildcards
    if (x.mFormatID == 0 || y.mFormatID == 0 || xFlags == 0 || yFlags == 0) 
        return true;
    
    if (x.mFormatID == kAudioFormatLinearPCM)
    {		 		
        // knock off the all clear flag
        xFlags = xFlags & ~kAudioFormatFlagsAreAllClear;
        yFlags = yFlags & ~kAudioFormatFlagsAreAllClear;
        
        // if both kAudioFormatFlagIsPacked bits are set, then we don't care about the kAudioFormatFlagIsAlignedHigh bit.
        if (xFlags & yFlags & kAudioFormatFlagIsPacked) {
            xFlags = xFlags & ~kAudioFormatFlagIsAlignedHigh;
            yFlags = yFlags & ~kAudioFormatFlagIsAlignedHigh;
        }
        
        // if both kAudioFormatFlagIsFloat bits are set, then we don't care about the kAudioFormatFlagIsSignedInteger bit.
        if (xFlags & yFlags & kAudioFormatFlagIsFloat) {
            xFlags = xFlags & ~kAudioFormatFlagIsSignedInteger;
            yFlags = yFlags & ~kAudioFormatFlagIsSignedInteger;
        }
        
        //	if the bit depth is 8 bits or less and the format is packed, we don't care about endianness
        if((x.mBitsPerChannel <= 8) && ((xFlags & kAudioFormatFlagIsPacked) == kAudioFormatFlagIsPacked))
        {
            xFlags = xFlags & ~kAudioFormatFlagIsBigEndian;
        }
        if((y.mBitsPerChannel <= 8) && ((yFlags & kAudioFormatFlagIsPacked) == kAudioFormatFlagIsPacked))
        {
            yFlags = yFlags & ~kAudioFormatFlagIsBigEndian;
        }
        
        //	if the number of channels is 0 or 1, we don't care about non-interleavedness
        if (x.mChannelsPerFrame <= 1 && y.mChannelsPerFrame <= 1) {
            xFlags &= ~kLinearPCMFormatFlagIsNonInterleaved;
            yFlags &= ~kLinearPCMFormatFlagIsNonInterleaved;
        }
    }
    return xFlags == yFlags;
}

Boolean FormatIsEqual(AudioStreamBasicDescription x, AudioStreamBasicDescription y)
{
    //	the semantics for equality are:
    //		1) Values must match exactly
    //		2) wildcard's are ignored in the comparison
    
#define MATCH(name) ((x.name) == 0 || (y.name) == 0 || (x.name) == (y.name))
    
    return 
    ((x.mSampleRate==0.) || (y.mSampleRate==0.) || (x.mSampleRate==y.mSampleRate)) 
    && MATCH(mFormatID)
    && MatchFormatFlags(x, y)  
    && MATCH(mBytesPerPacket) 
    && MATCH(mFramesPerPacket) 
    && MATCH(mBytesPerFrame) 
    && MATCH(mChannelsPerFrame) 		
    && MATCH(mBitsPerChannel) ;
}

#pragma mark ***** BackgroundTrackMgr *****
//==================================================================================================
//	BackgroundTrackMgr class
//==================================================================================================
class BackgroundTrackMgr
    {	
#define CurFileInfo THIS->mBGFileInfo[THIS->mCurrentFileIndex]
    public:
        typedef struct BG_FileInfo {
            const char*						mFilePath;
            AudioFileID						mAFID;
            AudioStreamBasicDescription		mFileFormat;
            UInt64							mFileDataSize;
            //UInt64							mFileNumPackets; // this is only used if loading file to memory
            Boolean							mLoadAtOnce;
            Boolean							mIsPlaying;//-Mat added this
            Boolean							mFileDataInQueue;
        } BackgroundMusicFileInfo;
        
        BackgroundTrackMgr() 
        :	mQueue(0),
        mBufferByteSize(0),
        mCurrentPacket(0),
        mNumPacketsToRead(0),
        mVolume(1.0),
        mPacketDescs(NULL),
        mCurrentFileIndex(0),
        mMakeNewQueueWhenStopped(false),
        mStopAtEnd(false) { }
        
        ~BackgroundTrackMgr() { Teardown(); }
        
        void Teardown()
        {
            if (mQueue)
                AudioQueueDispose(mQueue, true);
            for (UInt32 i=0; i < mBGFileInfo.size(); i++)
                if (mBGFileInfo[i]->mAFID)
                    AudioFileClose(mBGFileInfo[i]->mAFID);
            
            if (mPacketDescs)
            {
                delete mPacketDescs;
                mPacketDescs = NULL;
            }
        }
        
        AudioStreamPacketDescription *GetPacketDescsPtr() { return mPacketDescs; }
        
        UInt32 GetNumPacketsToRead(BackgroundTrackMgr::BG_FileInfo *inFileInfo) 
        { 
            return mNumPacketsToRead; 
        }
        
        static OSStatus AttachNewCookie(AudioQueueRef inQueue, BackgroundTrackMgr::BG_FileInfo *inFileInfo)
        {
            OSStatus result = noErr;
            UInt32 size = sizeof(UInt32);
            result = AudioFileGetPropertyInfo (inFileInfo->mAFID, kAudioFilePropertyMagicCookieData, &size, NULL);
            if (!result && size) 
            {
                char* cookie = new char [size];		
                result = AudioFileGetProperty (inFileInfo->mAFID, kAudioFilePropertyMagicCookieData, &size, cookie);
                AssertNoError("Error getting cookie data", end);
                result = AudioQueueSetProperty(inQueue, kAudioQueueProperty_MagicCookie, cookie, size);
                delete [] cookie;
                AssertNoError("Error setting cookie data for queue", end);
            }
            return noErr;
            
        end:
            return noErr;
        }
        
        static void QueueStoppedProc(	void *                  inUserData,
                                     AudioQueueRef           inAQ,
                                     AudioQueuePropertyID    inID)
        {
            UInt32 isRunning;
            UInt32 propSize = sizeof(isRunning);
            
            BackgroundTrackMgr *THIS = (BackgroundTrackMgr*)inUserData;
            OSStatus result = AudioQueueGetProperty(inAQ, kAudioQueueProperty_IsRunning, &isRunning, &propSize);
            
            if ((!isRunning) && (THIS->mMakeNewQueueWhenStopped))
            {
                result = AudioQueueDispose(inAQ, true);
                AssertNoError("Error disposing queue", end);
                result = THIS->SetupQueue(CurFileInfo);
                AssertNoError("Error setting up new queue", end);
                result = THIS->SetupBuffers(CurFileInfo);
                AssertNoError("Error setting up new queue buffers", end);
                result = THIS->Start();
                AssertNoError("Error starting queue", end);
            }
        end:
            return;
        }
        
        static Boolean DisposeBuffer(AudioQueueRef inAQ, std::vector<AudioQueueBufferRef> inDisposeBufferList, AudioQueueBufferRef inBufferToDispose)
        {
            for (unsigned int i=0; i < inDisposeBufferList.size(); i++)
            {
                if (inBufferToDispose == inDisposeBufferList[i])
                {
                    OSStatus result = AudioQueueFreeBuffer(inAQ, inBufferToDispose);
                    if (result == noErr)
                        inDisposeBufferList.pop_back();
                    return true;
                }
            }
            return false;
        }
        
        enum {
            kQueueState_DoNothing		= 0,
            kQueueState_ResizeBuffer	= 1,
            kQueueState_NeedNewCookie	= 2,
            kQueueState_NeedNewBuffers	= 3,
            kQueueState_NeedNewQueue	= 4,
        };
        
        static SInt8 GetQueueStateForNextBuffer(BackgroundTrackMgr::BG_FileInfo *inFileInfo, BackgroundTrackMgr::BG_FileInfo *inNextFileInfo)
        {
            inFileInfo->mFileDataInQueue = false;
            
            // unless the data formats are the same, we need a new queue
            if (!FormatIsEqual(inFileInfo->mFileFormat, inNextFileInfo->mFileFormat))
                return kQueueState_NeedNewQueue;
            
            // if going from a load-at-once file to streaming or vice versa, we need new buffers
            if (inFileInfo->mLoadAtOnce != inNextFileInfo->mLoadAtOnce)
                return kQueueState_NeedNewBuffers;
            
            // if the next file is smaller than the current, we just need to resize
            if (inNextFileInfo->mLoadAtOnce)
                return (inFileInfo->mFileDataSize >= inNextFileInfo->mFileDataSize) ? kQueueState_ResizeBuffer : kQueueState_NeedNewBuffers;
            
            return kQueueState_NeedNewCookie;
        }
        
        static void QueueCallback(	void *					inUserData,
                                  AudioQueueRef			inAQ,
                                  AudioQueueBufferRef		inCompleteAQBuffer) 
        {
            // dispose of the buffer if no longer in use
            OSStatus result = noErr;
            BackgroundTrackMgr *THIS = (BackgroundTrackMgr*)inUserData;
            if (DisposeBuffer(inAQ, THIS->mBuffersToDispose, inCompleteAQBuffer))
                return;
            UInt32 nPackets = 0;
            //-Mat 
            if (CurFileInfo->mIsPlaying == false)
            {
                result = AudioQueueStop(inAQ, false);
                AssertNoError("Error stopping queue", end);
                return;
            }
            // loop the current buffer if the following:
            // 1. file was loaded into the buffer previously
            // 2. only one file in the queue
            // 3. we have not been told to stop at playlist completion
            if ((CurFileInfo->mFileDataInQueue) && (THIS->mBGFileInfo.size() == 1) && (!THIS->mStopAtEnd))
                nPackets = THIS->GetNumPacketsToRead(CurFileInfo);
            
            else
            {
                UInt32 numBytes;
                while (nPackets == 0)
                {
                    // if loadAtOnce, get all packets in the file, otherwise ~.5 seconds of data
                    nPackets = THIS->GetNumPacketsToRead(CurFileInfo);					
                    result = AudioFileReadPackets(CurFileInfo->mAFID, false, &numBytes, THIS->mPacketDescs, THIS->mCurrentPacket, &nPackets, 
                                                  inCompleteAQBuffer->mAudioData);
                    AssertNoError("Error reading file data", end);
                    
                    inCompleteAQBuffer->mAudioDataByteSize = numBytes;	
                    
                    if (nPackets == 0) // no packets were read, this file has ended.
                    {
                        if (CurFileInfo->mLoadAtOnce)
                            CurFileInfo->mFileDataInQueue = true;
                        
                        THIS->mCurrentPacket = 0;
                        UInt32 theNextFileIndex = (THIS->mCurrentFileIndex < THIS->mBGFileInfo.size()-1) ? THIS->mCurrentFileIndex+1 : 0;
                        
                        // we have gone through the playlist. if mStopAtEnd, stop the queue here
                        if (theNextFileIndex == 0 && THIS->mStopAtEnd)
                        {
                            result = AudioQueueStop(inAQ, false);
                            AssertNoError("Error stopping queue", end);
                            return;
                        }					
                        SInt8 theQueueState = GetQueueStateForNextBuffer(CurFileInfo, THIS->mBGFileInfo[theNextFileIndex]);
                        if (theNextFileIndex != THIS->mCurrentFileIndex)
                        {
                            // if were are not looping the same file. Close the old one and open the new
                            result = AudioFileClose(CurFileInfo->mAFID);
                            AssertNoError("Error closing file", end);
                            THIS->mCurrentFileIndex = theNextFileIndex;
                            
                            result = LoadFileDataInfo(CurFileInfo->mFilePath, CurFileInfo->mAFID, CurFileInfo->mFileFormat, CurFileInfo->mFileDataSize);
                            AssertNoError("Error opening file", end);
                        }
                        
                        switch (theQueueState) 
                        {							
                                // if we need to resize the buffer, set the buffer's audio data size to the new file's size
                                // we will also need to get the new file cookie
                            case kQueueState_ResizeBuffer:
                                inCompleteAQBuffer->mAudioDataByteSize = CurFileInfo->mFileDataSize;							
                                // if the data format is the same but we just need a new cookie, attach a new cookie
                            case kQueueState_NeedNewCookie:
                                result = AttachNewCookie(inAQ, CurFileInfo);
                                AssertNoError("Error attaching new file cookie data to queue", end);
                                break;
                                
                                // we can keep the same queue, but not the same buffer(s)
                            case kQueueState_NeedNewBuffers:
                                THIS->mBuffersToDispose.push_back(inCompleteAQBuffer);
                                THIS->SetupBuffers(CurFileInfo);
                                break;
                                
                                // if the data formats are not the same, we need to dispose the current queue and create a new one
                            case kQueueState_NeedNewQueue:
                                THIS->mMakeNewQueueWhenStopped = true;
                                result = AudioQueueStop(inAQ, false);
                                AssertNoError("Error stopping queue", end);
                                return;
                                
                            default:
                                break;
                        }
                    }
                }
            }
            result = AudioQueueEnqueueBuffer(inAQ, inCompleteAQBuffer, (THIS->mPacketDescs ? nPackets : 0), THIS->mPacketDescs);
            if(result != noErr) {
                int a = 0;
                a++;
            }
            AssertNoError("Error enqueuing new buffer", end);
            if (CurFileInfo->mLoadAtOnce)
                CurFileInfo->mFileDataInQueue = true;
            
            THIS->mCurrentPacket += nPackets;
            
        end:
            return;
        }
        
        OSStatus SetupQueue(BG_FileInfo *inFileInfo)
        {
            UInt32 size = 0;
            OSStatus result = AudioQueueNewOutput(&inFileInfo->mFileFormat, QueueCallback, this, CFRunLoopGetCurrent(), kCFRunLoopCommonModes, 0, &mQueue);
            AssertNoError("Error creating queue", end);
            
            // (2) If the file has a cookie, we should get it and set it on the AQ
            size = sizeof(UInt32);
            result = AudioFileGetPropertyInfo (inFileInfo->mAFID, kAudioFilePropertyMagicCookieData, &size, NULL);
            
            if (!result && size) {
                char* cookie = new char [size];		
                result = AudioFileGetProperty (inFileInfo->mAFID, kAudioFilePropertyMagicCookieData, &size, cookie);
                AssertNoError("Error getting magic cookie", end);
                result = AudioQueueSetProperty(mQueue, kAudioQueueProperty_MagicCookie, cookie, size);
                delete [] cookie;
                AssertNoError("Error setting magic cookie", end);
            }
            
            // channel layout
            OSStatus err = AudioFileGetPropertyInfo(inFileInfo->mAFID, kAudioFilePropertyChannelLayout, &size, NULL);
            if (err == noErr && size > 0) {
                AudioChannelLayout *acl = (AudioChannelLayout *)malloc(size);
                result = AudioFileGetProperty(inFileInfo->mAFID, kAudioFilePropertyChannelLayout, &size, acl);
                AssertNoError("Error getting channel layout from file", end);
                result = AudioQueueSetProperty(mQueue, kAudioQueueProperty_ChannelLayout, acl, size);
                free(acl);
                AssertNoError("Error setting channel layout on queue", end);
            }
            
            // add a notification proc for when the queue stops
            result = AudioQueueAddPropertyListener(mQueue, kAudioQueueProperty_IsRunning, QueueStoppedProc, this);
            AssertNoError("Error adding isRunning property listener to queue", end);
            
            // we need to reset this variable so that if the queue is stopped mid buffer we don't dispose it 
            mMakeNewQueueWhenStopped = false;
            
            // volume
            result = SetVolume(mVolume);
            
        end:
            return result;
        }
        
        OSStatus SetupBuffers(BG_FileInfo *inFileInfo)
        {
            int numBuffersToQueue = kNumberBuffers;
            UInt32 maxPacketSize;
            UInt32 size = sizeof(maxPacketSize);
            // we need to calculate how many packets we read at a time, and how big a buffer we need
            // we base this on the size of the packets in the file and an approximate duration for each buffer
            
            // first check to see what the max size of a packet is - if it is bigger
            // than our allocation default size, that needs to become larger
            OSStatus result = AudioFileGetProperty(inFileInfo->mAFID, kAudioFilePropertyPacketSizeUpperBound, &size, &maxPacketSize);
            AssertNoError("Error getting packet upper bound size", end);
            bool isFormatVBR = (inFileInfo->mFileFormat.mBytesPerPacket == 0 || inFileInfo->mFileFormat.mFramesPerPacket == 0);
            
            CalculateBytesForTime(inFileInfo->mFileFormat, maxPacketSize, 0.5/*seconds*/, &mBufferByteSize, &mNumPacketsToRead);
            
            // if the file is smaller than the capacity of all the buffer queues, always load it at once
            if ((mBufferByteSize * numBuffersToQueue) > inFileInfo->mFileDataSize)
                inFileInfo->mLoadAtOnce = true;
            
            if (inFileInfo->mLoadAtOnce)
            {
                UInt64 theFileNumPackets;
                size = sizeof(UInt64);
                result = AudioFileGetProperty(inFileInfo->mAFID, kAudioFilePropertyAudioDataPacketCount, &size, &theFileNumPackets);
                AssertNoError("Error getting packet count for file", end);
                
                mNumPacketsToRead = (UInt32)theFileNumPackets;
                mBufferByteSize = inFileInfo->mFileDataSize;
                numBuffersToQueue = 1;
            }	
            else
            {
                mNumPacketsToRead = mBufferByteSize / maxPacketSize;
            }
            
            if (isFormatVBR)
                mPacketDescs = new AudioStreamPacketDescription [mNumPacketsToRead];
            else
                mPacketDescs = NULL; // we don't provide packet descriptions for constant bit rate formats (like linear PCM)	
            
            // allocate the queue's buffers
            for (int i = 0; i < numBuffersToQueue; ++i) 
            {
                result = AudioQueueAllocateBuffer(mQueue, mBufferByteSize, &mBuffers[i]);
                AssertNoError("Error allocating buffer for queue", end);
                QueueCallback (this, mQueue, mBuffers[i]);
                if (inFileInfo->mLoadAtOnce)
                    inFileInfo->mFileDataInQueue = true;
            }
            
        end:
            return result;
        }
        
        OSStatus LoadTrack(const char* inFilePath, Boolean inAddToQueue, Boolean inLoadAtOnce)
        {
            BG_FileInfo *fileInfo = new BG_FileInfo;
            fileInfo->mFilePath = inFilePath;
            OSStatus result = LoadFileDataInfo(fileInfo->mFilePath, fileInfo->mAFID, fileInfo->mFileFormat, fileInfo->mFileDataSize);
            AssertNoError("Error getting file data info", fail);
            fileInfo->mLoadAtOnce = inLoadAtOnce;
            fileInfo->mFileDataInQueue = false;
            // if not adding to the queue, clear the current file vector
            if (!inAddToQueue)
                mBGFileInfo.clear();
            
            fileInfo->mIsPlaying = true;
            mBGFileInfo.push_back(fileInfo);
            
            // setup the queue if this is the first (or only) file
            if (mBGFileInfo.size() == 1)
            {
                result = SetupQueue(fileInfo);
                AssertNoError("Error setting up queue", fail);
                result = SetupBuffers(fileInfo);
                AssertNoError("Error setting up queue buffers", fail);					
            }
            // if this is just part of the playlist, close the file for now
            else
            {
                result = AudioFileClose(fileInfo->mAFID);
                AssertNoError("Error closing file", fail);
            }	
            return result;
            
        fail:
            if (fileInfo)
                delete fileInfo;
            return result;
        }
        
        OSStatus UpdateGain()
        {
            return SetVolume(mVolume);
        }
        
        OSStatus SetVolume(Float32 inVolume)
        {
            mVolume = inVolume;
            return AudioQueueSetParameter(mQueue, kAudioQueueParam_Volume, mVolume * gMasterVolumeGain);
        }
        
        OSStatus Start()
        {
            OSStatus result = AudioQueuePrime(mQueue, 1, NULL);	
            if (result)
            {
                printf("Error priming queue");
                return result;
            }
            //-Mat set mIsPlaying flag
            mBGFileInfo.back()->mIsPlaying = true;
            return AudioQueueStart(mQueue, NULL);
        }
        
        OSStatus Stop(Boolean inStopAtEnd)
        {
            if (inStopAtEnd)
            {
                mStopAtEnd = true;
                return noErr;
            }
            else {
                mBGFileInfo.back()->mIsPlaying = false;
                return AudioQueueStop(mQueue, true);
            }
        }
        
    private:
        AudioQueueRef						mQueue;
        AudioQueueBufferRef					mBuffers[kNumberBuffers];
        UInt32								mBufferByteSize;
        SInt64								mCurrentPacket;
        UInt32								mNumPacketsToRead;
        Float32								mVolume;
        AudioStreamPacketDescription *		mPacketDescs;
        std::vector<BG_FileInfo*>			mBGFileInfo;
        UInt32								mCurrentFileIndex;
        Boolean								mMakeNewQueueWhenStopped;
        Boolean								mStopAtEnd;
        std::vector<AudioQueueBufferRef>	mBuffersToDispose;
    };

#pragma mark ***** SoundEngineEffect *****
//==================================================================================================
//	SoundEngineEffect class
//==================================================================================================
class SoundEngineEffect
    {
    public:	
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        SoundEngineEffect(const char* inLoopPath, const char* inAttackPath, const char* inDecayPath, Boolean inDoLoop) 
        :	mSourceID(0),
        mAttackBufferID(0),
        mLoopBufferID(0),
        mDecayBufferID(0),
        mLoopPath(inLoopPath),
        mAttackPath(inAttackPath),
        mDecayPath(inDecayPath),
        mLoopData(NULL),
        mAttackData(NULL),
        mDecayData(NULL),
        mLoopDataSize(0),
        mAttackDataSize(0),
        mDecayDataSize(0),
        mIsLoopingEffect(inDoLoop),
        mPlayThread(NULL),
        mPlayThreadState(kPlayThreadState_Loop) 
        { 
            
            alGenSources(1, &mSourceID); 
            
        }
        
        ~SoundEngineEffect()
        {
            alDeleteSources(1, &mSourceID);
            
            if (mLoopData)
                free(mLoopData);
            if (mAttackData)
                free(mAttackData);
            if (mDecayData)
                free(mDecayData);
        }
        
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        // Accessors
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        UInt32	GetEffectID() { return mSourceID; }
        UInt32	GetPlayThreadState() { return mPlayThreadState; }
        Boolean	HasAttackBuffer() { return mAttackBufferID != 0; }
        
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        // Helper Functions
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        ALenum GetALFormat(AudioStreamBasicDescription inFileFormat)
        {
            if (inFileFormat.mFormatID != kAudioFormatLinearPCM)
                return kSoundEngineErrInvalidFileFormat;
            
            if ((inFileFormat.mChannelsPerFrame > 2) || (inFileFormat.mChannelsPerFrame < 1))
                return kSoundEngineErrInvalidFileFormat;
            
            if(inFileFormat.mBitsPerChannel == 8)
                return (inFileFormat.mChannelsPerFrame == 1) ? AL_FORMAT_MONO8 : AL_FORMAT_STEREO8;
            else if(inFileFormat.mBitsPerChannel == 16)
                return (inFileFormat.mChannelsPerFrame == 1) ? AL_FORMAT_MONO16 : AL_FORMAT_STEREO16;
            
            return kSoundEngineErrInvalidFileFormat;
        }
        
        OSStatus LoadFileData(const char *inFilePath, void* &outData, UInt32 &outDataSize, ALuint &outBufferID)
        {
            AudioFileID theAFID = 0;
            OSStatus result = noErr;
            UInt64 theFileSize = 0;
            AudioStreamBasicDescription theFileFormat;
            
            result = LoadFileDataInfo(inFilePath, theAFID, theFileFormat, theFileSize);
            outDataSize = (UInt32)theFileSize;
            AssertNoError("Error loading file info", fail)
            
            outData = malloc(outDataSize);
            
            result = AudioFileReadBytes(theAFID, false, 0, &outDataSize, outData);
            AssertNoError("Error reading file data", fail)
            
            if (!TestAudioFormatNativeEndian(theFileFormat) && (theFileFormat.mBitsPerChannel > 8)) 
                return kSoundEngineErrInvalidFileFormat;
            
            alGenBuffers(1, &outBufferID);
            AssertNoOALError("Error generating buffer\n", fail);
            
            alBufferDataStaticProc(outBufferID, GetALFormat(theFileFormat), outData, outDataSize, theFileFormat.mSampleRate);
            AssertNoOALError("Error attaching data to buffer\n", fail);
            
            AudioFileClose(theAFID);
            return result;
            
        fail:			
            if (theAFID)
                AudioFileClose(theAFID);
            if (outData)
            {
                free(outData);
                outData = NULL;
            }
            return result;
        }
        
        OSStatus AttachFilesToSource()
        {
            OSStatus result = AL_NO_ERROR;			
            // first check for the attack file. That will be first in the queue if present
            if (mAttackPath)
            {
                result = LoadFileData(mAttackPath, mAttackData, mAttackDataSize, mAttackBufferID);
                AssertNoError("Error loading attack file info", end)
            }
            
            result = LoadFileData(mLoopPath, mLoopData, mLoopDataSize, mLoopBufferID);
            AssertNoError("Error loading looping file info", end)
            
            // if one-shot effect, attach the buffer to the source now
            if (!mIsLoopingEffect)
            {
                alSourcei(mSourceID, AL_BUFFER, mLoopBufferID);
                AssertNoOALError("Error attaching file data to effect", end)
            }
            
            if (mDecayPath)
            {
                result = LoadFileData(mDecayPath, mDecayData, mDecayDataSize, mDecayBufferID);
                AssertNoError("Error loading decay file info", end)
            }
        end:
            return result;
        }
        
        OSStatus ClearSourceBuffers()
        {
            OSStatus result = AL_NO_ERROR;
            ALint numQueuedBuffers = 0;
            ALuint *bufferIDs = (ALuint*)malloc(numQueuedBuffers * sizeof(ALint));
            alGetSourcei(mSourceID, AL_BUFFERS_QUEUED, &numQueuedBuffers);
            AssertNoOALError("Error getting OpenAL queued buffer size", end)
            
            alSourceUnqueueBuffers(mSourceID, numQueuedBuffers, bufferIDs);
            AssertNoOALError("Error unqueueing buffers from source", end)
            
        end:
            free(bufferIDs);
            return result;
        }
        
        static void* PlaybackProc(void *args)
        {
            OSStatus result = AL_NO_ERROR;
            SoundEngineEffect *THIS = (SoundEngineEffect*)args;
            
            alSourcePlay(THIS->GetEffectID());
            AssertNoOALError("Error starting effect playback", end)
            
            // if attack buffer is present, wait until it has completed, then turn looping on
            if (THIS->HasAttackBuffer())
            {
                ALint numBuffersProcessed = 0;						
                while (numBuffersProcessed < 1)
                {
                    alGetSourcei(THIS->GetEffectID(), AL_BUFFERS_PROCESSED, &numBuffersProcessed);
                    AssertNoOALError("Error getting processed buffer number", end)
                }
                
                ALuint tmpBuffer = 0;
                alSourceUnqueueBuffers(THIS->GetEffectID(), 1, &tmpBuffer);
                AssertNoOALError("Error unqueueing buffers from source", end)
            }
            // now that we have processed the attack buffer, loop the main one
            THIS->SetLooping(true);
            
        end:	
            return NULL;
        }
        
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        // Effect management
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        OSStatus Start()
        {
            OSStatus result = AL_NO_ERROR;				
            alSourceStop(mSourceID);
            AssertNoOALError("Error stopping source", end)
            
            if (!mIsLoopingEffect)
            {
                // if we are just playing one-short effects, start playback here
                alSourcePlay(mSourceID);
                return alGetError();
            }
            // for loops we need to spawn a new thread					
            mPlayThread = new OpenALThread(PlaybackProc, (void*)this);
            // we want this to delete upon thread completion
            mPlayThreadState = kPlayThreadState_Loop;
            // clean up remnants from any previous playback of the source
            result = ClearSourceBuffers();
            AssertNoError("Error clearing buffers", end)
            
            // if the effect has an attack sample, queue this first
            if (HasAttackBuffer())
            {
                alSourceQueueBuffers(mSourceID, 1, &mAttackBufferID);
                AssertNoOALError("Error queueing buffers for attack", end)
                // turn on looping after the attack buffer has been processed
                SetLooping(false);
            }
            
            alSourceQueueBuffers(mSourceID, 1, &mLoopBufferID);
            AssertNoOALError("Error queueing looping buffer", end)
            mPlayThread->Start();
        end:			
            return result;
        }
        
        OSStatus StartDecay()
        {
            // turn off looping, and queue the decay buffer
            OSStatus result = AL_NO_ERROR;
            alSourcei(mSourceID, AL_LOOPING, 0);
            AssertNoOALError("Error turning off looping", end)
            alSourceQueueBuffers(mSourceID, 1, &mDecayBufferID);
            AssertNoOALError("Error queueing decay file", end)
        end:
            return result;
        }
        
        OSStatus Stop(Boolean inDoDecay)
        {
            OSStatus result = AL_NO_ERROR;
            // for non looped effects and loops with no decay sample
            if ((mDecayBufferID == 0) || !inDoDecay)
            {
                // if no decay to play, just stop the source
                alSourceStop(mSourceID);
                AssertNoOALError("Error stopping source", end)
            }
            else
                return StartDecay();
        end:
            return result;
        }
        
        OSStatus SetPitch(Float32 inValue)
        {
            alSourcef(mSourceID, AL_PITCH, inValue);
            return alGetError();
        }
        
        OSStatus SetLooping(Boolean inDoLoop)
        {
            ALint doLoop = inDoLoop ? 1 : 0;
            alSourcei(mSourceID, AL_LOOPING, doLoop);
            return alGetError();
        }
        
        OSStatus SetPosition(Float32 inX, Float32 inY, Float32 inZ)
        {
            alSource3f(mSourceID, AL_POSITION, inX, inY, inZ);
            return alGetError();
        }
        
        OSStatus SetMaxDistance(Float32 inValue)
        {
            alSourcef(mSourceID, AL_MAX_DISTANCE, inValue);
            return alGetError();
        }
        
        OSStatus SetReferenceDistance(Float32 inValue)
        {
            alSourcef(mSourceID, AL_REFERENCE_DISTANCE, inValue);
            return alGetError();
        }
        
        OSStatus SetLevel(Float32 inValue)
        {
            alSourcef(mSourceID, AL_GAIN, inValue * gMasterVolumeGain);
            return alGetError();
        }
        
        enum {
            kPlayThreadState_Loop	= 0,
            kPlayThreadState_Decay	= 1,
            kPlayThreadState_End	= 2
        };
        
    private:
        ALuint					mSourceID;
        ALuint					mAttackBufferID;
        ALuint					mLoopBufferID;
        ALuint					mDecayBufferID;		
        UInt32					mNumberBuffers;
        const char*				mLoopPath;
        const char*				mAttackPath;
        const char*				mDecayPath;
        void*					mLoopData;
        void*					mAttackData;
        void*					mDecayData;
        UInt32					mLoopDataSize;
        UInt32					mAttackDataSize;
        UInt32					mDecayDataSize;
        Boolean					mIsLoopingEffect;
        OpenALThread*			mPlayThread;
        UInt32					mPlayThreadState;
    };

#pragma mark ***** SoundEngineEffectMap *****
//==================================================================================================
//	SoundEngineEffectMap class
//==================================================================================================
class SoundEngineEffectMap 
: std::multimap<UInt32, SoundEngineEffect*, std::less<ALuint> > 
{
public:
    // add a new context to the map
    void Add (const	ALuint	inEffectToken, SoundEngineEffect **inEffect)
    {
        iterator	it = upper_bound(inEffectToken);
        insert(it, value_type (inEffectToken, *inEffect));
    }
    
    SoundEngineEffect* Get(ALuint	inEffectToken) 
    {
        iterator	it = find(inEffectToken);
        if (it != end())
            return ((*it).second);
        return (NULL);
    }
    
    void Remove (const	ALuint	inSourceToken) {
        iterator 	it = find(inSourceToken);
        if (it != end())
            erase(it);
    }
    
    SoundEngineEffect* GetEffectByIndex(UInt32	inIndex) {
        iterator	it = begin();
        
        for (UInt32 i = 0; i < inIndex; i++) {
            if (it != end())
                ++it;
            else
                i = inIndex;
        }
        
        if (it != end())
            return ((*it).second);		
        return (NULL);
    }
    
    iterator GetIterator() { return begin(); }
    
    UInt32 Size () const { return size(); }
    bool Empty () const { return empty(); }
};

#pragma mark ***** OpenALObject *****
//==================================================================================================
//	OpenALObject class
//==================================================================================================
class OpenALObject
    {	
    public:	
        OpenALObject(Float32 inMixerOutputRate)
        :	mOutputRate(inMixerOutputRate),
        mGain(1.0),
        mContext(NULL),
        mDevice(NULL),
        mEffectsMap(NULL) 
        {
            mEffectsMap = new SoundEngineEffectMap();
        }
        
        ~OpenALObject() { Teardown(); }
        
        OSStatus Initialize()
        {
            OSStatus result = noErr;
            mDevice = alcOpenDevice(NULL);
            
            ALenum err = alGetError();			
            int mRequestSources = 16;
            static ALuint                 mSource[16];
            
            
            AssertNoOALError("Error opening output device", end)
            if(mDevice == NULL) { return kSoundEngineErrDeviceNotFound; }
            
            // if a mixer output rate was specified, set it here
            // must be done before the alcCreateContext() call
            if (mOutputRate)
                alcMacOSXMixerOutputRateProc(mOutputRate);
            
            // Create an OpenAL Context
            mContext = alcCreateContext(mDevice, NULL);
            AssertNoOALError("Error creating OpenAL context", end)
            
            alcMakeContextCurrent(mContext);
            AssertNoOALError("Error setting current OpenAL context", end)
            
            
            //we will get a a source as we play it
            while(true)
            {
                alGenSources(1, &mSource[0]);
                err = alGetError();
                if (err == AL_NO_ERROR)
                    break;
                
                mRequestSources--;
                
                if (mRequestSources == 0)
                {
                    return (false);
                }
            }
            
            
            
            
        end:
            return result;
        }
        
        void Teardown()
        {
            if (mEffectsMap) 
            {
                for (UInt32  i = 0; i < mEffectsMap->Size(); i++)
                {
                    SoundEngineEffect	*theEffect = mEffectsMap->GetEffectByIndex(0);
                    if (theEffect)
                    {
                        mEffectsMap->Remove(theEffect->GetEffectID());
                        delete theEffect;
                    }
                }
                delete mEffectsMap;
            }
            
            if (mContext) alcDestroyContext(mContext);
            
            if (mDevice) alcCloseDevice(mDevice);
        }
        
        OSStatus SetListenerPosition(Float32 inX, Float32 inY, Float32 inZ)
        {
            alListener3f(AL_POSITION, inX, inY, inZ);
            return alGetError();
        }
        
        OSStatus SetListenerGain(Float32 inValue)
        {
            alListenerf(AL_GAIN, inValue);
            return alGetError();
        }
        
        OSStatus SetMaxDistance(Float32 inValue)
        {
            OSStatus result = 0;
            for (UInt32 i=0; i < mEffectsMap->Size(); i++)
            {
                SoundEngineEffect *theEffect = mEffectsMap->GetEffectByIndex(i);
                if ((result = theEffect->SetMaxDistance(inValue)) != AL_NO_ERROR)
                    return result;
            }
            return result;			
        }
        
        OSStatus SetReferenceDistance(Float32 inValue)
        {
            OSStatus result = 0;
            for (UInt32 i=0; i < mEffectsMap->Size(); i++)
            {
                SoundEngineEffect *theEffect = mEffectsMap->GetEffectByIndex(i);
                if ((result = theEffect->SetReferenceDistance(inValue)) != AL_NO_ERROR)
                    return result;
            }
            return result;	
        }
        
        OSStatus SetEffectsVolume(Float32 inValue)
        {
            OSStatus result = 0;
            for (UInt32 i=0; i < mEffectsMap->Size(); i++)
            {
                SoundEngineEffect *theEffect = mEffectsMap->GetEffectByIndex(i);
                if ((result = theEffect->SetLevel(inValue)) != AL_NO_ERROR)
                    return result;
            }
            return result;	
        }
        
        OSStatus UpdateGain()
        {
            return SetEffectsVolume(mGain);
        }
        
        OSStatus LoadEffect(const char *inFilePath, UInt32 *outEffectID)
        {
            SoundEngineEffect *theEffect = new SoundEngineEffect(inFilePath, NULL, NULL, false);
            OSStatus result = theEffect->AttachFilesToSource();
            if (result == noErr)
            {
                *outEffectID = theEffect->GetEffectID();
                mEffectsMap->Add(*outEffectID, &theEffect);
            }
            return result;
        }
        
        OSStatus LoadLoopingEffect(const char *inLoopFilePath, const char *inAttackFilePath, const char *inDecayFilePath, UInt32 *outEffectID)
        {
            SoundEngineEffect *theEffect = new SoundEngineEffect(inLoopFilePath, inAttackFilePath, inDecayFilePath, true);
            OSStatus result = theEffect->AttachFilesToSource();
            if (result == noErr)
            {
                *outEffectID = theEffect->GetEffectID();
                mEffectsMap->Add(*outEffectID, &theEffect);
            }
            return result;
        }
        
        OSStatus UnloadEffect(UInt32 inEffectID)
        {
            mEffectsMap->Remove(inEffectID);
            return 0;
        }
        
        OSStatus StartEffect(UInt32 inEffectID)
        {
            SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
            return (theEffect) ? theEffect->Start() : kSoundEngineErrInvalidID;
        }
        
        OSStatus StopEffect(UInt32 inEffectID, Boolean inDoDecay)
        {
            SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
            return (theEffect) ? theEffect->Stop(inDoDecay) : kSoundEngineErrInvalidID;
        }
        
        OSStatus SetEffectPitch(UInt32 inEffectID, Float32 inValue)
        {
            SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
            return (theEffect) ? theEffect->SetPitch(inValue) : kSoundEngineErrInvalidID;			
        }
        
        OSStatus SetEffectVolume(UInt32 inEffectID, Float32 inValue)
        {
            SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
            return (theEffect) ?  theEffect->SetLevel(inValue) : kSoundEngineErrInvalidID;
        }
        
        OSStatus	SetEffectPosition(UInt32 inEffectID, Float32 inX, Float32 inY, Float32 inZ)	
        {
            SoundEngineEffect *theEffect = mEffectsMap->Get(inEffectID);
            return (theEffect) ? theEffect->SetPosition(inX, inY, inZ) : kSoundEngineErrInvalidID;
        }
        
    private:
        Float32									mOutputRate;
        Float32									mGain;
        ALCcontext*								mContext;
        ALCdevice*								mDevice;
        SoundEngineEffectMap*					mEffectsMap;
    };

#pragma mark ***** API *****
//==================================================================================================
//	Sound Engine
//==================================================================================================

extern "C"
OSStatus  SoundEngine_Initialize(Float32 inMixerOutputRate)
{
    if (sOpenALObject)
        delete sOpenALObject;
    
    if (sBackgroundTrackMgr)
        delete sBackgroundTrackMgr;
    
    AudioSessionInitialize(nil, nil, nil, nil);
    
    UInt32 sessionCategory = kAudioSessionCategory_AmbientSound;
    AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(sessionCategory), &sessionCategory);
    
    AudioSessionSetActive(true);		
    
    sOpenALObject = new OpenALObject(inMixerOutputRate);	
    sBackgroundTrackMgr = new BackgroundTrackMgr();
    
    return sOpenALObject->Initialize();
    
}

extern "C"
OSStatus  SoundEngine_Teardown()
{
    if (sOpenALObject)
    {
        delete sOpenALObject;
        sOpenALObject = NULL;
    }
    
    if (sBackgroundTrackMgr)
    {
        delete sBackgroundTrackMgr;
        sBackgroundTrackMgr = NULL;	
    }
    
    return 0; 
}

extern "C"
OSStatus  SoundEngine_SetMasterVolume(Float32 inValue)
{
    OSStatus result = noErr;
    gMasterVolumeGain = inValue;
    if (sBackgroundTrackMgr)
        result = sBackgroundTrackMgr->UpdateGain();
    
    if (result) return result;
    
    if (sOpenALObject) 
        return sOpenALObject->UpdateGain();
    
    return result;
}

extern "C"
OSStatus  SoundEngine_SetListenerPosition(Float32 inX, Float32 inY, Float32 inZ)
{	
    return (sOpenALObject) ? sOpenALObject->SetListenerPosition(inX, inY, inZ) : kSoundEngineErrUnitialized;
}

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

extern "C"
OSStatus  SoundEngine_LoadBackgroundMusicTrack(const char* inPath, Boolean inAddToQueue, Boolean inLoadAtOnce)
{
    if (sBackgroundTrackMgr == NULL)
        sBackgroundTrackMgr = new BackgroundTrackMgr();
    return sBackgroundTrackMgr->LoadTrack(inPath, inAddToQueue, inLoadAtOnce);
}

extern "C"
OSStatus  SoundEngine_UnloadBackgroundMusicTrack()
{
    if (sBackgroundTrackMgr)
    {
        delete sBackgroundTrackMgr;
        sBackgroundTrackMgr = NULL;
    }
    
    return 0;
}

extern "C"
OSStatus  SoundEngine_StartBackgroundMusic()
{
    return (sBackgroundTrackMgr) ? sBackgroundTrackMgr->Start() : kSoundEngineErrUnitialized;
}

extern "C"
OSStatus  SoundEngine_StopBackgroundMusic(Boolean stopAtEnd)
{
    return (sBackgroundTrackMgr) ?  sBackgroundTrackMgr->Stop(stopAtEnd) : kSoundEngineErrUnitialized;
}

extern "C"
OSStatus  SoundEngine_SetBackgroundMusicVolume(Float32 inValue)
{
    return (sBackgroundTrackMgr) ? sBackgroundTrackMgr->SetVolume(inValue) : kSoundEngineErrUnitialized;
}

extern "C"
bool LoadSoundFile(const char *inFilePath, UInt32 *outEffectID)
{
    SoundEngineEffect *theEffect = new SoundEngineEffect(inFilePath, NULL, NULL, false);
    OSStatus result = theEffect->AttachFilesToSource();
    if (result == noErr)
    {
        //-Mat getEffectID() returns sourceID, but we want the genBuffer ID that was done last (mAttackBufferID), I have no idea
        //what SourceID is used for, but it's not the sound buffer, anyhow, the buffer after mSourceID is the one we want so +1
        *outEffectID = theEffect->GetEffectID()+1;
    }
    return (result == noErr);
}
    
}//namespace SoundEngine