Aegisub/src/audio_player_openal.h

// Copyright (c) 2007, Niels Martin Hansen
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
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// Aegisub Project http://www.aegisub.org/

/// @file audio_player_openal.h
/// @see audio_player_openal.cpp
/// @ingroup audio_output
///

#ifdef WITH_OPENAL
#include "include/aegisub/audio_player.h"
#include "include/aegisub/audio_provider.h"

#ifdef __WINDOWS__
#include <al.h>
#include <alc.h>
#elif defined(__APPLE__)
#include <OpenAL/al.h>
#include <OpenAL/alc.h>
#else
#include <AL/al.h>
#include <AL/alc.h>
#endif

#include <vector>

#include <wx/timer.h>

class OpenALPlayer : public AudioPlayer, wxTimer {
	/// Number of OpenAL buffers to use
	static const ALsizei num_buffers = 8;

	bool playing = false; ///< Is audio currently playing?

	float volume = 1.f; ///< Current audio volume
	ALsizei samplerate; ///< Sample rate of the audio
	int bpf; ///< Bytes per frame

	int64_t start_frame = 0; ///< First frame of playbacka
	int64_t cur_frame = 0; ///< Next frame to write to playback buffers
	int64_t end_frame = 0; ///< Last frame to play

	ALCdevice *device = nullptr; ///< OpenAL device handle
	ALCcontext *context = nullptr; ///< OpenAL sound context
	ALuint buffers[num_buffers]; ///< OpenAL sound buffers
	ALuint source = 0; ///< OpenAL playback source

	/// Index into buffers, first free (unqueued) buffer to be filled
	ALsizei buf_first_free = 0;

	/// Index into buffers, first queued (non-free) buffer
	ALsizei buf_first_queued = 0;

	/// Number of free buffers
	ALsizei buffers_free = 0;

	/// Number of buffers which have been fully played since playback was last started
	ALsizei buffers_played = 0;

	wxStopWatch playback_segment_timer;

	/// Buffer to decode audio into
	std::vector<char> decode_buffer;

	/// Fill count OpenAL buffers
	void FillBuffers(ALsizei count);

protected:
	/// wxTimer override to periodically fill available buffers
	void Notify() override;

public:
	OpenALPlayer(AudioProvider *provider);
	~OpenALPlayer();

	void Play(int64_t start,int64_t count) override;
	void Stop() override;
	bool IsPlaying() override { return playing; }

	int64_t GetEndPosition() override { return end_frame; }
	int64_t GetCurrentPosition() override;
	void SetEndPosition(int64_t pos) override;

	void SetVolume(double vol) override { volume = vol; }
};
#endif