soundengine.h

在iPhone OS上使用用Objective-C语言开发的Demo程序

/*

===== IMPORTANT =====

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Although this sample code has been reviewed for technical accuracy, it is not
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=====================

File: SoundEngine.h
Abstract: These functions play background music tracks, multiple sound effects,
and support stereo panning with a low-latency response.

Version: 1.6

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*/

/*==================================================================================================
	SoundEngine.h
==================================================================================================*/
#if !defined(__SoundEngine_h__)
#define __SoundEngine_h__

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

//	System Includes
#include <CoreAudio/CoreAudioTypes.h>
#include <AudioToolbox/AudioToolbox.h>

#if defined(__cplusplus)
extern "C"
{
#endif

//==================================================================================================
//	Sound Engine
//==================================================================================================
/*!
    @enum SoundEngine error codes
    @abstract   These are the error codes returned from the SoundEngine API.
    @constant   kSoundEngineErrUnitialized 
		The SoundEngine has not been initialized. Use SoundEngine_Initialize().
    @constant   kSoundEngineErrInvalidID 
		The specified EffectID was not found. This can occur if the effect has not been loaded, or
		if an unloaded is trying to be accessed.
    @constant   kSoundEngineErrFileNotFound 
		The specified file was not found.
    @constant   kSoundEngineErrInvalidFileFormat 
		The format of the file is invalid. Effect data must be little-endian 8 or 16 bit LPCM.
    @constant   kSoundEngineErrDeviceNotFound 
		The output device was not found.

*/
enum {
		kSoundEngineErrUnitialized			= 1,
		kSoundEngineErrInvalidID			= 2,
		kSoundEngineErrFileNotFound			= 3,
		kSoundEngineErrInvalidFileFormat	= 4,
		kSoundEngineErrDeviceNotFound		= 5
};


/*!
    @function       SoundEngine_Initialize
    @abstract       Initializes and sets up the sound engine. Calling after a previous initialize will
						reset the state of the SoundEngine, with all previous effects and music tracks
						erased. Note: This is not required, loading an effect or background track will 
						initialize as necessary.
    @param          inMixerOutputRate
                        A Float32 that represents the output sample rate of the mixer unit. Setting this to 
						0 will use the default rate (the sample rate of the device)
	@result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_Initialize(Float32 inMixerOutputRate);

/*!
    @function       SoundEngine_Teardown
    @abstract       Tearsdown the sound engine.
    @result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_Teardown();

/*!
    @function       SoundEngine_SetMasterVolume
    @abstract       Sets the overall volume of all sounds coming from the process
    @param          inValue
                        A Float32 that represents the level. The range is between 0.0 and 1.0 (inclusive).
    @result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_SetMasterVolume(Float32 inValue);

/*!
    @function       SoundEngine_SetListenerPosition
    @abstract       Sets the position of the listener in the 3D space
    @param          inX
                        A Float32 that represents the listener's position along the X axis.
    @param          inY
                        A Float32 that represents the listener's position along the Y axis.
    @param          inZ
                        A Float32 that represents the listener's position along the Z axis.
    @result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_SetListenerPosition(Float32 inX, Float32 inY, Float32 inZ);

/*!
    @function       SoundEngine_SetListenerGain
    @abstract       Sets the gain of the listener. Must be >= 0.0
    @param          inValue
                        A Float32 that represents the listener's gain
    @result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_SetListenerGain(Float32 inValue);

/*!
    @function       SoundEngine_LoadBackgroundMusicTrack
    @abstract       Tells the background music player which file to play
    @param          inPath
                        The absolute path to the file to play.
    @param          inAddToQueue
                        If true, file will be added to the current background music queue. If
						false, queue will be cleared and only loop the specified file.
    @param          inLoadAtOnce
                        If true, file will be loaded completely into memory. If false, data will be 
						streamed from the file as needed. For games without large memory pressure and/or
						small background music files, this can save memory access and improve power efficiency
	@result         A OSStatus indicating success or failure.
*/
OSStatus  SoundEngine_LoadBackgroundMusicTrack(const char* inPath, Boolean inAddToQueue, Boolean inLoadAtOnce);

/*!
    @function       SoundEngine_UnloadBackgroundMusicTrack
    @abstract       Tells the background music player to release all resources and stop playing.