Mercurial > sdl-ios-xcode
annotate src/audio/dsp/SDL_dspaudio.c @ 1:cf2af46e9e2a
Changes since SDL 1.2.0 release
| author | Sam Lantinga <slouken@lokigames.com> |
|---|---|
| date | Thu, 26 Apr 2001 16:50:19 +0000 |
| parents | 74212992fb08 |
| children | d3bc792e136d |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
| 3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga | |
| 4 | |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
| 20 slouken@devolution.com | |
| 21 */ | |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* Allow access to a raw mixing buffer */ | |
| 29 | |
| 30 #include <stdlib.h> | |
| 31 #include <stdio.h> | |
| 32 #include <string.h> | |
| 33 #include <errno.h> | |
| 34 #include <unistd.h> | |
| 35 #include <fcntl.h> | |
| 36 #include <signal.h> | |
| 37 #include <sys/time.h> | |
| 38 #include <sys/ioctl.h> | |
| 39 #include <sys/stat.h> | |
| 40 #ifdef linux | |
| 41 #include <linux/soundcard.h> | |
| 42 #endif | |
| 43 #ifdef __bsdi__ | |
| 44 #include <sys/soundcard.h> | |
| 45 #endif | |
| 46 #ifdef __FreeBSD__ | |
| 47 #include <machine/soundcard.h> | |
| 48 #endif | |
|
1
cf2af46e9e2a
Changes since SDL 1.2.0 release
Sam Lantinga <slouken@lokigames.com>
parents:
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changeset
|
49 #ifdef __OpenBSD__ |
|
cf2af46e9e2a
Changes since SDL 1.2.0 release
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
50 #include <soundcard.h> |
|
cf2af46e9e2a
Changes since SDL 1.2.0 release
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
51 #endif |
| 0 | 52 #ifdef __USLC__ |
| 53 #include <sys/soundcard.h> | |
| 54 #endif | |
| 55 | |
| 56 #include "SDL_audio.h" | |
| 57 #include "SDL_error.h" | |
| 58 #include "SDL_audiomem.h" | |
| 59 #include "SDL_audio_c.h" | |
| 60 #include "SDL_timer.h" | |
| 61 #include "SDL_audiodev_c.h" | |
| 62 #include "SDL_dspaudio.h" | |
| 63 | |
| 64 /* The tag name used by DSP audio */ | |
| 65 #define DSP_DRIVER_NAME "dsp" | |
| 66 | |
| 67 /* Open the audio device for playback, and don't block if busy */ | |
| 68 /*#define USE_BLOCKING_WRITES*/ | |
| 69 #ifdef USE_BLOCKING_WRITES | |
| 70 #define OPEN_FLAGS O_WRONLY | |
| 71 #else | |
| 72 #define OPEN_FLAGS (O_WRONLY|O_NONBLOCK) | |
| 73 #endif | |
| 74 | |
| 75 /* Audio driver functions */ | |
| 76 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec); | |
| 77 static void DSP_WaitAudio(_THIS); | |
| 78 static void DSP_PlayAudio(_THIS); | |
| 79 static Uint8 *DSP_GetAudioBuf(_THIS); | |
| 80 static void DSP_CloseAudio(_THIS); | |
| 81 | |
| 82 /* Audio driver bootstrap functions */ | |
| 83 | |
| 84 static int Audio_Available(void) | |
| 85 { | |
| 86 int fd; | |
| 87 int available; | |
| 88 | |
| 89 available = 0; | |
| 90 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0); | |
| 91 if ( fd >= 0 ) { | |
| 92 available = 1; | |
| 93 close(fd); | |
| 94 } | |
| 95 return(available); | |
| 96 } | |
| 97 | |
| 98 static void Audio_DeleteDevice(SDL_AudioDevice *device) | |
| 99 { | |
| 100 free(device->hidden); | |
| 101 free(device); | |
| 102 } | |
| 103 | |
| 104 static SDL_AudioDevice *Audio_CreateDevice(int devindex) | |
| 105 { | |
| 106 SDL_AudioDevice *this; | |
| 107 | |
| 108 /* Initialize all variables that we clean on shutdown */ | |
| 109 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice)); | |
| 110 if ( this ) { | |
| 111 memset(this, 0, (sizeof *this)); | |
| 112 this->hidden = (struct SDL_PrivateAudioData *) | |
| 113 malloc((sizeof *this->hidden)); | |
| 114 } | |
| 115 if ( (this == NULL) || (this->hidden == NULL) ) { | |
| 116 SDL_OutOfMemory(); | |
| 117 if ( this ) { | |
| 118 free(this); | |
| 119 } | |
| 120 return(0); | |
| 121 } | |
| 122 memset(this->hidden, 0, (sizeof *this->hidden)); | |
| 123 audio_fd = -1; | |
| 124 | |
| 125 /* Set the function pointers */ | |
| 126 this->OpenAudio = DSP_OpenAudio; | |
| 127 this->WaitAudio = DSP_WaitAudio; | |
| 128 this->PlayAudio = DSP_PlayAudio; | |
| 129 this->GetAudioBuf = DSP_GetAudioBuf; | |
| 130 this->CloseAudio = DSP_CloseAudio; | |
| 131 | |
| 132 this->free = Audio_DeleteDevice; | |
| 133 | |
| 134 return this; | |
| 135 } | |
| 136 | |
| 137 AudioBootStrap DSP_bootstrap = { | |
| 138 DSP_DRIVER_NAME, "OSS /dev/dsp standard audio", | |
| 139 Audio_Available, Audio_CreateDevice | |
| 140 }; | |
| 141 | |
| 142 /* This function waits until it is possible to write a full sound buffer */ | |
| 143 static void DSP_WaitAudio(_THIS) | |
| 144 { | |
| 145 #ifndef USE_BLOCKING_WRITES /* Not necessary because of blocking writes */ | |
| 146 fd_set fdset; | |
| 147 | |
| 148 /* Check to see if the thread-parent process is still alive */ | |
| 149 { static int cnt = 0; | |
| 150 /* Note that this only works with thread implementations | |
| 151 that use a different process id for each thread. | |
| 152 */ | |
| 153 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */ | |
| 154 if ( kill(parent, 0) < 0 ) { | |
| 155 this->enabled = 0; | |
| 156 } | |
| 157 } | |
| 158 } | |
| 159 | |
| 160 /* See if we need to use timed audio synchronization */ | |
| 161 if ( frame_ticks ) { | |
| 162 /* Use timer for general audio synchronization */ | |
| 163 Sint32 ticks; | |
| 164 | |
| 165 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS; | |
| 166 if ( ticks > 0 ) { | |
| 167 SDL_Delay(ticks); | |
| 168 } | |
| 169 } else { | |
| 170 /* Use select() for audio synchronization */ | |
| 171 struct timeval timeout; | |
| 172 FD_ZERO(&fdset); | |
| 173 FD_SET(audio_fd, &fdset); | |
| 174 timeout.tv_sec = 10; | |
| 175 timeout.tv_usec = 0; | |
| 176 #ifdef DEBUG_AUDIO | |
| 177 fprintf(stderr, "Waiting for audio to get ready\n"); | |
| 178 #endif | |
| 179 if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) { | |
| 180 const char *message = | |
| 181 "Audio timeout - buggy audio driver? (disabled)"; | |
| 182 /* In general we should never print to the screen, | |
| 183 but in this case we have no other way of letting | |
| 184 the user know what happened. | |
| 185 */ | |
| 186 fprintf(stderr, "SDL: %s\n", message); | |
| 187 this->enabled = 0; | |
| 188 /* Don't try to close - may hang */ | |
| 189 audio_fd = -1; | |
| 190 #ifdef DEBUG_AUDIO | |
| 191 fprintf(stderr, "Done disabling audio\n"); | |
| 192 #endif | |
| 193 } | |
| 194 #ifdef DEBUG_AUDIO | |
| 195 fprintf(stderr, "Ready!\n"); | |
| 196 #endif | |
| 197 } | |
| 198 #endif /* !USE_BLOCKING_WRITES */ | |
| 199 } | |
| 200 | |
| 201 static void DSP_PlayAudio(_THIS) | |
| 202 { | |
| 203 int written; | |
| 204 | |
| 205 /* Write the audio data, checking for EAGAIN on broken audio drivers */ | |
| 206 do { | |
| 207 written = write(audio_fd, mixbuf, mixlen); | |
| 208 if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) { | |
| 209 SDL_Delay(1); /* Let a little CPU time go by */ | |
| 210 } | |
| 211 } while ( (written < 0) && | |
| 212 ((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) ); | |
| 213 | |
| 214 /* If timer synchronization is enabled, set the next write frame */ | |
| 215 if ( frame_ticks ) { | |
| 216 next_frame += frame_ticks; | |
| 217 } | |
| 218 | |
| 219 /* If we couldn't write, assume fatal error for now */ | |
| 220 if ( written < 0 ) { | |
| 221 this->enabled = 0; | |
| 222 } | |
| 223 #ifdef DEBUG_AUDIO | |
| 224 fprintf(stderr, "Wrote %d bytes of audio data\n", written); | |
| 225 #endif | |
| 226 } | |
| 227 | |
| 228 static Uint8 *DSP_GetAudioBuf(_THIS) | |
| 229 { | |
| 230 return(mixbuf); | |
| 231 } | |
| 232 | |
| 233 static void DSP_CloseAudio(_THIS) | |
| 234 { | |
| 235 if ( mixbuf != NULL ) { | |
| 236 SDL_FreeAudioMem(mixbuf); | |
| 237 mixbuf = NULL; | |
| 238 } | |
| 239 if ( audio_fd >= 0 ) { | |
| 240 close(audio_fd); | |
| 241 audio_fd = -1; | |
| 242 } | |
| 243 } | |
| 244 | |
| 245 static int DSP_ReopenAudio(_THIS, const char *audiodev, int format, | |
| 246 SDL_AudioSpec *spec) | |
| 247 { | |
| 248 int frag_spec; | |
| 249 int value; | |
| 250 | |
| 251 /* Close and then reopen the audio device */ | |
| 252 close(audio_fd); | |
| 253 audio_fd = open(audiodev, O_WRONLY, 0); | |
| 254 if ( audio_fd < 0 ) { | |
| 255 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); | |
| 256 return(-1); | |
| 257 } | |
| 258 | |
| 259 /* Calculate the final parameters for this audio specification */ | |
| 260 SDL_CalculateAudioSpec(spec); | |
| 261 | |
| 262 /* Determine the power of two of the fragment size */ | |
| 263 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec ); | |
| 264 if ( (0x01<<frag_spec) != spec->size ) { | |
| 265 SDL_SetError("Fragment size must be a power of two"); | |
| 266 return(-1); | |
| 267 } | |
| 268 frag_spec |= 0x00020000; /* two fragments, for low latency */ | |
| 269 | |
| 270 /* Set the audio buffering parameters */ | |
| 271 #ifdef DEBUG_AUDIO | |
| 272 fprintf(stderr, "Requesting %d fragments of size %d\n", | |
| 273 (frag_spec >> 16), 1<<(frag_spec&0xFFFF)); | |
| 274 #endif | |
| 275 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) { | |
| 276 fprintf(stderr, "Warning: Couldn't set audio fragment size\n"); | |
| 277 } | |
| 278 #ifdef DEBUG_AUDIO | |
| 279 { audio_buf_info info; | |
| 280 ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info); | |
| 281 fprintf(stderr, "fragments = %d\n", info.fragments); | |
| 282 fprintf(stderr, "fragstotal = %d\n", info.fragstotal); | |
| 283 fprintf(stderr, "fragsize = %d\n", info.fragsize); | |
| 284 fprintf(stderr, "bytes = %d\n", info.bytes); | |
| 285 } | |
| 286 #endif | |
| 287 | |
| 288 /* Set the audio format */ | |
| 289 value = format; | |
| 290 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || | |
| 291 (value != format) ) { | |
| 292 SDL_SetError("Couldn't set audio format"); | |
| 293 return(-1); | |
| 294 } | |
| 295 | |
| 296 /* Set the number of channels of output */ | |
| 297 value = spec->channels; | |
| 298 #ifdef SNDCTL_DSP_CHANNELS | |
| 299 if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) { | |
| 300 #endif | |
| 301 value = (spec->channels > 1); | |
| 302 ioctl(audio_fd, SNDCTL_DSP_STEREO, &value); | |
| 303 value = (value ? 2 : 1); | |
| 304 #ifdef SNDCTL_DSP_CHANNELS | |
| 305 } | |
| 306 #endif | |
| 307 if ( value != spec->channels ) { | |
| 308 SDL_SetError("Couldn't set audio channels"); | |
| 309 return(-1); | |
| 310 } | |
| 311 | |
| 312 /* Set the DSP frequency */ | |
| 313 value = spec->freq; | |
| 314 if ( ioctl(audio_fd, SOUND_PCM_WRITE_RATE, &value) < 0 ) { | |
| 315 SDL_SetError("Couldn't set audio frequency"); | |
| 316 return(-1); | |
| 317 } | |
| 318 spec->freq = value; | |
| 319 | |
| 320 /* We successfully re-opened the audio */ | |
| 321 return(0); | |
| 322 } | |
| 323 | |
| 324 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec) | |
| 325 { | |
| 326 char audiodev[1024]; | |
| 327 int format; | |
| 328 int value; | |
| 329 Uint16 test_format; | |
| 330 | |
| 331 /* Reset the timer synchronization flag */ | |
| 332 frame_ticks = 0.0; | |
| 333 | |
| 334 /* Open the audio device */ | |
| 335 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0); | |
| 336 if ( audio_fd < 0 ) { | |
| 337 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); | |
| 338 return(-1); | |
| 339 } | |
| 340 mixbuf = NULL; | |
| 341 | |
| 342 /* Get a list of supported hardware formats */ | |
| 343 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) { | |
| 344 SDL_SetError("Couldn't get audio format list"); | |
| 345 return(-1); | |
| 346 } | |
| 347 | |
| 348 /* Try for a closest match on audio format */ | |
| 349 format = 0; | |
| 350 for ( test_format = SDL_FirstAudioFormat(spec->format); | |
| 351 ! format && test_format; ) { | |
| 352 #ifdef DEBUG_AUDIO | |
| 353 fprintf(stderr, "Trying format 0x%4.4x\n", test_format); | |
| 354 #endif | |
| 355 switch ( test_format ) { | |
| 356 case AUDIO_U8: | |
| 357 if ( value & AFMT_U8 ) { | |
| 358 format = AFMT_U8; | |
| 359 } | |
| 360 break; | |
| 361 case AUDIO_S8: | |
| 362 if ( value & AFMT_S8 ) { | |
| 363 format = AFMT_S8; | |
| 364 } | |
| 365 break; | |
| 366 case AUDIO_S16LSB: | |
| 367 if ( value & AFMT_S16_LE ) { | |
| 368 format = AFMT_S16_LE; | |
| 369 } | |
| 370 break; | |
| 371 case AUDIO_S16MSB: | |
| 372 if ( value & AFMT_S16_BE ) { | |
| 373 format = AFMT_S16_BE; | |
| 374 } | |
| 375 break; | |
| 376 case AUDIO_U16LSB: | |
| 377 if ( value & AFMT_U16_LE ) { | |
| 378 format = AFMT_U16_LE; | |
| 379 } | |
| 380 break; | |
| 381 case AUDIO_U16MSB: | |
| 382 if ( value & AFMT_U16_BE ) { | |
| 383 format = AFMT_U16_BE; | |
| 384 } | |
| 385 break; | |
| 386 default: | |
| 387 break; | |
| 388 } | |
| 389 if ( ! format ) { | |
| 390 test_format = SDL_NextAudioFormat(); | |
| 391 } | |
| 392 } | |
| 393 if ( format == 0 ) { | |
| 394 SDL_SetError("Couldn't find any hardware audio formats"); | |
| 395 return(-1); | |
| 396 } | |
| 397 spec->format = test_format; | |
| 398 | |
| 399 /* Set the audio format */ | |
| 400 value = format; | |
| 401 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || | |
| 402 (value != format) ) { | |
| 403 SDL_SetError("Couldn't set audio format"); | |
| 404 return(-1); | |
| 405 } | |
| 406 | |
| 407 /* Set the number of channels of output */ | |
| 408 value = spec->channels; | |
| 409 #ifdef SNDCTL_DSP_CHANNELS | |
| 410 if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) { | |
| 411 #endif | |
| 412 value = (spec->channels > 1); | |
| 413 ioctl(audio_fd, SNDCTL_DSP_STEREO, &value); | |
| 414 value = (value ? 2 : 1); | |
| 415 #ifdef SNDCTL_DSP_CHANNELS | |
| 416 } | |
| 417 #endif | |
| 418 spec->channels = value; | |
| 419 | |
| 420 /* Because some drivers don't allow setting the buffer size | |
| 421 after setting the format, we must re-open the audio device | |
| 422 once we know what format and channels are supported | |
| 423 */ | |
| 424 if ( DSP_ReopenAudio(this, audiodev, format, spec) < 0 ) { | |
| 425 /* Error is set by DSP_ReopenAudio() */ | |
| 426 return(-1); | |
| 427 } | |
| 428 | |
| 429 /* Allocate mixing buffer */ | |
| 430 mixlen = spec->size; | |
| 431 mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen); | |
| 432 if ( mixbuf == NULL ) { | |
| 433 return(-1); | |
| 434 } | |
| 435 memset(mixbuf, spec->silence, spec->size); | |
| 436 | |
| 437 #ifndef USE_BLOCKING_WRITES | |
| 438 /* Check to see if we need to use select() workaround */ | |
| 439 { char *workaround; | |
| 440 workaround = getenv("SDL_DSP_NOSELECT"); | |
| 441 if ( workaround ) { | |
| 442 frame_ticks = (float)(spec->samples*1000)/spec->freq; | |
| 443 next_frame = SDL_GetTicks()+frame_ticks; | |
| 444 } | |
| 445 } | |
| 446 #endif /* !USE_BLOCKING_WRITES */ | |
| 447 | |
| 448 /* Get the parent process id (we're the parent of the audio thread) */ | |
| 449 parent = getpid(); | |
| 450 | |
| 451 /* We're ready to rock and roll. :-) */ | |
| 452 return(0); | |
| 453 } |