soundengine.cpp

在iPhone OS上使用用Objective-C语言开发的Demo程序

				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;
			}
			return AudioQueueStart(mQueue, NULL);
		}
		
		OSStatus Stop(Boolean inStopAtEnd)
		{
			if (inStopAtEnd)
			{
				mStopAtEnd = true;
				return noErr;
			}
			else
				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) {