Mercurial > sdl-ios-xcode
annotate src/audio/nto/SDL_nto_audio.c @ 277:255c7ee077cb
Added a YUV overlay test program (thanks Jon!)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 14 Feb 2002 00:47:46 +0000 |
| parents | e8157fcb3114 |
| children | 3d8b6b9f1e18 |
| 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 | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
|
20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 | |
| 24 | |
| 25 /* Allow access to a raw mixing buffer */ | |
| 26 | |
| 27 #include <stdlib.h> | |
| 28 #include <stdio.h> | |
| 29 #include <string.h> | |
| 30 #include <errno.h> | |
| 31 #include <unistd.h> | |
| 32 #include <fcntl.h> | |
| 33 #include <signal.h> | |
| 34 #include <sys/types.h> | |
| 35 #include <sys/time.h> | |
| 36 #include <sched.h> | |
| 37 #include <sys/asoundlib.h> | |
| 38 | |
| 39 #include "SDL_audio.h" | |
| 40 #include "SDL_error.h" | |
| 41 #include "SDL_audiomem.h" | |
| 42 #include "SDL_audio_c.h" | |
| 43 #include "SDL_timer.h" | |
| 44 #include "SDL_nto_audio.h" | |
| 45 | |
| 46 /* The tag name used by NTO audio */ | |
| 47 #define DRIVER_NAME "nto" | |
| 48 | |
| 49 /* default card and device numbers as listed in dev/snd */ | |
| 50 static int card_no = 0; | |
| 51 static int device_no = 0; | |
| 52 | |
| 53 /* default channel communication parameters */ | |
| 54 #define DEFAULT_CPARAMS_RATE 22050 | |
| 55 #define DEFAULT_CPARAMS_VOICES 1 | |
| 56 #define DEFAULT_CPARAMS_FRAG_SIZE 4096 //was 512 | |
| 57 #define DEFAULT_CPARAMS_FRAGS_MIN 1 | |
| 58 #define DEFAULT_CPARAMS_FRAGS_MAX -1 | |
| 59 | |
| 60 /* Open the audio device for playback, and don't block if busy */ | |
| 61 #define OPEN_FLAGS SND_PCM_OPEN_PLAYBACK | |
| 62 | |
| 63 /* Audio driver functions */ | |
| 64 static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec); | |
| 65 static void NTO_WaitAudio(_THIS); | |
| 66 static void NTO_PlayAudio(_THIS); | |
| 67 static Uint8 *NTO_GetAudioBuf(_THIS); | |
| 68 static void NTO_CloseAudio(_THIS); | |
| 69 | |
| 70 static snd_pcm_channel_status_t cstatus; | |
| 71 static snd_pcm_channel_params_t cparams; | |
| 72 static snd_pcm_channel_setup_t csetup; | |
| 73 | |
| 74 /* PCM transfer channel parameters initialize function */ | |
| 75 static void init_pcm_cparams(snd_pcm_channel_params_t* cparams) | |
| 76 { | |
| 77 memset(cparams,0,sizeof(snd_pcm_channel_params_t)); | |
| 78 | |
| 79 cparams->channel = SND_PCM_CHANNEL_PLAYBACK; | |
| 80 cparams->mode = SND_PCM_MODE_BLOCK; | |
| 81 cparams->start_mode = SND_PCM_START_DATA; //_FULL | |
| 82 cparams->stop_mode = SND_PCM_STOP_STOP; | |
| 83 cparams->format.format = SND_PCM_SFMT_S16_LE; | |
| 84 cparams->format.interleave = 1; | |
| 85 cparams->format.rate = DEFAULT_CPARAMS_RATE; | |
| 86 cparams->format.voices = DEFAULT_CPARAMS_VOICES; | |
| 87 cparams->buf.block.frag_size = DEFAULT_CPARAMS_FRAG_SIZE; | |
| 88 cparams->buf.block.frags_min = DEFAULT_CPARAMS_FRAGS_MIN; | |
| 89 cparams->buf.block.frags_max = DEFAULT_CPARAMS_FRAGS_MAX; | |
| 90 } | |
| 91 | |
| 92 /* Audio driver bootstrap functions */ | |
| 93 | |
| 94 static int Audio_Available(void) | |
| 95 /* | |
| 96 See if we can open a nonblocking channel. | |
| 97 Return value '1' means we can. | |
| 98 Return value '0' means we cannot. | |
| 99 */ | |
| 100 { | |
| 101 int available; | |
| 102 int rval; | |
| 103 snd_pcm_t *handle; | |
| 104 | |
| 105 available = 0; | |
| 106 handle = NULL; | |
| 107 | |
| 108 //JB modified to take advantage of software mixer | |
| 109 rval = snd_pcm_open_preferred(&handle, &card_no, &device_no, OPEN_FLAGS); | |
| 110 | |
| 111 if (rval >= 0) | |
| 112 { | |
| 113 available = 1; | |
| 114 | |
| 115 if ((rval = snd_pcm_close(handle)) < 0) | |
| 116 { | |
| 117 SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval)); | |
| 118 available = 0; | |
| 119 } | |
| 120 } | |
| 121 else | |
| 122 { | |
| 123 | |
| 124 SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval)); | |
| 125 } | |
| 126 | |
| 127 #ifdef DEBUG_AUDIO | |
| 128 fprintf(stderr,"AudioAvailable rtns %d\n", available); | |
| 129 #endif | |
| 130 return(available); | |
| 131 } | |
| 132 | |
| 133 static void Audio_DeleteDevice(SDL_AudioDevice *device) | |
| 134 { | |
| 135 #ifdef DEBUG_AUDIO | |
| 136 fprintf(stderr,"Audio_DeleteDevice\n"); | |
| 137 #endif | |
| 138 | |
| 139 | |
| 140 free(device->hidden); | |
| 141 free(device); | |
| 142 } | |
| 143 | |
| 144 static SDL_AudioDevice *Audio_CreateDevice(int devindex) | |
| 145 { | |
| 146 SDL_AudioDevice *this; | |
| 147 #ifdef DEBUG_AUDIO | |
| 148 fprintf(stderr,"Audio_CreateDevice\n"); | |
| 149 #endif | |
| 150 /* Initialize all variables that we clean on shutdown */ | |
| 151 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice)); | |
| 152 if ( this ) { | |
| 153 memset(this, 0, (sizeof *this)); | |
| 154 this->hidden = (struct SDL_PrivateAudioData *) | |
| 155 malloc((sizeof *this->hidden)); | |
| 156 } | |
| 157 if ( (this == NULL) || (this->hidden == NULL) ) { | |
| 158 SDL_OutOfMemory(); | |
| 159 if ( this ) { | |
| 160 free(this); | |
| 161 } | |
| 162 return(0); | |
| 163 } | |
| 164 memset(this->hidden, 0, (sizeof *this->hidden)); | |
| 165 audio_handle = NULL; | |
| 166 | |
| 167 /* Set the function pointers */ | |
| 168 this->OpenAudio = NTO_OpenAudio; | |
| 169 this->WaitAudio = NTO_WaitAudio; | |
| 170 this->PlayAudio = NTO_PlayAudio; | |
| 171 this->GetAudioBuf = NTO_GetAudioBuf; | |
| 172 this->CloseAudio = NTO_CloseAudio; | |
| 173 | |
| 174 this->free = Audio_DeleteDevice; | |
| 175 | |
| 176 return this; | |
| 177 } | |
| 178 | |
| 179 /* Don't change the name from "ALSA_bootstrap" - that's how it's called */ | |
| 180 AudioBootStrap ALSA_bootstrap = { | |
| 181 DRIVER_NAME, "Neutrino PCM audio", | |
| 182 Audio_Available, Audio_CreateDevice | |
| 183 }; | |
| 184 | |
| 185 /* This function waits until it is possible to write a full sound buffer */ | |
| 186 static void NTO_WaitAudio(_THIS) | |
| 187 { | |
| 188 int rval; | |
| 189 int totalbytes,roomavail; | |
| 190 /*we consider a full sound buffer to be of size pcm_len bytes */ | |
| 191 | |
| 192 #ifdef DEBUG_AUDIO | |
| 193 fprintf(stderr,"NTO_WaitAudio\n"); | |
| 194 #endif | |
| 195 | |
| 196 while(1) | |
| 197 { | |
| 198 memset(&cstatus, 0, sizeof(cstatus)); | |
| 199 if( (rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0 ) | |
| 200 { | |
| 201 SDL_SetError("snd_pcm_plugin_status failed: %s\n", snd_strerror(rval)); | |
| 202 return; | |
| 203 } | |
| 204 | |
| 205 totalbytes = csetup.buf.block.frag_size *csetup.buf.block.frags; | |
| 206 roomavail = totalbytes - cstatus.count; | |
| 207 | |
| 208 #ifdef DEBUG_AUDIO | |
| 209 fprintf(stderr,"NTO_WaitAudio roomavail %d pcm_len %d\n",roomavail,pcm_len); | |
| 210 #endif | |
| 211 | |
| 212 if ((roomavail >= pcm_len) || (roomavail < 0)) | |
| 213 return; | |
| 214 | |
| 215 SDL_Delay(10); | |
| 216 } | |
| 217 | |
| 218 } | |
| 219 | |
| 220 | |
| 221 | |
| 222 static void NTO_PlayAudio(_THIS) | |
| 223 { | |
| 224 int written, rval; | |
| 225 int towrite; | |
| 226 | |
| 227 #ifdef DEBUG_AUDIO | |
| 228 fprintf(stderr, "NTO_PlayAudio\n"); | |
| 229 #endif | |
| 230 | |
| 231 if( !this->enabled) | |
| 232 return; | |
| 233 | |
| 234 towrite = pcm_len; | |
| 235 | |
| 236 | |
| 237 /* Write the audio data, checking for EAGAIN (buffer full) and underrun */ | |
| 238 do { | |
| 239 written = snd_pcm_plugin_write(audio_handle, pcm_buf, towrite); | |
| 240 #ifdef DEBUG_AUDIO | |
| 241 fprintf(stderr, "NTO_PlayAudio: written = %d towrite = %d\n",written,towrite); | |
| 242 #endif | |
| 243 if (written != towrite) | |
| 244 { | |
| 245 if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) | |
| 246 { | |
| 247 SDL_Delay(1); /* Let a little CPU time go by and try to write again */ | |
| 248 #ifdef DEBUG_AUDIO | |
| 249 fprintf(stderr, "errno == EAGAIN written %d\n", written); | |
| 250 towrite -= written; //we wrote some data | |
| 251 #endif | |
| 252 continue; | |
| 253 } | |
| 254 else if((errno == EINVAL) || (errno == EIO)) | |
| 255 { | |
| 256 #ifdef DEBUG_AUDIO | |
| 257 if(errno == EIO) | |
| 258 fprintf(stderr,"snd_pcm_plugin_write failed EIO: %s\n", snd_strerror(written)); | |
| 259 if(errno == EINVAL) | |
| 260 fprintf(stderr,"snd_pcm_plugin_write failed EINVAL: %s\n", snd_strerror(written)); | |
| 261 | |
| 262 #endif | |
| 263 | |
| 264 memset(&cstatus, 0, sizeof(cstatus)); | |
| 265 if( (rval = snd_pcm_plugin_status(audio_handle, &cstatus)) < 0 ) | |
| 266 { | |
| 267 #ifdef DEBUG_AUDIO | |
| 268 fprintf(stderr, "snd_pcm_plugin_status failed %s\n",snd_strerror(rval)); | |
| 269 #endif | |
| 270 SDL_SetError("snd_pcm_plugin_status failed: %s\n", snd_strerror(rval)); | |
| 271 return; | |
| 272 } | |
| 273 | |
| 274 if ( (cstatus.status == SND_PCM_STATUS_UNDERRUN) || | |
| 275 (cstatus.status == SND_PCM_STATUS_READY) ) | |
| 276 { | |
| 277 #ifdef DEBUG_AUDIO | |
| 278 fprintf(stderr, "buffer underrun\n"); | |
| 279 #endif | |
| 280 if ( (rval = snd_pcm_plugin_prepare (audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0 ) | |
| 281 { | |
| 282 #ifdef DEBUG_AUDIO | |
| 283 fprintf(stderr, "NTO_PlayAudio: prepare failed %s\n",snd_strerror(rval)); | |
| 284 #endif | |
| 285 SDL_SetError("snd_pcm_plugin_prepare failed: %s\n",snd_strerror(rval) ); | |
| 286 return; | |
| 287 } | |
| 288 | |
| 289 } | |
| 290 continue; | |
| 291 } | |
| 292 else | |
| 293 { | |
| 294 #ifdef DEBUG_AUDIO | |
| 295 fprintf(stderr, "NTO_PlayAudio: snd_pcm_plugin_write failed unknown errno %d %s\n",errno, snd_strerror(rval)); | |
| 296 #endif | |
| 297 return; | |
| 298 | |
| 299 } | |
| 300 | |
| 301 } | |
| 302 else | |
| 303 { | |
| 304 towrite -= written; //we wrote all remaining data | |
| 305 } | |
| 306 } while ( (towrite > 0) && (this->enabled) ); | |
| 307 | |
| 308 /* If we couldn't write, assume fatal error for now */ | |
| 309 if ( towrite != 0 ) { | |
| 310 this->enabled = 0; | |
| 311 } | |
| 312 return; | |
| 313 } | |
| 314 | |
| 315 static Uint8 *NTO_GetAudioBuf(_THIS) | |
| 316 { | |
| 317 #ifdef DEBUG_AUDIO | |
| 318 fprintf(stderr, "NTO_GetAudioBuf: pcm_buf %X\n",(Uint8 *)pcm_buf); | |
| 319 #endif | |
| 320 return(pcm_buf); | |
| 321 } | |
| 322 | |
| 323 static void NTO_CloseAudio(_THIS) | |
| 324 { | |
| 325 int rval; | |
| 326 | |
| 327 #ifdef DEBUG_AUDIO | |
| 328 fprintf(stderr, "NTO_CloseAudio\n"); | |
| 329 #endif | |
| 330 | |
| 331 this->enabled = 0; | |
| 332 | |
| 333 if ( audio_handle != NULL ) { | |
| 334 if ((rval = snd_pcm_plugin_flush(audio_handle,SND_PCM_CHANNEL_PLAYBACK)) < 0) | |
| 335 { | |
| 336 SDL_SetError("snd_pcm_plugin_flush failed: %s\n",snd_strerror(rval)); | |
| 337 return; | |
| 338 } | |
| 339 if ((rval = snd_pcm_close(audio_handle)) < 0) | |
| 340 { | |
| 341 SDL_SetError("snd_pcm_close failed: %s\n",snd_strerror(rval)); | |
| 342 return; | |
| 343 } | |
| 344 audio_handle = NULL; | |
| 345 } | |
| 346 } | |
| 347 | |
| 348 static int NTO_OpenAudio(_THIS, SDL_AudioSpec *spec) | |
| 349 { | |
| 350 int rval; | |
| 351 int format; | |
| 352 Uint16 test_format; | |
| 353 int twidth; | |
| 354 int found; | |
| 355 | |
| 356 #ifdef DEBUG_AUDIO | |
| 357 fprintf(stderr, "NTO_OpenAudio\n"); | |
| 358 #endif | |
| 359 | |
| 360 audio_handle = NULL; | |
| 361 this->enabled = 0; | |
| 362 | |
| 363 if ( pcm_buf != NULL ) { | |
| 364 free((Uint8 *)pcm_buf); | |
| 365 pcm_buf = NULL; | |
| 366 } | |
| 367 | |
| 368 /* initialize channel transfer parameters to default */ | |
| 369 init_pcm_cparams(&cparams); | |
| 370 | |
| 371 /* Open the audio device */ | |
| 372 | |
| 373 rval = snd_pcm_open_preferred(&audio_handle, &card_no, &device_no, OPEN_FLAGS); | |
| 374 if ( rval < 0 ) { | |
| 375 SDL_SetError("snd_pcm_open failed: %s\n", snd_strerror(rval)); | |
| 376 return(-1); | |
| 377 } | |
| 378 | |
| 379 /* set to nonblocking mode */ | |
| 380 if ((rval = snd_pcm_nonblock_mode(audio_handle, 1))<0) //I assume 1 means on | |
| 381 { | |
| 382 SDL_SetError("snd_pcm_nonblock_mode failed: %s\n", snd_strerror(rval)); | |
| 383 return(-1); | |
| 384 } | |
| 385 | |
| 386 /* enable count status parameter */ | |
| 387 if ((rval = snd_plugin_set_disable(audio_handle, PLUGIN_DISABLE_MMAP))<0) | |
| 388 { | |
| 389 SDL_SetError("snd_plugin_set_disable failed: %s\n", snd_strerror(rval)); | |
| 390 return(-1); | |
| 391 } | |
| 392 | |
| 393 | |
| 394 /* Try for a closest match on audio format */ | |
| 395 format = 0; | |
| 396 found = 0; // can't use format as SND_PCM_SFMT_U8 = 0 in nto | |
| 397 for ( test_format = SDL_FirstAudioFormat(spec->format); !found ; ) | |
| 398 | |
| 399 { | |
| 400 #ifdef DEBUG_AUDIO | |
| 401 fprintf(stderr, "Trying format 0x%4.4x spec->samples %d\n", test_format,spec->samples); | |
| 402 #endif | |
| 403 /* if match found set format to equivalent ALSA format */ | |
| 404 switch ( test_format ) { | |
| 405 case AUDIO_U8: | |
| 406 format = SND_PCM_SFMT_U8; | |
| 407 cparams.buf.block.frag_size = spec->samples * spec->channels; | |
| 408 found = 1; | |
| 409 break; | |
| 410 case AUDIO_S8: | |
| 411 format = SND_PCM_SFMT_S8; | |
| 412 cparams.buf.block.frag_size = spec->samples * spec->channels; | |
| 413 found = 1; | |
| 414 break; | |
| 415 case AUDIO_S16LSB: | |
| 416 format = SND_PCM_SFMT_S16_LE; | |
| 417 cparams.buf.block.frag_size = spec->samples*2 * spec->channels; | |
| 418 found = 1; | |
| 419 break; | |
| 420 case AUDIO_S16MSB: | |
| 421 format = SND_PCM_SFMT_S16_BE; | |
| 422 cparams.buf.block.frag_size = spec->samples*2 * spec->channels; | |
| 423 found = 1; | |
| 424 break; | |
| 425 case AUDIO_U16LSB: | |
| 426 format = SND_PCM_SFMT_U16_LE; | |
| 427 cparams.buf.block.frag_size = spec->samples*2 * spec->channels; | |
| 428 found = 1; | |
| 429 break; | |
| 430 case AUDIO_U16MSB: | |
| 431 format = SND_PCM_SFMT_U16_BE; | |
| 432 cparams.buf.block.frag_size = spec->samples*2 * spec->channels; | |
| 433 found = 1; | |
| 434 break; | |
| 435 default: | |
| 436 break; | |
| 437 } | |
| 438 if ( ! found ) { | |
| 439 test_format = SDL_NextAudioFormat(); | |
| 440 } | |
| 441 } | |
| 442 | |
| 443 /* assumes test_format not 0 on success */ | |
| 444 if ( test_format == 0 ) { | |
| 445 SDL_SetError("Couldn't find any hardware audio formats"); | |
| 446 return(-1); | |
| 447 } | |
| 448 | |
| 449 spec->format = test_format; | |
| 450 | |
| 451 /* Set the audio format */ | |
| 452 cparams.format.format = format; | |
| 453 | |
| 454 /* Set mono or stereo audio (currently only two channels supported) */ | |
| 455 cparams.format.voices = spec->channels; | |
| 456 | |
| 457 #ifdef DEBUG_AUDIO | |
| 458 fprintf(stderr,"intializing channels %d\n", cparams.format.voices); | |
| 459 #endif | |
| 460 | |
| 461 | |
| 462 /* Set rate */ | |
| 463 cparams.format.rate = spec->freq ; | |
| 464 | |
| 465 /* Setup the transfer parameters according to cparams */ | |
| 466 rval = snd_pcm_plugin_params(audio_handle, &cparams); | |
| 467 if (rval < 0) { | |
| 468 SDL_SetError("snd_pcm_channel_params failed: %s\n", snd_strerror (rval)); | |
| 469 return(-1); | |
| 470 } | |
| 471 | |
| 472 /* Make sure channel is setup right one last time */ | |
| 473 memset( &csetup, 0, sizeof( csetup ) ); | |
| 474 csetup.channel = SND_PCM_CHANNEL_PLAYBACK; | |
| 475 if ( snd_pcm_plugin_setup( audio_handle, &csetup ) < 0 ) | |
| 476 { | |
| 477 SDL_SetError("Unable to setup playback channel\n" ); | |
| 478 return(-1); | |
| 479 } | |
| 480 else | |
| 481 { | |
| 482 #ifdef DEBUG_AUDIO | |
| 483 fprintf(stderr,"requested format: %d\n",cparams.format.format); | |
| 484 fprintf(stderr,"requested frag size: %d\n",cparams.buf.block.frag_size); | |
| 485 fprintf(stderr,"requested max frags: %d\n\n",cparams.buf.block.frags_max); | |
| 486 | |
| 487 fprintf(stderr,"real format: %d\n", csetup.format.format ); | |
| 488 fprintf(stderr,"real frag size : %d\n", csetup.buf.block.frag_size ); | |
| 489 fprintf(stderr,"real max frags : %d\n", csetup.buf.block.frags_max ); | |
| 490 #endif // DEBUG_AUDIO | |
| 491 } | |
| 492 | |
| 493 | |
| 494 /* Allocate memory to the audio buffer and initialize with silence | |
| 495 (Note that buffer size must be a multiple of fragment size, so find closest multiple) | |
| 496 */ | |
| 497 | |
| 498 twidth = snd_pcm_format_width(format); | |
| 499 if (twidth < 0) { | |
| 500 printf("snd_pcm_format_width failed\n"); | |
| 501 twidth = 0; | |
| 502 } | |
| 503 | |
| 504 #ifdef DEBUG_AUDIO | |
| 505 fprintf(stderr,"format is %d bits wide\n",twidth); | |
| 506 #endif | |
| 507 | |
| 508 pcm_len = spec->size ; | |
| 509 | |
| 510 | |
| 511 #ifdef DEBUG_AUDIO | |
| 512 fprintf(stderr,"pcm_len set to %d\n", pcm_len); | |
| 513 #endif | |
| 514 | |
| 515 if (pcm_len == 0) | |
| 516 { | |
| 517 pcm_len = csetup.buf.block.frag_size; | |
| 518 } | |
| 519 | |
| 520 pcm_buf = (Uint8*)malloc(pcm_len); | |
| 521 if (pcm_buf == NULL) { | |
| 522 SDL_SetError("pcm_buf malloc failed\n"); | |
| 523 return(-1); | |
| 524 } | |
| 525 memset(pcm_buf,spec->silence,pcm_len); | |
| 526 | |
| 527 #ifdef DEBUG_AUDIO | |
| 528 fprintf(stderr,"pcm_buf malloced and silenced.\n"); | |
| 529 #endif | |
| 530 | |
| 531 /* get the file descriptor */ | |
| 532 if( (audio_fd = snd_pcm_file_descriptor(audio_handle, SND_PCM_CHANNEL_PLAYBACK)) < 0) | |
| 533 { | |
| 534 fprintf(stderr, "snd_pcm_file_descriptor failed with error code: %d\n", audio_fd); | |
| 535 } | |
| 536 | |
| 537 /* Trigger audio playback */ | |
| 538 rval = snd_pcm_plugin_prepare( audio_handle, SND_PCM_CHANNEL_PLAYBACK); | |
| 539 if (rval < 0) { | |
| 540 SDL_SetError("snd_pcm_plugin_prepare failed: %s\n", snd_strerror (rval)); | |
| 541 return(-1); | |
| 542 } | |
| 543 | |
| 544 this->enabled = 1; | |
| 545 | |
| 546 /* Get the parent process id (we're the parent of the audio thread) */ | |
| 547 parent = getpid(); | |
| 548 | |
| 549 /* We're ready to rock and roll. :-) */ | |
| 550 return(0); | |
| 551 } | |
| 552 | |
| 553 | |
| 554 |