summaryrefslogtreecommitdiff
path: root/src/client/sound_openal.cpp
blob: f4e61f93e332610576de7b31dea786cd1caad8ec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
OpenAL support based on work by:
Copyright (C) 2011 Sebastian 'Bahamada' Rühl
Copyright (C) 2011 Cyriaque 'Cisoun' Skrapits <cysoun@gmail.com>
Copyright (C) 2011 Giuseppe Bilotta <giuseppe.bilotta@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; ifnot, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "sound_openal.h"

#if defined(_WIN32)
	#include <al.h>
	#include <alc.h>
	//#include <alext.h>
#elif defined(__APPLE__)
	#define OPENAL_DEPRECATED
	#include <OpenAL/al.h>
	#include <OpenAL/alc.h>
	//#include <OpenAL/alext.h>
#else
	#include <AL/al.h>
	#include <AL/alc.h>
	#include <AL/alext.h>
#endif
#include <cmath>
#include <vorbis/vorbisfile.h>
#include <cassert>
#include "log.h"
#include "util/numeric.h" // myrand()
#include "porting.h"
#include <vector>
#include <fstream>
#include <unordered_map>
#include <unordered_set>

#define BUFFER_SIZE 30000

std::shared_ptr<SoundManagerSingleton> g_sound_manager_singleton;

typedef std::unique_ptr<ALCdevice, void (*)(ALCdevice *p)> unique_ptr_alcdevice;
typedef std::unique_ptr<ALCcontext, void(*)(ALCcontext *p)> unique_ptr_alccontext;

static void delete_alcdevice(ALCdevice *p)
{
	if (p)
		alcCloseDevice(p);
}

static void delete_alccontext(ALCcontext *p)
{
	if (p) {
		alcMakeContextCurrent(nullptr);
		alcDestroyContext(p);
	}
}

static const char *alErrorString(ALenum err)
{
	switch (err) {
	case AL_NO_ERROR:
		return "no error";
	case AL_INVALID_NAME:
		return "invalid name";
	case AL_INVALID_ENUM:
		return "invalid enum";
	case AL_INVALID_VALUE:
		return "invalid value";
	case AL_INVALID_OPERATION:
		return "invalid operation";
	case AL_OUT_OF_MEMORY:
		return "out of memory";
	default:
		return "<unknown OpenAL error>";
	}
}

static ALenum warn_if_error(ALenum err, const char *desc)
{
	if(err == AL_NO_ERROR)
		return err;
	warningstream<<desc<<": "<<alErrorString(err)<<std::endl;
	return err;
}

void f3_set(ALfloat *f3, v3f v)
{
	f3[0] = v.X;
	f3[1] = v.Y;
	f3[2] = v.Z;
}

struct SoundBuffer
{
	ALenum format;
	ALsizei freq;
	ALuint buffer_id;
	std::vector<char> buffer;
};

SoundBuffer *load_opened_ogg_file(OggVorbis_File *oggFile,
		const std::string &filename_for_logging)
{
	int endian = 0; // 0 for Little-Endian, 1 for Big-Endian
	int bitStream;
	long bytes;
	char array[BUFFER_SIZE]; // Local fixed size array
	vorbis_info *pInfo;

	SoundBuffer *snd = new SoundBuffer;

	// Get some information about the OGG file
	pInfo = ov_info(oggFile, -1);

	// Check the number of channels... always use 16-bit samples
	if(pInfo->channels == 1)
		snd->format = AL_FORMAT_MONO16;
	else
		snd->format = AL_FORMAT_STEREO16;

	// The frequency of the sampling rate
	snd->freq = pInfo->rate;

	// Keep reading until all is read
	do
	{
		// Read up to a buffer's worth of decoded sound data
		bytes = ov_read(oggFile, array, BUFFER_SIZE, endian, 2, 1, &bitStream);

		if(bytes < 0)
		{
			ov_clear(oggFile);
			infostream << "Audio: Error decoding "
				<< filename_for_logging << std::endl;
			delete snd;
			return nullptr;
		}

		// Append to end of buffer
		snd->buffer.insert(snd->buffer.end(), array, array + bytes);
	} while (bytes > 0);

	alGenBuffers(1, &snd->buffer_id);
	alBufferData(snd->buffer_id, snd->format,
			&(snd->buffer[0]), snd->buffer.size(),
			snd->freq);

	ALenum error = alGetError();

	if(error != AL_NO_ERROR){
		infostream << "Audio: OpenAL error: " << alErrorString(error)
				<< "preparing sound buffer" << std::endl;
	}

	//infostream << "Audio file "
	//	<< filename_for_logging << " loaded" << std::endl;

	// Clean up!
	ov_clear(oggFile);

	return snd;
}

SoundBuffer *load_ogg_from_file(const std::string &path)
{
	OggVorbis_File oggFile;

	// Try opening the given file.
	// This requires libvorbis >= 1.3.2, as
	// previous versions expect a non-const char *
	if (ov_fopen(path.c_str(), &oggFile) != 0) {
		infostream << "Audio: Error opening " << path
			<< " for decoding" << std::endl;
		return nullptr;
	}

	return load_opened_ogg_file(&oggFile, path);
}

struct BufferSource {
	const char *buf;
	size_t cur_offset;
	size_t len;
};

size_t buffer_sound_read_func(void *ptr, size_t size, size_t nmemb, void *datasource)
{
	BufferSource *s = (BufferSource *)datasource;
	size_t copied_size = MYMIN(s->len - s->cur_offset, size);
	memcpy(ptr, s->buf + s->cur_offset, copied_size);
	s->cur_offset += copied_size;
	return copied_size;
}

int buffer_sound_seek_func(void *datasource, ogg_int64_t offset, int whence)
{
	BufferSource *s = (BufferSource *)datasource;
	if (whence == SEEK_SET) {
		if (offset < 0 || (size_t)MYMAX(offset, 0) >= s->len) {
			// offset out of bounds
			return -1;
		}
		s->cur_offset = offset;
		return 0;
	} else if (whence == SEEK_CUR) {
		if ((size_t)MYMIN(-offset, 0) > s->cur_offset
				|| s->cur_offset + offset > s->len) {
			// offset out of bounds
			return -1;
		}
		s->cur_offset += offset;
		return 0;
	}
	// invalid whence param (SEEK_END doesn't have to be supported)
	return -1;
}

long BufferSourceell_func(void *datasource)
{
	BufferSource *s = (BufferSource *)datasource;
	return s->cur_offset;
}

static ov_callbacks g_buffer_ov_callbacks = {
	&buffer_sound_read_func,
	&buffer_sound_seek_func,
	nullptr,
	&BufferSourceell_func
};

SoundBuffer *load_ogg_from_buffer(const std::string &buf, const std::string &id_for_log)
{
	OggVorbis_File oggFile;

	BufferSource s;
	s.buf = buf.c_str();
	s.cur_offset = 0;
	s.len = buf.size();

	if (ov_open_callbacks(&s, &oggFile, nullptr, 0, g_buffer_ov_callbacks) != 0) {
		infostream << "Audio: Error opening " << id_for_log
			<< " for decoding" << std::endl;
		return nullptr;
	}

	return load_opened_ogg_file(&oggFile, id_for_log);
}

struct PlayingSound
{
	ALuint source_id;
	bool loop;
};

class SoundManagerSingleton
{
public:
	unique_ptr_alcdevice  m_device;
	unique_ptr_alccontext m_context;
public:
	SoundManagerSingleton() :
		m_device(nullptr, delete_alcdevice),
		m_context(nullptr, delete_alccontext)
	{
	}

	bool init()
	{
		if (!(m_device = unique_ptr_alcdevice(alcOpenDevice(nullptr), delete_alcdevice))) {
			errorstream << "Audio: Global Initialization: Failed to open device" << std::endl;
			return false;
		}

		if (!(m_context = unique_ptr_alccontext(
				alcCreateContext(m_device.get(), nullptr), delete_alccontext))) {
			errorstream << "Audio: Global Initialization: Failed to create context" << std::endl;
			return false;
		}

		if (!alcMakeContextCurrent(m_context.get())) {
			errorstream << "Audio: Global Initialization: Failed to make current context" << std::endl;
			return false;
		}

		alDistanceModel(AL_INVERSE_DISTANCE_CLAMPED);

		if (alGetError() != AL_NO_ERROR) {
			errorstream << "Audio: Global Initialization: OpenAL Error " << alGetError() << std::endl;
			return false;
		}

		infostream << "Audio: Global Initialized: OpenAL " << alGetString(AL_VERSION)
			<< ", using " << alcGetString(m_device.get(), ALC_DEVICE_SPECIFIER)
			<< std::endl;

		return true;
	}

	~SoundManagerSingleton()
	{
		infostream << "Audio: Global Deinitialized." << std::endl;
	}
};

class OpenALSoundManager: public ISoundManager
{
private:
	OnDemandSoundFetcher *m_fetcher;
	ALCdevice *m_device;
	ALCcontext *m_context;
	int m_next_id;
	std::unordered_map<std::string, std::vector<SoundBuffer*>> m_buffers;
	std::unordered_map<int, PlayingSound*> m_sounds_playing;
	struct FadeState {
		FadeState() = default;

		FadeState(float step, float current_gain, float target_gain):
			step(step),
			current_gain(current_gain),
			target_gain(target_gain) {}
		float step;
		float current_gain;
		float target_gain;
	};

	std::unordered_map<int, FadeState> m_sounds_fading;
public:
	OpenALSoundManager(SoundManagerSingleton *smg, OnDemandSoundFetcher *fetcher):
		m_fetcher(fetcher),
		m_device(smg->m_device.get()),
		m_context(smg->m_context.get()),
		m_next_id(1)
	{
		infostream << "Audio: Initialized: OpenAL " << std::endl;
	}

	~OpenALSoundManager()
	{
		infostream << "Audio: Deinitializing..." << std::endl;

		std::unordered_set<int> source_del_list;

		for (const auto &sp : m_sounds_playing)
			source_del_list.insert(sp.first);

		for (const auto &id : source_del_list)
			deleteSound(id);

		for (auto &buffer : m_buffers) {
			for (SoundBuffer *sb : buffer.second) {
				delete sb;
			}
			buffer.second.clear();
		}
		m_buffers.clear();

		infostream << "Audio: Deinitialized." << std::endl;
	}

	void step(float dtime)
	{
		doFades(dtime);
	}

	void addBuffer(const std::string &name, SoundBuffer *buf)
	{
		std::unordered_map<std::string, std::vector<SoundBuffer*>>::iterator i =
				m_buffers.find(name);
		if(i != m_buffers.end()){
			i->second.push_back(buf);
			return;
		}
		std::vector<SoundBuffer*> bufs;
		bufs.push_back(buf);
		m_buffers[name] = bufs;
	}

	SoundBuffer* getBuffer(const std::string &name)
	{
		std::unordered_map<std::string, std::vector<SoundBuffer*>>::iterator i =
				m_buffers.find(name);
		if(i == m_buffers.end())
			return nullptr;
		std::vector<SoundBuffer*> &bufs = i->second;
		int j = myrand() % bufs.size();
		return bufs[j];
	}

	PlayingSound* createPlayingSound(SoundBuffer *buf, bool loop,
			float volume, float pitch)
	{
		infostream << "OpenALSoundManager: Creating playing sound" << std::endl;
		assert(buf);
		PlayingSound *sound = new PlayingSound;
		assert(sound);
		warn_if_error(alGetError(), "before createPlayingSound");
		alGenSources(1, &sound->source_id);
		alSourcei(sound->source_id, AL_BUFFER, buf->buffer_id);
		alSourcei(sound->source_id, AL_SOURCE_RELATIVE, true);
		alSource3f(sound->source_id, AL_POSITION, 0, 0, 0);
		alSource3f(sound->source_id, AL_VELOCITY, 0, 0, 0);
		alSourcei(sound->source_id, AL_LOOPING, loop ? AL_TRUE : AL_FALSE);
		volume = std::fmax(0.0f, volume);
		alSourcef(sound->source_id, AL_GAIN, volume);
		alSourcef(sound->source_id, AL_PITCH, pitch);
		alSourcePlay(sound->source_id);
		warn_if_error(alGetError(), "createPlayingSound");
		return sound;
	}

	PlayingSound* createPlayingSoundAt(SoundBuffer *buf, bool loop,
			float volume, v3f pos, float pitch)
	{
		infostream << "OpenALSoundManager: Creating positional playing sound"
				<< std::endl;
		assert(buf);
		PlayingSound *sound = new PlayingSound;
		assert(sound);
		warn_if_error(alGetError(), "before createPlayingSoundAt");
		alGenSources(1, &sound->source_id);
		alSourcei(sound->source_id, AL_BUFFER, buf->buffer_id);
		alSourcei(sound->source_id, AL_SOURCE_RELATIVE, false);
		alSource3f(sound->source_id, AL_POSITION, pos.X, pos.Y, pos.Z);
		alSource3f(sound->source_id, AL_VELOCITY, 0, 0, 0);
		// Use alDistanceModel(AL_INVERSE_DISTANCE_CLAMPED) and set reference
		// distance to clamp gain at <1 node distance, to avoid excessive
		// volume when closer
		alSourcef(sound->source_id, AL_REFERENCE_DISTANCE, 10.0f);
		alSourcei(sound->source_id, AL_LOOPING, loop ? AL_TRUE : AL_FALSE);
		// Multiply by 3 to compensate for reducing AL_REFERENCE_DISTANCE from
		// the previous value of 30 to the new value of 10
		volume = std::fmax(0.0f, volume * 3.0f);
		alSourcef(sound->source_id, AL_GAIN, volume);
		alSourcef(sound->source_id, AL_PITCH, pitch);
		alSourcePlay(sound->source_id);
		warn_if_error(alGetError(), "createPlayingSoundAt");
		return sound;
	}

	int playSoundRaw(SoundBuffer *buf, bool loop, float volume, float pitch)
	{
		assert(buf);
		PlayingSound *sound = createPlayingSound(buf, loop, volume, pitch);
		if(!sound)
			return -1;
		int id = m_next_id++;
		m_sounds_playing[id] = sound;
		return id;
	}

	int playSoundRawAt(SoundBuffer *buf, bool loop, float volume, const v3f &pos,
			float pitch)
	{
		assert(buf);
		PlayingSound *sound = createPlayingSoundAt(buf, loop, volume, pos, pitch);
		if(!sound)
			return -1;
		int id = m_next_id++;
		m_sounds_playing[id] = sound;
		return id;
	}

	void deleteSound(int id)
	{
		std::unordered_map<int, PlayingSound*>::iterator i = m_sounds_playing.find(id);
		if(i == m_sounds_playing.end())
			return;
		PlayingSound *sound = i->second;

		alDeleteSources(1, &sound->source_id);

		delete sound;
		m_sounds_playing.erase(id);
	}

	/* If buffer does not exist, consult the fetcher */
	SoundBuffer* getFetchBuffer(const std::string &name)
	{
		SoundBuffer *buf = getBuffer(name);
		if(buf)
			return buf;
		if(!m_fetcher)
			return nullptr;
		std::set<std::string> paths;
		std::set<std::string> datas;
		m_fetcher->fetchSounds(name, paths, datas);
		for (const std::string &path : paths) {
			loadSoundFile(name, path);
		}
		for (const std::string &data : datas) {
			loadSoundData(name, data);
		}
		return getBuffer(name);
	}

	// Remove stopped sounds
	void maintain()
	{
		if (!m_sounds_playing.empty()) {
			verbosestream << "OpenALSoundManager::maintain(): "
					<< m_sounds_playing.size() <<" playing sounds, "
					<< m_buffers.size() <<" sound names loaded"<<std::endl;
		}
		std::unordered_set<int> del_list;
		for (const auto &sp : m_sounds_playing) {
			int id = sp.first;
			PlayingSound *sound = sp.second;
			// If not playing, remove it
			{
				ALint state;
				alGetSourcei(sound->source_id, AL_SOURCE_STATE, &state);
				if(state != AL_PLAYING){
					del_list.insert(id);
				}
			}
		}
		if(!del_list.empty())
			verbosestream<<"OpenALSoundManager::maintain(): deleting "
					<<del_list.size()<<" playing sounds"<<std::endl;
		for (int i : del_list) {
			deleteSound(i);
		}
	}

	/* Interface */

	bool loadSoundFile(const std::string &name,
			const std::string &filepath)
	{
		SoundBuffer *buf = load_ogg_from_file(filepath);
		if (buf)
			addBuffer(name, buf);
		return !!buf;
	}

	bool loadSoundData(const std::string &name,
			const std::string &filedata)
	{
		SoundBuffer *buf = load_ogg_from_buffer(filedata, name);
		if (buf)
			addBuffer(name, buf);
		return !!buf;
	}

	void updateListener(const v3f &pos, const v3f &vel, const v3f &at, const v3f &up)
	{
		alListener3f(AL_POSITION, pos.X, pos.Y, pos.Z);
		alListener3f(AL_VELOCITY, vel.X, vel.Y, vel.Z);
		ALfloat f[6];
		f3_set(f, at);
		f3_set(f+3, -up);
		alListenerfv(AL_ORIENTATION, f);
		warn_if_error(alGetError(), "updateListener");
	}

	void setListenerGain(float gain)
	{
		alListenerf(AL_GAIN, gain);
	}

	int playSound(const std::string &name, bool loop, float volume, float fade, float pitch)
	{
		maintain();
		if (name.empty())
			return 0;
		SoundBuffer *buf = getFetchBuffer(name);
		if(!buf){
			infostream << "OpenALSoundManager: \"" << name << "\" not found."
					<< std::endl;
			return -1;
		}
		int handle = -1;
		if (fade > 0) {
			handle = playSoundRaw(buf, loop, 0.0f, pitch);
			fadeSound(handle, fade, volume);
		} else {
			handle = playSoundRaw(buf, loop, volume, pitch);
		}
		return handle;
	}

	int playSoundAt(const std::string &name, bool loop, float volume, v3f pos, float pitch)
	{
		maintain();
		if (name.empty())
			return 0;
		SoundBuffer *buf = getFetchBuffer(name);
		if(!buf){
			infostream << "OpenALSoundManager: \"" << name << "\" not found."
					<< std::endl;
			return -1;
		}
		return playSoundRawAt(buf, loop, volume, pos, pitch);
	}

	void stopSound(int sound)
	{
		maintain();
		deleteSound(sound);
	}

	void fadeSound(int soundid, float step, float gain)
	{
		// Ignore the command if step isn't valid.
		if (step == 0)
			return;
		float current_gain = getSoundGain(soundid);
		step = gain - current_gain > 0 ? abs(step) : -abs(step);
		if (m_sounds_fading.find(soundid) != m_sounds_fading.end()) {
			auto current_fade = m_sounds_fading[soundid];
			// Do not replace the fade if it's equivalent.
			if (current_fade.target_gain == gain && current_fade.step == step)
				return;
			m_sounds_fading.erase(soundid);
		}
		gain = rangelim(gain, 0, 1);
		m_sounds_fading[soundid] = FadeState(step, current_gain, gain);
	}

	void doFades(float dtime)
	{
		for (auto i = m_sounds_fading.begin(); i != m_sounds_fading.end();) {
			FadeState& fade = i->second;
			assert(fade.step != 0);
			fade.current_gain += (fade.step * dtime);

			if (fade.step < 0.f)
				fade.current_gain = std::max(fade.current_gain, fade.target_gain);
			else
				fade.current_gain = std::min(fade.current_gain, fade.target_gain);

			if (fade.current_gain <= 0.f)
				stopSound(i->first);
			else
				updateSoundGain(i->first, fade.current_gain);

			// The increment must happen during the erase call, or else it'll segfault.
			if (fade.current_gain == fade.target_gain)
				m_sounds_fading.erase(i++);
			else
				i++;
		}
	}

	bool soundExists(int sound)
	{
		maintain();
		return (m_sounds_playing.count(sound) != 0);
	}

	void updateSoundPosition(int id, v3f pos)
	{
		auto i = m_sounds_playing.find(id);
		if (i == m_sounds_playing.end())
			return;
		PlayingSound *sound = i->second;

		alSourcei(sound->source_id, AL_SOURCE_RELATIVE, false);
		alSource3f(sound->source_id, AL_POSITION, pos.X, pos.Y, pos.Z);
		alSource3f(sound->source_id, AL_VELOCITY, 0, 0, 0);
		alSourcef(sound->source_id, AL_REFERENCE_DISTANCE, 30.0);
	}

	bool updateSoundGain(int id, float gain)
	{
		auto i = m_sounds_playing.find(id);
		if (i == m_sounds_playing.end())
			return false;

		PlayingSound *sound = i->second;
		alSourcef(sound->source_id, AL_GAIN, gain);
		return true;
	}

	float getSoundGain(int id)
	{
		auto i = m_sounds_playing.find(id);
		if (i == m_sounds_playing.end())
			return 0;

		PlayingSound *sound = i->second;
		ALfloat gain;
		alGetSourcef(sound->source_id, AL_GAIN, &gain);
		return gain;
	}
};

std::shared_ptr<SoundManagerSingleton> createSoundManagerSingleton()
{
	auto smg = std::make_shared<SoundManagerSingleton>();
	if (!smg->init()) {
		smg.reset();
	}
	return smg;
}

ISoundManager *createOpenALSoundManager(SoundManagerSingleton *smg, OnDemandSoundFetcher *fetcher)
{
	return new OpenALSoundManager(smg, fetcher);
};