Audio::Mixer Class Reference

#include <mixer.h>

Inheritance diagram for Audio::Mixer:

Public Types
enum	SoundType { kPlainSoundType = 0, kMusicSoundType = 1, kSFXSoundType = 2, kSpeechSoundType = 3 }
enum	{ kMaxChannelVolume = 255, kMaxMixerVolume = 256 }

Public Member Functions
virtual bool	isReady () const =0
virtual Common::Mutex &	mutex ()=0
virtual void	playStream (SoundType type, SoundHandle *handle, AudioStream *stream, int id=-1, byte volume=kMaxChannelVolume, int8 balance=0, DisposeAfterUse::Flag autofreeStream=DisposeAfterUse::YES, bool permanent=false, bool reverseStereo=false)=0
virtual void	stopAll ()=0
virtual void	stopID (int id)=0
virtual void	stopHandle (SoundHandle handle)=0
virtual void	pauseAll (bool paused)=0
virtual void	pauseID (int id, bool paused)=0
virtual void	pauseHandle (SoundHandle handle, bool paused)=0
virtual bool	isSoundIDActive (int id)=0
virtual int	getSoundID (SoundHandle handle)=0
virtual bool	isSoundHandleActive (SoundHandle handle)=0
virtual void	muteSoundType (SoundType type, bool mute)=0
virtual bool	isSoundTypeMuted (SoundType type) const =0
virtual void	setChannelVolume (SoundHandle handle, byte volume)=0
virtual byte	getChannelVolume (SoundHandle handle)=0
virtual void	setChannelBalance (SoundHandle handle, int8 balance)=0
virtual int8	getChannelBalance (SoundHandle handle)=0
virtual void	setChannelRate (SoundHandle handle, uint32 rate)=0
virtual uint32	getChannelRate (SoundHandle handle)=0
virtual void	resetChannelRate (SoundHandle handle)=0
virtual uint32	getSoundElapsedTime (SoundHandle handle)=0
virtual Timestamp	getElapsedTime (SoundHandle handle)=0
virtual void	loopChannel (SoundHandle handle)=0
virtual bool	hasActiveChannelOfType (SoundType type)=0
virtual void	setVolumeForSoundType (SoundType type, int volume)=0
virtual int	getVolumeForSoundType (SoundType type) const =0
virtual uint	getOutputRate () const =0
virtual bool	getOutputStereo () const =0
virtual uint	getOutputBufSize () const =0

Detailed Description

The main audio mixer that handles mixing of an arbitrary number of audio streams (in the form of AudioStream instances).

Member Enumeration Documentation

SoundType

enum Audio::Mixer::SoundType

Sound types.

Enumerator
kPlainSoundType	Plain sound.
kMusicSoundType	Music.
kSFXSoundType	Sound effects.
kSpeechSoundType	Speech.

anonymous enum

anonymous enum

Max volumes.

Enumerator
kMaxChannelVolume	Max channel volume.
kMaxMixerVolume	Max global volume.

Member Function Documentation

isReady()

virtual bool Audio::Mixer::isReady ( ) const

pure virtual

Check whether the mixer is ready and set up.

The mixer might not be set up on systems that do not support digital sound output. In such case, the mixer processing might never be called. That, in turn, can cause breakage in games that try to sync with an audio stream. In particular, the AdLib MIDI emulation.

Returns

Whether the mixer is ready and set up.

Implemented in Audio::MixerImpl.

mutex()

virtual Common::Mutex& Audio::Mixer::mutex ( )

pure virtual

Return the mixer's internal mutex so that audio players can use it.

Implemented in Audio::MixerImpl.

playStream()

virtual void Audio::Mixer::playStream ( SoundType  type, SoundHandle *  handle, AudioStream *  stream, int  id = -1, byte  volume = kMaxChannelVolume, int8  balance = 0, DisposeAfterUse::Flag  autofreeStream = DisposeAfterUse::YES, bool  permanent = false, bool  reverseStereo = false  )

pure virtual

Start playing the given audio stream.

Note that the sound ID assigned here is unique. At most, one stream with the given ID can play at any given time. Trying to play a sound with an ID that is already in use causes the new sound to not be played.

Parameters

type	Type of the stream - voice/SFX/music.
handle	A SoundHandle instance that can be used to reference and control the stream using suitable mixer methods.
stream	The actual AudioStream to be played.
id	Unique ID assigned to this stream.
volume	Volume with which to play the sound, ranging from 0 to 255.
balance	Balance with which to play the sound, ranging from -127 to 127 (full left to full right). 0 is balanced, -128 is invalid.
autofreeStream	If set, the stream will be freed after the playback is finished.
permanent	If set, a plain stopAll call will not stop this particular stream.
reverseStereo	If set, left and right channels will be swapped.

Implemented in Audio::MixerImpl.

stopAll()

virtual void Audio::Mixer::stopAll ( )

pure virtual

Stop all currently playing sounds.

Implemented in Audio::MixerImpl.

stopID()

virtual void Audio::Mixer::stopID ( int  id )

pure virtual

Stop playing the sound with the given ID.

Parameters

id	ID of the sound.

Implemented in Audio::MixerImpl.

stopHandle()

virtual void Audio::Mixer::stopHandle ( SoundHandle  handle )

pure virtual

Stop playing the sound corresponding to the given handle.

Parameters

handle

The sound to stop playing.

Implemented in Audio::MixerImpl.

pauseAll()

virtual void Audio::Mixer::pauseAll ( bool  paused )

pure virtual

Pause or unpause all sounds, including all regular and permanent channels.

Parameters

paused

True to pause everything, false to unpause.

Implemented in Audio::MixerImpl.

pauseID()

virtual void Audio::Mixer::pauseID ( int  id, bool  paused  )

pure virtual

Pause or unpause the sound with the given ID.

Parameters

id	ID of the sound.
paused	True to pause the sound, false to unpause it.

Implemented in Audio::MixerImpl.

pauseHandle()

virtual void Audio::Mixer::pauseHandle ( SoundHandle  handle, bool  paused  )

pure virtual

Pause or unpause the sound corresponding to the given handle.

Parameters

handle	The sound to pause or unpause.
paused	True to pause the sound, false to unpause it.

Implemented in Audio::MixerImpl.

isSoundIDActive()

virtual bool Audio::Mixer::isSoundIDActive ( int  id )

pure virtual

Check whether a sound with the given ID is active.

Parameters

id	ID of the sound to query.

Returns

True if the sound is active.

Implemented in Audio::MixerImpl.

getSoundID()

virtual int Audio::Mixer::getSoundID ( SoundHandle  handle )

pure virtual

Get the sound ID for the given handle.

Parameters

handle

The sound to query.

Returns

Sound ID if the sound is active.

Implemented in Audio::MixerImpl.

isSoundHandleActive()

virtual bool Audio::Mixer::isSoundHandleActive ( SoundHandle  handle )

pure virtual

Check whether a sound with the given handle is active.

Parameters

handle

The sound to query.

Returns

True if the sound is active.

Implemented in Audio::MixerImpl.

muteSoundType()

virtual void Audio::Mixer::muteSoundType ( SoundType  type, bool  mute  )

pure virtual

Set the mute state for a given sound type.

Parameters

type	Sound type. See SoundType.
mute	Whether to mute (= true) or not (= false).

Implemented in Audio::MixerImpl.

isSoundTypeMuted()

virtual bool Audio::Mixer::isSoundTypeMuted ( SoundType  type ) const

pure virtual

Query the mute state for a given sound type.

Parameters

type	Sound type. See SoundType.

Implemented in Audio::MixerImpl.

setChannelVolume()

virtual void Audio::Mixer::setChannelVolume ( SoundHandle  handle, byte  volume  )

pure virtual

Set the channel volume for the given handle.

Parameters

handle	The sound to affect.
volume	The new channel volume, in the range 0 - kMaxChannelVolume.

Implemented in Audio::MixerImpl.

getChannelVolume()

virtual byte Audio::Mixer::getChannelVolume ( SoundHandle  handle )

pure virtual

Get the channel volume for the given handle.

Parameters

handle

The sound to affect.

Returns

The channel volume.

Implemented in Audio::MixerImpl.

setChannelBalance()

virtual void Audio::Mixer::setChannelBalance ( SoundHandle  handle, int8  balance  )

pure virtual

Set the channel balance for the given handle.

Parameters

handle	The sound to affect.
balance	The new channel balance: (-127 ... 0 ... 127) corresponds to (left ... center ... right)

Implemented in Audio::MixerImpl.

getChannelBalance()

virtual int8 Audio::Mixer::getChannelBalance ( SoundHandle  handle )

pure virtual

Get the channel balance for the given handle.

Parameters

handle

The sound to affect.

Returns

The channel balance.

Implemented in Audio::MixerImpl.

setChannelRate()

virtual void Audio::Mixer::setChannelRate ( SoundHandle  handle, uint32  rate  )

pure virtual

Set the sample rate for the given handle.

Parameters

handle	The sound to affect.
rate	The new sample rate. Must be less than 131072

Implemented in Audio::MixerImpl.

getChannelRate()

virtual uint32 Audio::Mixer::getChannelRate ( SoundHandle  handle )

pure virtual

Get the sample rate for the given handle.

Parameters

handle

The sound to affect.

Returns

The current sample rate of the channel.

Implemented in Audio::MixerImpl.

resetChannelRate()

virtual void Audio::Mixer::resetChannelRate ( SoundHandle  handle )

pure virtual

Reset the sample rate of the channel back to its AudioStream's native rate.

Parameters

handle

The sound to affect.

Implemented in Audio::MixerImpl.

getSoundElapsedTime()

virtual uint32 Audio::Mixer::getSoundElapsedTime ( SoundHandle  handle )

pure virtual

Get an approximation of for how long the channel has been playing.

Implemented in Audio::MixerImpl.

getElapsedTime()

virtual Timestamp Audio::Mixer::getElapsedTime ( SoundHandle  handle )

pure virtual

Get an approximation of for how long the channel has been playing.

Implemented in Audio::MixerImpl.

loopChannel()

virtual void Audio::Mixer::loopChannel ( SoundHandle  handle )

pure virtual

Replace the channel's stream with a version that loops indefinitely.

Implemented in Audio::MixerImpl.

hasActiveChannelOfType()

virtual bool Audio::Mixer::hasActiveChannelOfType ( SoundType  type )

pure virtual

Check whether any channel of the given sound type is active.

For example, this can be used to check whether any SFX sound is currently playing by checking for type kSFXSoundType.

Parameters

type	The sound type to query.

Returns

True if any channels of the specified type are active.

Implemented in Audio::MixerImpl.

setVolumeForSoundType()

virtual void Audio::Mixer::setVolumeForSoundType ( SoundType  type, int  volume  )

pure virtual

Set the volume for the given sound type.

Parameters

type	Sound type.
volume	The new global volume, in the range 0 - kMaxMixerVolume.

Implemented in Audio::MixerImpl.

getVolumeForSoundType()

virtual int Audio::Mixer::getVolumeForSoundType ( SoundType  type ) const

pure virtual

Check what the global volume is for a sound type.

Parameters

type	Sound type.

Returns

The global volume, in the range 0 - kMaxMixerVolume.

Implemented in Audio::MixerImpl.

getOutputRate()

virtual uint Audio::Mixer::getOutputRate ( ) const

pure virtual

Return the output sample rate of the system.

Returns

The output sample rate in Hz.

Implemented in Audio::MixerImpl.

getOutputStereo()

virtual bool Audio::Mixer::getOutputStereo ( ) const

pure virtual

Check whether the output is stereo.

Returns

true if output is stereo, false if not.

Implemented in Audio::MixerImpl.

getOutputBufSize()

virtual uint Audio::Mixer::getOutputBufSize ( ) const

pure virtual

Return the output sample buffer size of the system.

The return value is measured in frame units instead of bytes. It can be converted to bytes by multiplying it with the sample size and the number of channels. For example, for 16-bit stereo output it should be multiplied by 4.

Returns

The number of samples processed at each audio callback.

Implemented in Audio::MixerImpl.

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The documentation for this class was generated from the following file:

• audio/mixer.h