2 * OpenAL Convolution Reverb Example
4 * Copyright (c) 2020 by Chris Robinson <chris.kcat@gmail.com>
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
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10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 /* This file contains an example for applying convolution reverb to a source. */
39 #include "common/alhelpers.h"
42 #ifndef AL_SOFT_convolution_reverb
43 #define AL_SOFT_convolution_reverb
44 #define AL_EFFECT_CONVOLUTION_REVERB_SOFT 0xA000
48 /* Filter object functions */
49 static LPALGENFILTERS alGenFilters
;
50 static LPALDELETEFILTERS alDeleteFilters
;
51 static LPALISFILTER alIsFilter
;
52 static LPALFILTERI alFilteri
;
53 static LPALFILTERIV alFilteriv
;
54 static LPALFILTERF alFilterf
;
55 static LPALFILTERFV alFilterfv
;
56 static LPALGETFILTERI alGetFilteri
;
57 static LPALGETFILTERIV alGetFilteriv
;
58 static LPALGETFILTERF alGetFilterf
;
59 static LPALGETFILTERFV alGetFilterfv
;
61 /* Effect object functions */
62 static LPALGENEFFECTS alGenEffects
;
63 static LPALDELETEEFFECTS alDeleteEffects
;
64 static LPALISEFFECT alIsEffect
;
65 static LPALEFFECTI alEffecti
;
66 static LPALEFFECTIV alEffectiv
;
67 static LPALEFFECTF alEffectf
;
68 static LPALEFFECTFV alEffectfv
;
69 static LPALGETEFFECTI alGetEffecti
;
70 static LPALGETEFFECTIV alGetEffectiv
;
71 static LPALGETEFFECTF alGetEffectf
;
72 static LPALGETEFFECTFV alGetEffectfv
;
74 /* Auxiliary Effect Slot object functions */
75 static LPALGENAUXILIARYEFFECTSLOTS alGenAuxiliaryEffectSlots
;
76 static LPALDELETEAUXILIARYEFFECTSLOTS alDeleteAuxiliaryEffectSlots
;
77 static LPALISAUXILIARYEFFECTSLOT alIsAuxiliaryEffectSlot
;
78 static LPALAUXILIARYEFFECTSLOTI alAuxiliaryEffectSloti
;
79 static LPALAUXILIARYEFFECTSLOTIV alAuxiliaryEffectSlotiv
;
80 static LPALAUXILIARYEFFECTSLOTF alAuxiliaryEffectSlotf
;
81 static LPALAUXILIARYEFFECTSLOTFV alAuxiliaryEffectSlotfv
;
82 static LPALGETAUXILIARYEFFECTSLOTI alGetAuxiliaryEffectSloti
;
83 static LPALGETAUXILIARYEFFECTSLOTIV alGetAuxiliaryEffectSlotiv
;
84 static LPALGETAUXILIARYEFFECTSLOTF alGetAuxiliaryEffectSlotf
;
85 static LPALGETAUXILIARYEFFECTSLOTFV alGetAuxiliaryEffectSlotfv
;
87 /* C doesn't allow casting between function and non-function pointer types, so
88 * with C99 we need to use a union to reinterpret the pointer type. Pre-C99
89 * still needs to use a normal cast and live with the warning (C++ is fine with
90 * a regular reinterpret_cast).
92 #if __STDC_VERSION__ >= 199901L
93 #define FUNCTION_CAST(T, ptr) (union{void *p; T f;}){ptr}.f
95 #define FUNCTION_CAST(T, ptr) (T)(ptr)
99 /* This stuff defines a simple streaming player object, the same as alstream.c.
100 * Comments are removed for brevity, see alstream.c for more details.
102 #define NUM_BUFFERS 4
103 #define BUFFER_SAMPLES 8192
105 typedef struct StreamPlayer
{
106 ALuint buffers
[NUM_BUFFERS
];
116 static StreamPlayer
*NewPlayer(void)
118 StreamPlayer
*player
;
120 player
= calloc(1, sizeof(*player
));
121 assert(player
!= NULL
);
123 alGenBuffers(NUM_BUFFERS
, player
->buffers
);
124 assert(alGetError() == AL_NO_ERROR
&& "Could not create buffers");
126 alGenSources(1, &player
->source
);
127 assert(alGetError() == AL_NO_ERROR
&& "Could not create source");
129 alSource3i(player
->source
, AL_POSITION
, 0, 0, -1);
130 alSourcei(player
->source
, AL_SOURCE_RELATIVE
, AL_TRUE
);
131 alSourcei(player
->source
, AL_ROLLOFF_FACTOR
, 0);
132 assert(alGetError() == AL_NO_ERROR
&& "Could not set source parameters");
137 static void ClosePlayerFile(StreamPlayer
*player
)
140 sf_close(player
->sndfile
);
141 player
->sndfile
= NULL
;
143 free(player
->membuf
);
144 player
->membuf
= NULL
;
147 static void DeletePlayer(StreamPlayer
*player
)
149 ClosePlayerFile(player
);
151 alDeleteSources(1, &player
->source
);
152 alDeleteBuffers(NUM_BUFFERS
, player
->buffers
);
153 if(alGetError() != AL_NO_ERROR
)
154 fprintf(stderr
, "Failed to delete object IDs\n");
156 memset(player
, 0, sizeof(*player
));
160 static int OpenPlayerFile(StreamPlayer
*player
, const char *filename
)
164 ClosePlayerFile(player
);
166 player
->sndfile
= sf_open(filename
, SFM_READ
, &player
->sfinfo
);
169 fprintf(stderr
, "Could not open audio in %s: %s\n", filename
, sf_strerror(NULL
));
173 player
->format
= AL_NONE
;
174 if(player
->sfinfo
.channels
== 1)
175 player
->format
= AL_FORMAT_MONO_FLOAT32
;
176 else if(player
->sfinfo
.channels
== 2)
177 player
->format
= AL_FORMAT_STEREO_FLOAT32
;
178 else if(player
->sfinfo
.channels
== 6)
179 player
->format
= AL_FORMAT_51CHN32
;
180 else if(player
->sfinfo
.channels
== 3)
182 if(sf_command(player
->sndfile
, SFC_WAVEX_GET_AMBISONIC
, NULL
, 0) == SF_AMBISONIC_B_FORMAT
)
183 player
->format
= AL_FORMAT_BFORMAT2D_FLOAT32
;
185 else if(player
->sfinfo
.channels
== 4)
187 if(sf_command(player
->sndfile
, SFC_WAVEX_GET_AMBISONIC
, NULL
, 0) == SF_AMBISONIC_B_FORMAT
)
188 player
->format
= AL_FORMAT_BFORMAT3D_FLOAT32
;
192 fprintf(stderr
, "Unsupported channel count: %d\n", player
->sfinfo
.channels
);
193 sf_close(player
->sndfile
);
194 player
->sndfile
= NULL
;
198 frame_size
= (size_t)(BUFFER_SAMPLES
* player
->sfinfo
.channels
) * sizeof(float);
199 player
->membuf
= malloc(frame_size
);
204 static int StartPlayer(StreamPlayer
*player
)
208 alSourceRewind(player
->source
);
209 alSourcei(player
->source
, AL_BUFFER
, 0);
211 for(i
= 0;i
< NUM_BUFFERS
;i
++)
213 sf_count_t slen
= sf_readf_float(player
->sndfile
, player
->membuf
, BUFFER_SAMPLES
);
216 slen
*= player
->sfinfo
.channels
* (sf_count_t
)sizeof(float);
217 alBufferData(player
->buffers
[i
], player
->format
, player
->membuf
, (ALsizei
)slen
,
218 player
->sfinfo
.samplerate
);
220 if(alGetError() != AL_NO_ERROR
)
222 fprintf(stderr
, "Error buffering for playback\n");
226 alSourceQueueBuffers(player
->source
, i
, player
->buffers
);
227 alSourcePlay(player
->source
);
228 if(alGetError() != AL_NO_ERROR
)
230 fprintf(stderr
, "Error starting playback\n");
237 static int UpdatePlayer(StreamPlayer
*player
)
239 ALint processed
, state
;
241 alGetSourcei(player
->source
, AL_SOURCE_STATE
, &state
);
242 alGetSourcei(player
->source
, AL_BUFFERS_PROCESSED
, &processed
);
243 if(alGetError() != AL_NO_ERROR
)
245 fprintf(stderr
, "Error checking source state\n");
254 alSourceUnqueueBuffers(player
->source
, 1, &bufid
);
257 slen
= sf_readf_float(player
->sndfile
, player
->membuf
, BUFFER_SAMPLES
);
260 slen
*= player
->sfinfo
.channels
* (sf_count_t
)sizeof(float);
261 alBufferData(bufid
, player
->format
, player
->membuf
, (ALsizei
)slen
,
262 player
->sfinfo
.samplerate
);
263 alSourceQueueBuffers(player
->source
, 1, &bufid
);
265 if(alGetError() != AL_NO_ERROR
)
267 fprintf(stderr
, "Error buffering data\n");
272 if(state
!= AL_PLAYING
&& state
!= AL_PAUSED
)
276 alGetSourcei(player
->source
, AL_BUFFERS_QUEUED
, &queued
);
280 alSourcePlay(player
->source
);
281 if(alGetError() != AL_NO_ERROR
)
283 fprintf(stderr
, "Error restarting playback\n");
292 /* CreateEffect creates a new OpenAL effect object with a convolution reverb
293 * type, and returns the new effect ID.
295 static ALuint
CreateEffect(void)
300 printf("Using Convolution Reverb\n");
302 /* Create the effect object and set the convolution reverb effect type. */
303 alGenEffects(1, &effect
);
304 alEffecti(effect
, AL_EFFECT_TYPE
, AL_EFFECT_CONVOLUTION_REVERB_SOFT
);
306 /* Check if an error occured, and clean up if so. */
308 if(err
!= AL_NO_ERROR
)
310 fprintf(stderr
, "OpenAL error: %s\n", alGetString(err
));
311 if(alIsEffect(effect
))
312 alDeleteEffects(1, &effect
);
319 /* LoadBuffer loads the named audio file into an OpenAL buffer object, and
320 * returns the new buffer ID.
322 static ALuint
LoadSound(const char *filename
)
324 const char *namepart
;
330 sf_count_t num_frames
;
333 /* Open the audio file and check that it's usable. */
334 sndfile
= sf_open(filename
, SFM_READ
, &sfinfo
);
337 fprintf(stderr
, "Could not open audio in %s: %s\n", filename
, sf_strerror(sndfile
));
340 if(sfinfo
.frames
< 1 || sfinfo
.frames
> (sf_count_t
)(INT_MAX
/sizeof(float))/sfinfo
.channels
)
342 fprintf(stderr
, "Bad sample count in %s (%" PRId64
")\n", filename
, sfinfo
.frames
);
347 /* Get the sound format, and figure out the OpenAL format. Use floats since
348 * impulse responses will usually have more than 16-bit precision.
351 if(sfinfo
.channels
== 1)
352 format
= AL_FORMAT_MONO_FLOAT32
;
353 else if(sfinfo
.channels
== 2)
354 format
= AL_FORMAT_STEREO_FLOAT32
;
355 else if(sfinfo
.channels
== 3)
357 if(sf_command(sndfile
, SFC_WAVEX_GET_AMBISONIC
, NULL
, 0) == SF_AMBISONIC_B_FORMAT
)
358 format
= AL_FORMAT_BFORMAT2D_FLOAT32
;
360 else if(sfinfo
.channels
== 4)
362 if(sf_command(sndfile
, SFC_WAVEX_GET_AMBISONIC
, NULL
, 0) == SF_AMBISONIC_B_FORMAT
)
363 format
= AL_FORMAT_BFORMAT3D_FLOAT32
;
367 fprintf(stderr
, "Unsupported channel count: %d\n", sfinfo
.channels
);
372 namepart
= strrchr(filename
, '/');
373 if(namepart
|| (namepart
=strrchr(filename
, '\\')))
377 printf("Loading: %s (%s, %dhz, %" PRId64
" samples / %.2f seconds)\n", namepart
,
378 FormatName(format
), sfinfo
.samplerate
, sfinfo
.frames
,
379 (double)sfinfo
.frames
/ sfinfo
.samplerate
);
382 /* Decode the whole audio file to a buffer. */
383 membuf
= malloc((size_t)(sfinfo
.frames
* sfinfo
.channels
) * sizeof(float));
385 num_frames
= sf_readf_float(sndfile
, membuf
, sfinfo
.frames
);
390 fprintf(stderr
, "Failed to read samples in %s (%" PRId64
")\n", filename
, num_frames
);
393 num_bytes
= (ALsizei
)(num_frames
* sfinfo
.channels
) * (ALsizei
)sizeof(float);
395 /* Buffer the audio data into a new buffer object, then free the data and
399 alGenBuffers(1, &buffer
);
400 alBufferData(buffer
, format
, membuf
, num_bytes
, sfinfo
.samplerate
);
405 /* Check if an error occured, and clean up if so. */
407 if(err
!= AL_NO_ERROR
)
409 fprintf(stderr
, "OpenAL Error: %s\n", alGetString(err
));
410 if(buffer
&& alIsBuffer(buffer
))
411 alDeleteBuffers(1, &buffer
);
419 int main(int argc
, char **argv
)
421 ALuint ir_buffer
, filter
, effect
, slot
;
422 StreamPlayer
*player
;
425 /* Print out usage if no arguments were specified */
428 fprintf(stderr
, "Usage: %s [-device <name>] <impulse response file> "
429 "<[-dry | -nodry] filename>...\n", argv
[0]);
434 if(InitAL(&argv
, &argc
) != 0)
437 if(!alIsExtensionPresent("AL_SOFTX_convolution_reverb"))
440 fprintf(stderr
, "Error: Convolution revern not supported\n");
447 fprintf(stderr
, "Error: Missing impulse response or sound files\n");
451 /* Define a macro to help load the function pointers. */
452 #define LOAD_PROC(T, x) ((x) = FUNCTION_CAST(T, alGetProcAddress(#x)))
453 LOAD_PROC(LPALGENFILTERS
, alGenFilters
);
454 LOAD_PROC(LPALDELETEFILTERS
, alDeleteFilters
);
455 LOAD_PROC(LPALISFILTER
, alIsFilter
);
456 LOAD_PROC(LPALFILTERI
, alFilteri
);
457 LOAD_PROC(LPALFILTERIV
, alFilteriv
);
458 LOAD_PROC(LPALFILTERF
, alFilterf
);
459 LOAD_PROC(LPALFILTERFV
, alFilterfv
);
460 LOAD_PROC(LPALGETFILTERI
, alGetFilteri
);
461 LOAD_PROC(LPALGETFILTERIV
, alGetFilteriv
);
462 LOAD_PROC(LPALGETFILTERF
, alGetFilterf
);
463 LOAD_PROC(LPALGETFILTERFV
, alGetFilterfv
);
465 LOAD_PROC(LPALGENEFFECTS
, alGenEffects
);
466 LOAD_PROC(LPALDELETEEFFECTS
, alDeleteEffects
);
467 LOAD_PROC(LPALISEFFECT
, alIsEffect
);
468 LOAD_PROC(LPALEFFECTI
, alEffecti
);
469 LOAD_PROC(LPALEFFECTIV
, alEffectiv
);
470 LOAD_PROC(LPALEFFECTF
, alEffectf
);
471 LOAD_PROC(LPALEFFECTFV
, alEffectfv
);
472 LOAD_PROC(LPALGETEFFECTI
, alGetEffecti
);
473 LOAD_PROC(LPALGETEFFECTIV
, alGetEffectiv
);
474 LOAD_PROC(LPALGETEFFECTF
, alGetEffectf
);
475 LOAD_PROC(LPALGETEFFECTFV
, alGetEffectfv
);
477 LOAD_PROC(LPALGENAUXILIARYEFFECTSLOTS
, alGenAuxiliaryEffectSlots
);
478 LOAD_PROC(LPALDELETEAUXILIARYEFFECTSLOTS
, alDeleteAuxiliaryEffectSlots
);
479 LOAD_PROC(LPALISAUXILIARYEFFECTSLOT
, alIsAuxiliaryEffectSlot
);
480 LOAD_PROC(LPALAUXILIARYEFFECTSLOTI
, alAuxiliaryEffectSloti
);
481 LOAD_PROC(LPALAUXILIARYEFFECTSLOTIV
, alAuxiliaryEffectSlotiv
);
482 LOAD_PROC(LPALAUXILIARYEFFECTSLOTF
, alAuxiliaryEffectSlotf
);
483 LOAD_PROC(LPALAUXILIARYEFFECTSLOTFV
, alAuxiliaryEffectSlotfv
);
484 LOAD_PROC(LPALGETAUXILIARYEFFECTSLOTI
, alGetAuxiliaryEffectSloti
);
485 LOAD_PROC(LPALGETAUXILIARYEFFECTSLOTIV
, alGetAuxiliaryEffectSlotiv
);
486 LOAD_PROC(LPALGETAUXILIARYEFFECTSLOTF
, alGetAuxiliaryEffectSlotf
);
487 LOAD_PROC(LPALGETAUXILIARYEFFECTSLOTFV
, alGetAuxiliaryEffectSlotfv
);
490 /* Load the reverb into an effect. */
491 effect
= CreateEffect();
498 /* Load the impulse response sound into a buffer. */
499 ir_buffer
= LoadSound(argv
[0]);
502 alDeleteEffects(1, &effect
);
507 /* Create the effect slot object. This is what "plays" an effect on sources
508 * that connect to it.
511 alGenAuxiliaryEffectSlots(1, &slot
);
513 /* Set the impulse response sound buffer on the effect slot. This allows
514 * effects to access it as needed. In this case, convolution reverb uses it
515 * as the filter source. NOTE: Unlike the effect object, the buffer *is*
516 * kept referenced and may not be changed or deleted as long as it's set,
517 * just like with a source. When another buffer is set, or the effect slot
518 * is deleted, the buffer reference is released.
520 * The effect slot's gain is reduced because the impulse responses I've
521 * tested with result in excessively loud reverb. Is that normal? Even with
522 * this, it seems a bit on the loud side.
524 * Also note: unlike standard or EAX reverb, there is no automatic
525 * attenuation of a source's reverb response with distance, so the reverb
526 * will remain full volume regardless of a given sound's distance from the
527 * listener. You can use a send filter to alter a given source's
528 * contribution to reverb.
530 alAuxiliaryEffectSloti(slot
, AL_BUFFER
, (ALint
)ir_buffer
);
531 alAuxiliaryEffectSlotf(slot
, AL_EFFECTSLOT_GAIN
, 1.0f
/ 16.0f
);
532 alAuxiliaryEffectSloti(slot
, AL_EFFECTSLOT_EFFECT
, (ALint
)effect
);
533 assert(alGetError()==AL_NO_ERROR
&& "Failed to set effect slot");
535 /* Create a filter that can silence the dry path. */
537 alGenFilters(1, &filter
);
538 alFilteri(filter
, AL_FILTER_TYPE
, AL_FILTER_LOWPASS
);
539 alFilterf(filter
, AL_LOWPASS_GAIN
, 0.0f
);
541 player
= NewPlayer();
542 /* Connect the player's source to the effect slot. */
543 alSource3i(player
->source
, AL_AUXILIARY_SEND_FILTER
, (ALint
)slot
, 0, AL_FILTER_NULL
);
544 assert(alGetError()==AL_NO_ERROR
&& "Failed to setup sound source");
546 /* Play each file listed on the command line */
547 for(i
= 1;i
< argc
;i
++)
549 const char *namepart
;
553 if(strcasecmp(argv
[i
], "-nodry") == 0)
555 alSourcei(player
->source
, AL_DIRECT_FILTER
, (ALint
)filter
);
558 else if(strcasecmp(argv
[i
], "-dry") == 0)
560 alSourcei(player
->source
, AL_DIRECT_FILTER
, AL_FILTER_NULL
);
565 if(!OpenPlayerFile(player
, argv
[i
]))
568 namepart
= strrchr(argv
[i
], '/');
569 if(namepart
|| (namepart
=strrchr(argv
[i
], '\\')))
574 printf("Playing: %s (%s, %dhz)\n", namepart
, FormatName(player
->format
),
575 player
->sfinfo
.samplerate
);
578 if(!StartPlayer(player
))
580 ClosePlayerFile(player
);
584 while(UpdatePlayer(player
))
585 al_nssleep(10000000);
587 ClosePlayerFile(player
);
591 /* All files done. Delete the player and effect resources, and close down
594 DeletePlayer(player
);
597 alDeleteAuxiliaryEffectSlots(1, &slot
);
598 alDeleteEffects(1, &effect
);
599 alDeleteFilters(1, &filter
);
600 alDeleteBuffers(1, &ir_buffer
);