2 * OpenAL Direct Context Example
4 * Copyright (c) 2024 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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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 playing a sound buffer with the Direct API
37 #include <string_view>
47 #include "common/alhelpers.h"
49 #include "win_main_utf8.h"
53 /* On Windows when using Creative's router, we need to override the ALC
54 * functions and access the driver functions directly. This isn't needed when
55 * not using the router, or on other OSs.
57 LPALCOPENDEVICE p_alcOpenDevice
{alcOpenDevice
};
58 LPALCCLOSEDEVICE p_alcCloseDevice
{alcCloseDevice
};
59 LPALCISEXTENSIONPRESENT p_alcIsExtensionPresent
{alcIsExtensionPresent
};
60 LPALCCREATECONTEXT p_alcCreateContext
{alcCreateContext
};
61 LPALCDESTROYCONTEXT p_alcDestroyContext
{alcDestroyContext
};
62 LPALCGETPROCADDRESS p_alcGetProcAddress
{alcGetProcAddress
};
65 LPALGETSTRINGDIRECT alGetStringDirect
{};
66 LPALGETERRORDIRECT alGetErrorDirect
{};
67 LPALISEXTENSIONPRESENTDIRECT alIsExtensionPresentDirect
{};
69 LPALGENBUFFERSDIRECT alGenBuffersDirect
{};
70 LPALDELETEBUFFERSDIRECT alDeleteBuffersDirect
{};
71 LPALISBUFFERDIRECT alIsBufferDirect
{};
72 LPALBUFFERIDIRECT alBufferiDirect
{};
73 LPALBUFFERDATADIRECT alBufferDataDirect
{};
75 LPALGENSOURCESDIRECT alGenSourcesDirect
{};
76 LPALDELETESOURCESDIRECT alDeleteSourcesDirect
{};
77 LPALSOURCEIDIRECT alSourceiDirect
{};
78 LPALGETSOURCEIDIRECT alGetSourceiDirect
{};
79 LPALGETSOURCEFDIRECT alGetSourcefDirect
{};
80 LPALSOURCEPLAYDIRECT alSourcePlayDirect
{};
83 struct SndFileDeleter
{
84 void operator()(SNDFILE
*sndfile
) { sf_close(sndfile
); }
86 using SndFilePtr
= std::unique_ptr
<SNDFILE
,SndFileDeleter
>;
88 enum class FormatType
{
95 /* LoadBuffer loads the named audio file into an OpenAL buffer object, and
96 * returns the new buffer ID.
98 ALuint
LoadSound(ALCcontext
*context
, const std::string_view filename
)
100 /* Open the audio file and check that it's usable. */
102 SndFilePtr sndfile
{sf_open(std::string
{filename
}.c_str(), SFM_READ
, &sfinfo
)};
105 std::cerr
<< "Could not open audio in "<<filename
<<": "<<sf_strerror(sndfile
.get())<<"\n";
108 if(sfinfo
.frames
< 1)
110 std::cerr
<< "Bad sample count in "<<filename
<<" ("<<sfinfo
.frames
<<")\n";
114 /* Detect a suitable format to load. Formats like Vorbis and Opus use float
115 * natively, so load as float to avoid clipping when possible. Formats
116 * larger than 16-bit can also use float to preserve a bit more precision.
118 FormatType sample_format
{FormatType::Int16
};
119 switch((sfinfo
.format
&SF_FORMAT_SUBMASK
))
121 case SF_FORMAT_PCM_24
:
122 case SF_FORMAT_PCM_32
:
123 case SF_FORMAT_FLOAT
:
124 case SF_FORMAT_DOUBLE
:
125 case SF_FORMAT_VORBIS
:
127 case SF_FORMAT_ALAC_20
:
128 case SF_FORMAT_ALAC_24
:
129 case SF_FORMAT_ALAC_32
:
130 case 0x0080/*SF_FORMAT_MPEG_LAYER_I*/:
131 case 0x0081/*SF_FORMAT_MPEG_LAYER_II*/:
132 case 0x0082/*SF_FORMAT_MPEG_LAYER_III*/:
133 if(alIsExtensionPresentDirect(context
, "AL_EXT_FLOAT32"))
134 sample_format
= FormatType::Float
;
136 case SF_FORMAT_IMA_ADPCM
:
137 /* ADPCM formats require setting a block alignment as specified in the
138 * file, which needs to be read from the wave 'fmt ' chunk manually
139 * since libsndfile doesn't provide it in a format-agnostic way.
141 if(sfinfo
.channels
<= 2 && (sfinfo
.format
&SF_FORMAT_TYPEMASK
) == SF_FORMAT_WAV
142 && alIsExtensionPresentDirect(context
, "AL_EXT_IMA4")
143 && alIsExtensionPresentDirect(context
, "AL_SOFT_block_alignment"))
144 sample_format
= FormatType::IMA4
;
146 case SF_FORMAT_MS_ADPCM
:
147 if(sfinfo
.channels
<= 2 && (sfinfo
.format
&SF_FORMAT_TYPEMASK
) == SF_FORMAT_WAV
148 && alIsExtensionPresentDirect(context
, "AL_SOFT_MSADPCM")
149 && alIsExtensionPresentDirect(context
, "AL_SOFT_block_alignment"))
150 sample_format
= FormatType::MSADPCM
;
154 ALint byteblockalign
{0}, splblockalign
{0};
155 if(sample_format
== FormatType::IMA4
|| sample_format
== FormatType::MSADPCM
)
157 /* For ADPCM, lookup the wave file's "fmt " chunk, which is a
158 * WAVEFORMATEX-based structure for the audio format.
160 SF_CHUNK_INFO inf
{"fmt ", 4, 0, nullptr};
161 SF_CHUNK_ITERATOR
*iter
{sf_get_chunk_iterator(sndfile
.get(), &inf
)};
163 /* If there's an issue getting the chunk or block alignment, load as
164 * 16-bit and have libsndfile do the conversion.
166 if(!iter
|| sf_get_chunk_size(iter
, &inf
) != SF_ERR_NO_ERROR
|| inf
.datalen
< 14)
167 sample_format
= FormatType::Int16
;
170 auto fmtbuf
= std::vector
<ALubyte
>(inf
.datalen
, ALubyte
{0});
171 inf
.data
= fmtbuf
.data();
172 if(sf_get_chunk_data(iter
, &inf
) != SF_ERR_NO_ERROR
)
173 sample_format
= FormatType::Int16
;
176 /* Read the nBlockAlign field, and convert from bytes- to
177 * samples-per-block (verifying it's valid by converting back
178 * and comparing to the original value).
180 byteblockalign
= fmtbuf
[12] | (fmtbuf
[13]<<8);
181 if(sample_format
== FormatType::IMA4
)
183 splblockalign
= (byteblockalign
/sfinfo
.channels
- 4)/4*8 + 1;
185 || ((splblockalign
-1)/2 + 4)*sfinfo
.channels
!= byteblockalign
)
186 sample_format
= FormatType::Int16
;
188 else if(sample_format
== FormatType::MSADPCM
)
190 splblockalign
= (byteblockalign
/sfinfo
.channels
- 7)*2 + 2;
192 || ((splblockalign
-2)/2 + 7)*sfinfo
.channels
!= byteblockalign
)
193 sample_format
= FormatType::Int16
;
196 sample_format
= FormatType::Int16
;
201 if(sample_format
== FormatType::Int16
)
204 byteblockalign
= sfinfo
.channels
* 2;
206 else if(sample_format
== FormatType::Float
)
209 byteblockalign
= sfinfo
.channels
* 4;
212 /* Figure out the OpenAL format from the file and desired sample type. */
213 ALenum format
{AL_NONE
};
214 if(sfinfo
.channels
== 1)
216 if(sample_format
== FormatType::Int16
)
217 format
= AL_FORMAT_MONO16
;
218 else if(sample_format
== FormatType::Float
)
219 format
= AL_FORMAT_MONO_FLOAT32
;
220 else if(sample_format
== FormatType::IMA4
)
221 format
= AL_FORMAT_MONO_IMA4
;
222 else if(sample_format
== FormatType::MSADPCM
)
223 format
= AL_FORMAT_MONO_MSADPCM_SOFT
;
225 else if(sfinfo
.channels
== 2)
227 if(sample_format
== FormatType::Int16
)
228 format
= AL_FORMAT_STEREO16
;
229 else if(sample_format
== FormatType::Float
)
230 format
= AL_FORMAT_STEREO_FLOAT32
;
231 else if(sample_format
== FormatType::IMA4
)
232 format
= AL_FORMAT_STEREO_IMA4
;
233 else if(sample_format
== FormatType::MSADPCM
)
234 format
= AL_FORMAT_STEREO_MSADPCM_SOFT
;
236 else if(sfinfo
.channels
== 3)
238 if(sf_command(sndfile
.get(), SFC_WAVEX_GET_AMBISONIC
, nullptr, 0) == SF_AMBISONIC_B_FORMAT
)
240 if(sample_format
== FormatType::Int16
)
241 format
= AL_FORMAT_BFORMAT2D_16
;
242 else if(sample_format
== FormatType::Float
)
243 format
= AL_FORMAT_BFORMAT2D_FLOAT32
;
246 else if(sfinfo
.channels
== 4)
248 if(sf_command(sndfile
.get(), SFC_WAVEX_GET_AMBISONIC
, nullptr, 0) == SF_AMBISONIC_B_FORMAT
)
250 if(sample_format
== FormatType::Int16
)
251 format
= AL_FORMAT_BFORMAT3D_16
;
252 else if(sample_format
== FormatType::Float
)
253 format
= AL_FORMAT_BFORMAT3D_FLOAT32
;
258 std::cerr
<< "Unsupported channel count: "<<sfinfo
.channels
<<"\n";
262 if(sfinfo
.frames
/splblockalign
> sf_count_t
{std::numeric_limits
<int>::max()}/byteblockalign
)
264 std::cerr
<< "Too many sample frames in "<<filename
<<" ("<<sfinfo
.frames
<<")\n";
268 /* Decode the whole audio file to a buffer. */
269 auto membuf
= std::vector
<std::byte
>(static_cast<size_t>(sfinfo
.frames
/ splblockalign
272 sf_count_t num_frames
{};
273 if(sample_format
== FormatType::Int16
)
274 num_frames
= sf_readf_short(sndfile
.get(), reinterpret_cast<short*>(membuf
.data()),
276 else if(sample_format
== FormatType::Float
)
277 num_frames
= sf_readf_float(sndfile
.get(), reinterpret_cast<float*>(membuf
.data()),
281 const sf_count_t count
{sfinfo
.frames
/ splblockalign
* byteblockalign
};
282 num_frames
= sf_read_raw(sndfile
.get(), membuf
.data(), count
);
284 num_frames
= num_frames
/ byteblockalign
* splblockalign
;
288 std::cerr
<< "Failed to read samples in "<<filename
<<" ("<<num_frames
<<")\n";
292 const auto num_bytes
= static_cast<ALsizei
>(num_frames
/ splblockalign
* byteblockalign
);
294 std::cout
<< "Loading: "<<filename
<<" ("<<FormatName(format
)<<", "<<sfinfo
.samplerate
<<"hz)\n"
298 alGenBuffersDirect(context
, 1, &buffer
);
299 if(splblockalign
> 1)
300 alBufferiDirect(context
, buffer
, AL_UNPACK_BLOCK_ALIGNMENT_SOFT
, splblockalign
);
301 alBufferDataDirect(context
, buffer
, format
, membuf
.data(), num_bytes
, sfinfo
.samplerate
);
303 /* Check if an error occurred, and clean up if so. */
304 if(ALenum err
{alGetErrorDirect(context
)}; err
!= AL_NO_ERROR
)
306 std::cerr
<< "OpenAL Error: "<<alGetStringDirect(context
, err
)<<"\n";
307 if(buffer
&& alIsBufferDirect(context
, buffer
))
308 alDeleteBuffersDirect(context
, 1, &buffer
);
316 int main(al::span
<std::string_view
> args
)
318 /* Print out usage if no arguments were specified */
321 std::cerr
<< "Usage: "<<args
[0]<<" [-device <name>] <filename>\n";
325 /* Initialize OpenAL. */
326 args
= args
.subspan(1);
329 if(args
.size() > 1 && args
[0] == "-device")
331 device
= p_alcOpenDevice(std::string
{args
[1]}.c_str());
333 std::cerr
<< "Failed to open \""<<args
[1]<<"\", trying default\n";
334 args
= args
.subspan(2);
337 device
= p_alcOpenDevice(nullptr);
340 std::cerr
<< "Could not open a device!\n";
344 if(!p_alcIsExtensionPresent(device
, "ALC_EXT_direct_context"))
346 std::cerr
<< "ALC_EXT_direct_context not supported on device\n";
347 p_alcCloseDevice(device
);
351 /* On Windows with Creative's router, the device needs to be bootstrapped
352 * to use it through the driver directly. Otherwise the Direct functions
353 * aren't able to recognize the router's ALCcontexts. To handle this, we
354 * use the router's alcOpenDevice, alcGetProcAddress, and alcCloseDevice
355 * functions to open the device with the router, get the device driver's
356 * alcGetProcAddress2 function, and close the device with the router. Then
357 * call alcGetProcAddress2 with the null device handle to get the driver's
358 * functions. Afterward, we can open the device back up using the driver
359 * functions directly and continue on.
361 * Note that this will allow using other devices from the same driver just
362 * fine, but switching to a device on another driver will require using the
363 * original functions from the router (and require re-bootstrapping to use
364 * that driver's functions, if applicable). If controlling multiple devices
365 * with Direct functions from separate drivers simultaneously is desired, a
366 * good strategy may be to associate the driver's ALC and Direct functions
367 * with the ALCdevice and ALCcontext handles created from them.
369 * This is all unnecessary when not using Creative's router, including on
370 * non-Windows OSs or when using OpenAL Soft's router, where the original
371 * ALC functions can be used as normal.
374 const std::string devname
{alcGetString(device
, ALC_ALL_DEVICES_SPECIFIER
)};
375 auto p_alcGetProcAddress2
= reinterpret_cast<LPALCGETPROCADDRESS2
>(
376 p_alcGetProcAddress(device
, "alcGetProcAddress2"));
377 p_alcCloseDevice(device
);
379 /* Load the driver-specific ALC functions we'll be using. */
380 #define LOAD_PROC(N) p_##N = reinterpret_cast<decltype(p_##N)>(p_alcGetProcAddress2(nullptr, #N))
381 LOAD_PROC(alcOpenDevice
);
382 LOAD_PROC(alcCloseDevice
);
383 LOAD_PROC(alcIsExtensionPresent
);
384 LOAD_PROC(alcGetProcAddress
);
385 LOAD_PROC(alcCreateContext
);
386 LOAD_PROC(alcDestroyContext
);
387 LOAD_PROC(alcGetProcAddress
);
389 device
= p_alcOpenDevice(devname
.c_str());
390 assert(device
!= nullptr);
393 /* Load the Direct API functions we're using. */
394 #define LOAD_PROC(N) N = reinterpret_cast<decltype(N)>(p_alcGetProcAddress(device, #N))
395 LOAD_PROC(alGetStringDirect
);
396 LOAD_PROC(alGetErrorDirect
);
397 LOAD_PROC(alIsExtensionPresentDirect
);
399 LOAD_PROC(alGenBuffersDirect
);
400 LOAD_PROC(alDeleteBuffersDirect
);
401 LOAD_PROC(alIsBufferDirect
);
402 LOAD_PROC(alBufferiDirect
);
403 LOAD_PROC(alBufferDataDirect
);
405 LOAD_PROC(alGenSourcesDirect
);
406 LOAD_PROC(alDeleteSourcesDirect
);
407 LOAD_PROC(alSourceiDirect
);
408 LOAD_PROC(alGetSourceiDirect
);
409 LOAD_PROC(alGetSourcefDirect
);
410 LOAD_PROC(alSourcePlayDirect
);
413 /* Create the context. It doesn't need to be set as current to use with the
414 * Direct API functions.
416 ALCcontext
*context
{p_alcCreateContext(device
, nullptr)};
419 p_alcCloseDevice(device
);
420 std::cerr
<< "Could not create a context!\n";
424 /* Load the sound into a buffer. */
425 const ALuint buffer
{LoadSound(context
, args
[0])};
428 p_alcDestroyContext(context
);
429 p_alcCloseDevice(device
);
433 /* Create the source to play the sound with. */
435 alGenSourcesDirect(context
, 1, &source
);
436 alSourceiDirect(context
, source
, AL_BUFFER
, static_cast<ALint
>(buffer
));
437 assert(alGetErrorDirect(context
)==AL_NO_ERROR
&& "Failed to setup sound source");
439 /* Play the sound until it finishes. */
440 alSourcePlayDirect(context
, source
);
443 al_nssleep(10000000);
444 alGetSourceiDirect(context
, source
, AL_SOURCE_STATE
, &state
);
446 /* Get the source offset. */
448 alGetSourcefDirect(context
, source
, AL_SEC_OFFSET
, &offset
);
449 printf("\rOffset: %f ", offset
);
451 } while(alGetErrorDirect(context
) == AL_NO_ERROR
&& state
== AL_PLAYING
);
454 /* All done. Delete resources, and close down OpenAL. */
455 alDeleteSourcesDirect(context
, 1, &source
);
456 alDeleteBuffersDirect(context
, 1, &buffer
);
458 p_alcDestroyContext(context
);
459 p_alcCloseDevice(device
);
466 int main(int argc
, char **argv
)
469 auto args
= std::vector
<std::string_view
>(static_cast<unsigned int>(argc
));
470 std::copy_n(argv
, args
.size(), args
.begin());
471 return main(al::span
{args
});