audio_mixer.h

/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef BLADERUNNER_AUDIO_MIXER_H
#define BLADERUNNER_AUDIO_MIXER_H

#include "audio/audiostream.h"
#include "audio/mixer.h"

#include "common/mutex.h"

#include "bladerunner/bladerunner.h" // For BLADERUNNER_ORIGINAL_BUGS symbol

namespace BladeRunner {

class BladeRunnerEngine;

#if !BLADERUNNER_ORIGINAL_BUGS
enum audioMixerAppTimers {
    kAudioMixerAppTimerMusicNext    =  0,
    kAudioMixerAppTimerMusicFadeOut =  1
};
#endif

class AudioMixer {
#if BLADERUNNER_ORIGINAL_BUGS
    static const int kChannels         = 9;
    static const int kUsableChannels   = 8;
    static const int kMusicChannel     = 8;
#else
    static const int kChannels         = 15;
    static const int kUsableChannels   = 14;
    static const int kMusicChannel     = 14;

    static const int kAudioMixerAppTimersNum = 2;
#endif // BLADERUNNER_ORIGINAL_BUGS
    static const int kUpdatesPerSecond = 40;

    struct Channel {
        bool                isPresent;
        int                 priority;
        bool                loop;
        Audio::SoundHandle  handle;
        Audio::AudioStream *stream;
        float               volume;       // should be in [0.0f, 100.0f]. It's percent for the Audio::Mixer::kMaxChannelVolume
        float               volumeDelta;
        float               volumeTarget; // should be in [0.0f, 100.0f], as for volume field.
        float               pan;          // should be in [-100.0f, 100.0f]. It's percent for 127 (max absolute balance value)
        float               panDelta;
        float               panTarget;    // should be in [-100.0f, 100.0f], as for pan field.
        void              (*endCallback)(int channel, void *data);
        void               *callbackData;
        uint32              timeStarted;
        uint32              trackDurationMs;
        bool                sentToMixer;
    };

    BladeRunnerEngine *_vm;

    Channel       _channels[kChannels];
    Common::Mutex _mutex;

#if !BLADERUNNER_ORIGINAL_BUGS
    struct audioMixerAppTimer {
        bool                started;
        uint32              intervalMillis; // expiration interval in milliseconds
        uint32              lastFired;      // time of last time the timer expired in milliseconds
    };

    audioMixerAppTimer      _audioMixerAppTimers[kAudioMixerAppTimersNum];
#endif // !BLADERUNNER_ORIGINAL_BUGS

public:
    AudioMixer(BladeRunnerEngine *vm);
    ~AudioMixer();

    int play(Audio::Mixer::SoundType type, Audio::RewindableAudioStream *stream, int priority, bool loop, int volume, int pan, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);
    int playMusic(Audio::RewindableAudioStream *stream, int volume, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);
    void stop(int channel, uint32 time);

    void adjustVolume(int channel, int targetVolume, uint32 time);
    void adjustPan(int channel, int targetPan, uint32 time);

#if !BLADERUNNER_ORIGINAL_BUGS
    void startAppTimerProc(int audioMixAppTimerId, uint32 intervalMillis);
    void stopAppTimerProc(int audioMixAppTimerId);
#endif // !BLADERUNNER_ORIGINAL_BUGS
    // TODO Are these completely unused?
//  void resume(int channel, uint32 delay);
//  void pause(int channel, uint32 delay);

private:
    int playInChannel(int channel, Audio::Mixer::SoundType type, Audio::RewindableAudioStream *stream, int priority, bool loop, int volume, int pan, void(*endCallback)(int, void *), void *callbackData, uint32 trackDurationMs);

    bool isActive(int channel) const;
    void tick();
    static void timerCallback(void *refCon);
};

} // End of namespace BladeRunner

#endif