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Diffstat (limited to 'sound/mixer_intern.h')
| -rw-r--r-- | sound/mixer_intern.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/sound/mixer_intern.h b/sound/mixer_intern.h new file mode 100644 index 0000000000..46ba97e66c --- /dev/null +++ b/sound/mixer_intern.h @@ -0,0 +1,154 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + */ + +#ifndef SOUND_MIXER_INTERN_H +#define SOUND_MIXER_INTERN_H + +#include "common/scummsys.h" +#include "common/mutex.h" +#include "sound/mixer.h" + +namespace Audio { + +/** + * The (default) implementation of the ScummVM audio mixing subsystem. + * + * Backends are responsible for allocating (and later releasing) an instance + * of this class, which engines can access via OSystem::getMixer(). + * + * Initialisation of instances of this class usually happens as follows: + * 1) Creat a new Audio::MixerImpl instance. + * 2) Set the hardware output sample rate via the setSampleRate() method. + * 3) Hook up the mixCallback() in a suitable audio processing thread/callback. + * 4) Change the mixer into ready mode via setReady(true). + * 5) Start audio processing (e.g. by resuming the audio thread, if applicable). + * + * In the future, we might make it possible for backends to provide + * (partial) alternative implementations of the mixer, e.g. to make + * better use of native sound mixing support on low-end devices. + * + * @see OSystem::getMixer() + */ +class MixerImpl : public Mixer { +private: + enum { + NUM_CHANNELS = 16 + }; + + OSystem *_syst; + Common::Mutex _mutex; + + uint _sampleRate; + bool _mixerReady; + uint32 _handleSeed; + + int _volumeForSoundType[4]; + Channel *_channels[NUM_CHANNELS]; + + +public: + MixerImpl(OSystem *system); + ~MixerImpl(); + + virtual bool isReady() const { return _mixerReady; } + + virtual void playRaw( + SoundType type, + SoundHandle *handle, + void *sound, uint32 size, uint rate, byte flags, + int id = -1, byte volume = 255, int8 balance = 0, + uint32 loopStart = 0, uint32 loopEnd = 0); + + virtual void playInputStream( + SoundType type, + SoundHandle *handle, + AudioStream *input, + int id = -1, byte volume = 255, int8 balance = 0, + bool autofreeStream = true, + bool permanent = false, + bool reverseStereo = false); + + + + virtual void stopAll(); + virtual void stopID(int id); + virtual void stopHandle(SoundHandle handle); + + virtual void pauseAll(bool paused); + virtual void pauseID(int id, bool paused); + virtual void pauseHandle(SoundHandle handle, bool paused); + + virtual bool isSoundIDActive(int id); + virtual int getSoundID(SoundHandle handle); + + virtual bool isSoundHandleActive(SoundHandle handle); + + virtual void setChannelVolume(SoundHandle handle, byte volume); + virtual void setChannelBalance(SoundHandle handle, int8 balance); + + virtual uint32 getSoundElapsedTime(SoundHandle handle); + + virtual bool hasActiveChannelOfType(SoundType type); + + virtual void setVolumeForSoundType(SoundType type, int volume); + virtual int getVolumeForSoundType(SoundType type) const; + + virtual uint getOutputRate() const; + +protected: + void insertChannel(SoundHandle *handle, Channel *chan); + +public: + /** + * The mixer callback function, to be called at regular intervals by + * the backend (e.g. from an audio mixing thread). All the actual mixing + * work is done from here. + */ + void mixCallback(byte *samples, uint len); + + /** + * Set the internal 'is ready' flag of the mixer. + * Backends should invoke Mixer::setReady(true) once initialisation of + * their audio system has been completed (and in particular, *after* + * setOutputRate() has been called). + */ + void setReady(bool ready); + + /** + * Set the output sample rate. + * + * @param sampleRate the new output sample rate + * + * @note Right now, this can be done exactly ONCE. That is, the mixer + * currently does not support changing the output sample rate after it + * has been set for the first time. This may change in the future. + */ + void setOutputRate(uint sampleRate); +}; + + +} // End of namespace Audio + +#endif |