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comparison src/audio/alsa/SDL_alsa_audio.c @ 1702:a7ad7081b977 SDL-1.3

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Merged Ryan's 5.1 audio fix from SDL 1.2
author Sam Lantinga <slouken@libsdl.org>
date Fri, 23 Jun 2006 09:01:08 +0000
parents 4da1ee79c9af
children
comparison
equal deleted inserted replaced
1701:442248d4e738 1702:a7ad7081b977
349 } 349 }
350 } 350 }
351 } 351 }
352 } 352 }
353 353
354
355 /*
356 * http://bugzilla.libsdl.org/show_bug.cgi?id=110
357 * "For Linux ALSA, this is FL-FR-RL-RR-C-LFE
358 * and for Windows DirectX [and CoreAudio], this is FL-FR-C-LFE-RL-RR"
359 */
360 #define SWIZ6(T) \
361 T *ptr = (T *) mixbuf; \
362 const Uint32 count = (this->spec.samples / 6); \
363 Uint32 i; \
364 for (i = 0; i < count; i++, ptr += 6) { \
365 T tmp; \
366 tmp = ptr[2]; ptr[2] = ptr[4]; ptr[4] = tmp; \
367 tmp = ptr[3]; ptr[3] = ptr[5]; ptr[5] = tmp; \
368 }
369
370 static __inline__ void
371 swizzle_alsa_channels_6_64bit(_THIS)
372 {
373 SWIZ6(Uint64);
374 }
375 static __inline__ void
376 swizzle_alsa_channels_6_32bit(_THIS)
377 {
378 SWIZ6(Uint32);
379 }
380 static __inline__ void
381 swizzle_alsa_channels_6_16bit(_THIS)
382 {
383 SWIZ6(Uint16);
384 }
385 static __inline__ void
386 swizzle_alsa_channels_6_8bit(_THIS)
387 {
388 SWIZ6(Uint8);
389 }
390
391 #undef SWIZ6
392
393
394 /*
395 * Called right before feeding this->mixbuf to the hardware. Swizzle channels
396 * from Windows/Mac order to the format alsalib will want.
397 */
398 static __inline__ void
399 swizzle_alsa_channels(_THIS)
400 {
401 if (this->spec.channels == 6) {
402 const Uint16 fmtsize = (this->spec.format & 0xFF); /* bits/channel. */
403 if (fmtsize == 16)
404 swizzle_alsa_channels_6_16bit(this);
405 else if (fmtsize == 8)
406 swizzle_alsa_channels_6_8bit(this);
407 else if (fmtsize == 32)
408 swizzle_alsa_channels_6_32bit(this);
409 else if (fmtsize == 64)
410 swizzle_alsa_channels_6_64bit(this);
411 }
412
413 /* !!! FIXME: update this for 7.1 if needed, later. */
414 }
415
416
354 static void 417 static void
355 ALSA_PlayAudio(_THIS) 418 ALSA_PlayAudio(_THIS)
356 { 419 {
357 int status; 420 int status;
358 int sample_len; 421 int sample_len;
359 signed short *sample_buf; 422 signed short *sample_buf;
360 423
424 swizzle_alsa_channels(this);
425
361 sample_len = this->spec.samples; 426 sample_len = this->spec.samples;
362 sample_buf = (signed short *) mixbuf; 427 sample_buf = (signed short *) mixbuf;
428
363 while (sample_len > 0) { 429 while (sample_len > 0) {
364 status = 430 status =
365 SDL_NAME(snd_pcm_writei) (pcm_handle, sample_buf, sample_len); 431 SDL_NAME(snd_pcm_writei) (pcm_handle, sample_buf, sample_len);
366 if (status < 0) { 432 if (status < 0) {
367 if (status == -EAGAIN) { 433 if (status == -EAGAIN) {
370 } 436 }
371 if (status == -ESTRPIPE) { 437 if (status == -ESTRPIPE) {
372 do { 438 do {
373 SDL_Delay(1); 439 SDL_Delay(1);
374 status = SDL_NAME(snd_pcm_resume) (pcm_handle); 440 status = SDL_NAME(snd_pcm_resume) (pcm_handle);
375 } 441 } while (status == -EAGAIN);
376 while (status == -EAGAIN);
377 } 442 }
378 if (status < 0) { 443 if (status < 0) {
379 status = SDL_NAME(snd_pcm_prepare) (pcm_handle); 444 status = SDL_NAME(snd_pcm_prepare) (pcm_handle);
380 } 445 }
381 if (status < 0) { 446 if (status < 0) {