From f30e120aa9e89e2a3f56e462f0f4d230469739c2 Mon Sep 17 00:00:00 2001 From: "Ryan C. Gordon" Date: Tue, 22 Jul 2014 21:41:49 -0400 Subject: [PATCH] Added audio device buffer queueing API. --- .hgignore | 1 + include/SDL_audio.h | 107 ++++++++++++++- src/audio/SDL_audio.c | 209 ++++++++++++++++++++++++++++-- src/audio/SDL_sysaudio.h | 26 ++++ src/dynapi/SDL_dynapi_overrides.h | 3 + src/dynapi/SDL_dynapi_procs.h | 3 + test/Makefile.in | 4 + test/README | 1 + test/loopwavequeue.c | 127 ++++++++++++++++++ 9 files changed, 469 insertions(+), 12 deletions(-) create mode 100644 test/loopwavequeue.c diff --git a/.hgignore b/.hgignore index e61b7d96a4acf..c16de75952517 100644 --- a/.hgignore +++ b/.hgignore @@ -73,6 +73,7 @@ test/Makefile test/SDL2.dll test/checkkeys test/loopwave +test/loopwavequeue test/testatomic test/testaudioinfo test/testautomation diff --git a/include/SDL_audio.h b/include/SDL_audio.h index 4c987d5110435..5c04b0bf476ee 100644 --- a/include/SDL_audio.h +++ b/include/SDL_audio.h @@ -155,6 +155,9 @@ typedef Uint16 SDL_AudioFormat; * * Once the callback returns, the buffer will no longer be valid. * Stereo samples are stored in a LRLRLR ordering. + * + * You can choose to avoid callbacks and use SDL_QueueAudio() instead, if + * you like. Just open your audio device with a NULL callback. */ typedef void (SDLCALL * SDL_AudioCallback) (void *userdata, Uint8 * stream, int len); @@ -171,8 +174,8 @@ typedef struct SDL_AudioSpec Uint16 samples; /**< Audio buffer size in samples (power of 2) */ Uint16 padding; /**< Necessary for some compile environments */ Uint32 size; /**< Audio buffer size in bytes (calculated) */ - SDL_AudioCallback callback; - void *userdata; + SDL_AudioCallback callback; /**< Callback that feeds the audio device (NULL to use SDL_QueueAudio()). */ + void *userdata; /**< Userdata passed to callback (ignored for NULL callbacks). */ } SDL_AudioSpec; @@ -273,9 +276,11 @@ extern DECLSPEC const char *SDLCALL SDL_GetCurrentAudioDriver(void); * to the audio buffer, and the length in bytes of the audio buffer. * This function usually runs in a separate thread, and so you should * protect data structures that it accesses by calling SDL_LockAudio() - * and SDL_UnlockAudio() in your code. + * and SDL_UnlockAudio() in your code. Alternately, you may pass a NULL + * pointer here, and call SDL_QueueAudio() with some frequency, to queue + * more audio samples to be played. * - \c desired->userdata is passed as the first parameter to your callback - * function. + * function. If you passed a NULL callback, this value is ignored. * * The audio device starts out playing silence when it's opened, and should * be enabled for playing by calling \c SDL_PauseAudio(0) when you are ready @@ -474,6 +479,100 @@ extern DECLSPEC void SDLCALL SDL_MixAudioFormat(Uint8 * dst, SDL_AudioFormat format, Uint32 len, int volume); +/** + * Queue more audio on non-callback devices. + * + * SDL offers two ways to feed audio to the device: you can either supply a + * callback that SDL triggers with some frequency to obtain more audio + * (pull method), or you can supply no callback, and then SDL will expect + * you to supply data at regular intervals (push method) with this function. + * + * There are no limits on the amount of data you can queue, short of + * exhaustion of address space. Queued data will drain to the device as + * necessary without further intervention from you. If the device needs + * audio but there is not enough queued, it will play silence to make up + * the difference. This means you will have skips in your audio playback + * if you aren't routinely queueing sufficient data. + * + * This function copies the supplied data, so you are safe to free it when + * the function returns. This function is thread-safe, but queueing to the + * same device from two threads at once does not promise which buffer will + * be queued first. + * + * You may not queue audio on a device that is using an application-supplied + * callback; doing so returns an error. You have to use the audio callback + * or queue audio with this function, but not both. + * + * You should not call SDL_LockAudio() on the device before queueing; SDL + * handles locking internally for this function. + * + * \param dev The device ID to which we will queue audio. + * \param data The data to queue to the device for later playback. + * \param len The number of bytes (not samples!) to which (data) points. + * \return zero on success, -1 on error. + * + * \sa SDL_GetQueuedAudioSize + * \sa SDL_ClearQueuedAudio + */ +extern DECLSPEC int SDLCALL SDL_QueueAudio(SDL_AudioDeviceID dev, const void *data, Uint32 len); + +/** + * Get the number of bytes of still-queued audio. + * + * This is the number of bytes that have been queued for playback with + * SDL_QueueAudio(), but have not yet been sent to the hardware. + * + * Once we've sent it to the hardware, this function can not decide the exact + * byte boundary of what has been played. It's possible that we just gave the + * hardware several kilobytes right before you called this function, but it + * hasn't played any of it yet, or maybe half of it, etc. + * + * You may not queue audio on a device that is using an application-supplied + * callback; calling this function on such a device always returns 0. + * You have to use the audio callback or queue audio with SDL_QueueAudio(), + * but not both. + * + * You should not call SDL_LockAudio() on the device before querying; SDL + * handles locking internally for this function. + * + * \param dev The device ID of which we will query queued audio size. + * \return Number of bytes (not samples!) of queued audio. + * + * \sa SDL_QueueAudio + * \sa SDL_ClearQueuedAudio + */ +extern DECLSPEC Uint32 SDLCALL SDL_GetQueuedAudioSize(SDL_AudioDeviceID dev); + +/** + * Drop any queued audio data waiting to be sent to the hardware. + * + * Immediately after this call, SDL_GetQueuedAudioSize() will return 0 and + * the hardware will start playing silence if more audio isn't queued. + * + * This will not prevent playback of queued audio that's already been sent + * to the hardware, as we can not undo that, so expect there to be some + * fraction of a second of audio that might still be heard. This can be + * useful if you want to, say, drop any pending music during a level change + * in your game. + * + * You may not queue audio on a device that is using an application-supplied + * callback; calling this function on such a device is always a no-op. + * You have to use the audio callback or queue audio with SDL_QueueAudio(), + * but not both. + * + * You should not call SDL_LockAudio() on the device before clearing the + * queue; SDL handles locking internally for this function. + * + * This function always succeeds and thus returns void. + * + * \param dev The device ID of which to clear the audio queue. + * + * \sa SDL_QueueAudio + * \sa SDL_GetQueuedAudioSize + */ +extern DECLSPEC void SDLCALL SDL_ClearQueuedAudio(SDL_AudioDeviceID dev); + + /** * \name Audio lock functions * diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c index 8791d29ec7f4b..a788c89a2de83 100644 --- a/src/audio/SDL_audio.c +++ b/src/audio/SDL_audio.c @@ -324,6 +324,181 @@ SDL_StreamDeinit(SDL_AudioStreamer * stream) } #endif + +/* buffer queueing support... */ + +/* this expects that you managed thread safety elsewhere. */ +static void +free_audio_queue(SDL_AudioBufferQueue *buffer) +{ + while (buffer) { + SDL_AudioBufferQueue *next = buffer->next; + SDL_free(buffer); + buffer = next; + } +} + +static void SDLCALL +SDL_BufferQueueDrainCallback(void *userdata, Uint8 *stream, int _len) +{ + /* this function always holds the mixer lock before being called. */ + Uint32 len = (Uint32) _len; + SDL_AudioDevice *device = (SDL_AudioDevice *) userdata; + SDL_AudioBufferQueue *buffer; + + SDL_assert(device != NULL); /* this shouldn't ever happen, right?! */ + SDL_assert(_len >= 0); /* this shouldn't ever happen, right?! */ + + while ((len > 0) && ((buffer = device->buffer_queue_head) != NULL)) { + const Uint32 avail = buffer->datalen - buffer->startpos; + const Uint32 cpy = SDL_min(len, avail); + SDL_assert(device->queued_bytes >= avail); + + SDL_memcpy(stream, buffer->data + buffer->startpos, cpy); + buffer->startpos += cpy; + stream += cpy; + device->queued_bytes -= cpy; + len -= cpy; + + if (buffer->startpos == buffer->datalen) { /* packet is done, put it in the pool. */ + device->buffer_queue_head = buffer->next; + SDL_assert((buffer->next != NULL) || (buffer == device->buffer_queue_tail)); + buffer->next = device->buffer_queue_pool; + device->buffer_queue_pool = buffer; + } + } + + SDL_assert((device->buffer_queue_head != NULL) == (device->queued_bytes != 0)); + + if (len > 0) { /* fill any remaining space in the stream with silence. */ + SDL_assert(device->buffer_queue_head == NULL); + SDL_memset(stream, device->spec.silence, len); + } + + if (device->buffer_queue_head == NULL) { + device->buffer_queue_tail = NULL; /* in case we drained the queue entirely. */ + } +} + +int +SDL_QueueAudio(SDL_AudioDeviceID devid, const void *_data, Uint32 len) +{ + SDL_AudioDevice *device = get_audio_device(devid); + const Uint8 *data = (const Uint8 *) _data; + SDL_AudioBufferQueue *orighead; + SDL_AudioBufferQueue *origtail; + Uint32 origlen; + Uint32 datalen; + + if (!device) { + return -1; /* get_audio_device() will have set the error state */ + } + + if (device->spec.callback != SDL_BufferQueueDrainCallback) { + return SDL_SetError("Audio device has a callback, queueing not allowed"); + } + + current_audio.impl.LockDevice(device); + + orighead = device->buffer_queue_head; + origtail = device->buffer_queue_tail; + origlen = origtail ? origtail->datalen : 0; + + while (len > 0) { + SDL_AudioBufferQueue *packet = device->buffer_queue_tail; + SDL_assert(!packet || (packet->datalen <= SDL_AUDIOBUFFERQUEUE_PACKETLEN)); + if (!packet || (packet->datalen >= SDL_AUDIOBUFFERQUEUE_PACKETLEN)) { + /* tail packet missing or completely full; we need a new packet. */ + packet = device->buffer_queue_pool; + if (packet != NULL) { + /* we have one available in the pool. */ + device->buffer_queue_pool = packet->next; + } else { + /* Have to allocate a new one! */ + packet = (SDL_AudioBufferQueue *) SDL_malloc(sizeof (SDL_AudioBufferQueue)); + if (packet == NULL) { + /* uhoh, reset so we've queued nothing new, free what we can. */ + if (!origtail) { + packet = device->buffer_queue_head; /* whole queue. */ + } else { + packet = origtail->next; /* what we added to existing queue. */ + origtail->next = NULL; + origtail->datalen = origlen; + } + device->buffer_queue_head = orighead; + device->buffer_queue_tail = origtail; + device->buffer_queue_pool = NULL; + + current_audio.impl.UnlockDevice(device); + + free_audio_queue(packet); /* give back what we can. */ + + return SDL_OutOfMemory(); + } + } + packet->datalen = 0; + packet->startpos = 0; + packet->next = NULL; + + SDL_assert((device->buffer_queue_head != NULL) == (device->queued_bytes != 0)); + if (device->buffer_queue_tail == NULL) { + device->buffer_queue_head = packet; + } else { + device->buffer_queue_tail->next = packet; + } + device->buffer_queue_tail = packet; + } + + datalen = SDL_min(len, SDL_AUDIOBUFFERQUEUE_PACKETLEN - packet->datalen); + SDL_memcpy(packet->data + packet->datalen, data, datalen); + data += datalen; + len -= datalen; + packet->datalen += datalen; + device->queued_bytes += datalen; + } + + current_audio.impl.UnlockDevice(device); + + return 0; +} + +Uint32 +SDL_GetQueuedAudioSize(SDL_AudioDeviceID devid) +{ + /* this happens to work for non-queueing devices, since we memset() + the device to zero at init time, and these devices should return 0. */ + Uint32 retval = 0; + SDL_AudioDevice *device = get_audio_device(devid); + if (device) { + current_audio.impl.LockDevice(device); + retval = device->queued_bytes; + current_audio.impl.UnlockDevice(device); + } + + return retval; +} + +void +SDL_ClearQueuedAudio(SDL_AudioDeviceID devid) +{ + SDL_AudioDevice *device = get_audio_device(devid); + SDL_AudioBufferQueue *buffer = NULL; + if (!device) { + return; /* nothing to do. */ + } + + /* Blank out the device and release the mutex. Free it afterwards. */ + current_audio.impl.LockDevice(device); + buffer = device->buffer_queue_head; + device->buffer_queue_tail = NULL; + device->buffer_queue_head = NULL; + device->queued_bytes = 0; + current_audio.impl.UnlockDevice(device); + + free_audio_queue(buffer); +} + + #if defined(__ANDROID__) #include #endif @@ -800,6 +975,10 @@ close_audio_device(SDL_AudioDevice * device) current_audio.impl.CloseDevice(device); device->opened = 0; } + + free_audio_queue(device->buffer_queue_head); + free_audio_queue(device->buffer_queue_pool); + SDL_FreeAudioMem(device); } @@ -814,11 +993,6 @@ prepare_audiospec(const SDL_AudioSpec * orig, SDL_AudioSpec * prepared) { SDL_memcpy(prepared, orig, sizeof(SDL_AudioSpec)); - if (orig->callback == NULL) { - SDL_SetError("SDL_OpenAudio() passed a NULL callback"); - return 0; - } - if (orig->freq == 0) { const char *env = SDL_getenv("SDL_AUDIO_FREQUENCY"); if ((!env) || ((prepared->freq = SDL_atoi(env)) == 0)) { @@ -871,7 +1045,6 @@ prepare_audiospec(const SDL_AudioSpec * orig, SDL_AudioSpec * prepared) return 1; } - static SDL_AudioDeviceID open_audio_device(const char *devname, int iscapture, const SDL_AudioSpec * desired, SDL_AudioSpec * obtained, @@ -950,7 +1123,7 @@ open_audio_device(const char *devname, int iscapture, SDL_OutOfMemory(); return 0; } - SDL_memset(device, '\0', sizeof(SDL_AudioDevice)); + SDL_zerop(device); device->spec = *obtained; device->enabled = 1; device->paused = 1; @@ -968,8 +1141,9 @@ open_audio_device(const char *devname, int iscapture, /* force a device detection if we haven't done one yet. */ if ( ((iscapture) && (current_audio.inputDevices == NULL)) || - ((!iscapture) && (current_audio.outputDevices == NULL)) ) + ((!iscapture) && (current_audio.outputDevices == NULL)) ) { SDL_GetNumAudioDevices(iscapture); + } if (current_audio.impl.OpenDevice(device, devname, iscapture) < 0) { close_audio_device(device); @@ -1043,6 +1217,25 @@ open_audio_device(const char *devname, int iscapture, } } + if (device->spec.callback == NULL) { /* use buffer queueing? */ + /* pool a few packets to start. Enough for two callbacks. */ + const int packetlen = SDL_AUDIOBUFFERQUEUE_PACKETLEN; + const int wantbytes = ((device->convert.needed) ? device->convert.len : device->spec.size) * 2; + const int wantpackets = (wantbytes / packetlen) + ((wantbytes % packetlen) ? packetlen : 0); + for (i = 0; i < wantpackets; i++) { + SDL_AudioBufferQueue *packet = (SDL_AudioBufferQueue *) SDL_malloc(sizeof (SDL_AudioBufferQueue)); + if (packet) { /* don't care if this fails, we'll deal later. */ + packet->datalen = 0; + packet->startpos = 0; + packet->next = device->buffer_queue_pool; + device->buffer_queue_pool = packet; + } + } + + device->spec.callback = SDL_BufferQueueDrainCallback; + device->spec.userdata = device; + } + /* Find an available device ID and store the structure... */ for (id = min_id - 1; id < SDL_arraysize(open_devices); id++) { if (open_devices[id] == NULL) { diff --git a/src/audio/SDL_sysaudio.h b/src/audio/SDL_sysaudio.h index 9fe31c807ea24..c1810b4326647 100644 --- a/src/audio/SDL_sysaudio.h +++ b/src/audio/SDL_sysaudio.h @@ -33,6 +33,26 @@ typedef struct SDL_AudioDevice SDL_AudioDevice; /* Used by audio targets during DetectDevices() */ typedef void (*SDL_AddAudioDevice)(const char *name); +/* This is the size of a packet when using SDL_QueueAudio(). We allocate + these as necessary and pool them, under the assumption that we'll + eventually end up with a handful that keep recycling, meeting whatever + the app needs. We keep packing data tightly as more arrives to avoid + wasting space, and if we get a giant block of data, we'll split them + into multiple packets behind the scenes. My expectation is that most + apps will have 2-3 of these in the pool. 8k should cover most needs, but + if this is crippling for some embedded system, we can #ifdef this. + The system preallocates enough packets for 2 callbacks' worth of data. */ +#define SDL_AUDIOBUFFERQUEUE_PACKETLEN (8 * 1024) + +/* Used by apps that queue audio instead of using the callback. */ +typedef struct SDL_AudioBufferQueue +{ + Uint8 data[SDL_AUDIOBUFFERQUEUE_PACKETLEN]; /* packet data. */ + Uint32 datalen; /* bytes currently in use in this packet. */ + Uint32 startpos; /* bytes currently consumed in this packet. */ + struct SDL_AudioBufferQueue *next; /* next item in linked list. */ +} SDL_AudioBufferQueue; + typedef struct SDL_AudioDriverImpl { void (*DetectDevices) (int iscapture, SDL_AddAudioDevice addfn); @@ -119,6 +139,12 @@ struct SDL_AudioDevice SDL_Thread *thread; SDL_threadID threadid; + /* Queued buffers (if app not using callback). */ + SDL_AudioBufferQueue *buffer_queue_head; /* device fed from here. */ + SDL_AudioBufferQueue *buffer_queue_tail; /* queue fills to here. */ + SDL_AudioBufferQueue *buffer_queue_pool; /* these are unused packets. */ + Uint32 queued_bytes; /* number of bytes of audio data in the queue. */ + /* * * */ /* Data private to this driver */ struct SDL_PrivateAudioData *hidden; diff --git a/src/dynapi/SDL_dynapi_overrides.h b/src/dynapi/SDL_dynapi_overrides.h index 79d6e8ba3fbdd..8bcde6312d33e 100644 --- a/src/dynapi/SDL_dynapi_overrides.h +++ b/src/dynapi/SDL_dynapi_overrides.h @@ -588,3 +588,6 @@ #define SDL_SetWindowHitTest SDL_SetWindowHitTest_REAL #define SDL_GetGlobalMouseState SDL_GetGlobalMouseState_REAL #define SDL_HasAVX2 SDL_HasAVX2_REAL +#define SDL_QueueAudio SDL_QueueAudio_REAL +#define SDL_GetQueuedAudioSize SDL_GetQueuedAudioSize_REAL +#define SDL_ClearQueuedAudio SDL_ClearQueuedAudio_REAL diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h index 0112769407737..c41cdc9f027c0 100644 --- a/src/dynapi/SDL_dynapi_procs.h +++ b/src/dynapi/SDL_dynapi_procs.h @@ -620,3 +620,6 @@ SDL_DYNAPI_PROC(int,SDL_CaptureMouse,(SDL_bool a),(a),return) SDL_DYNAPI_PROC(int,SDL_SetWindowHitTest,(SDL_Window *a, SDL_HitTest b, void *c),(a,b,c),return) SDL_DYNAPI_PROC(Uint32,SDL_GetGlobalMouseState,(int *a, int *b),(a,b),return) SDL_DYNAPI_PROC(SDL_bool,SDL_HasAVX2,(void),(),return) +SDL_DYNAPI_PROC(int,SDL_QueueAudio,(SDL_AudioDeviceID a, const void *b, Uint32 c),(a,b,c),return) +SDL_DYNAPI_PROC(Uint32,SDL_GetQueuedAudioSize,(SDL_AudioDeviceID a),(a),return) +SDL_DYNAPI_PROC(void,SDL_ClearQueuedAudio,(SDL_AudioDeviceID a),(a),) diff --git a/test/Makefile.in b/test/Makefile.in index bc988556d13ee..79edbc31afe2f 100644 --- a/test/Makefile.in +++ b/test/Makefile.in @@ -10,6 +10,7 @@ LIBS = @LIBS@ TARGETS = \ checkkeys$(EXE) \ loopwave$(EXE) \ + loopwavequeue$(EXE) \ testatomic$(EXE) \ testaudioinfo$(EXE) \ testautomation$(EXE) \ @@ -71,6 +72,9 @@ checkkeys$(EXE): $(srcdir)/checkkeys.c loopwave$(EXE): $(srcdir)/loopwave.c $(CC) -o $@ $^ $(CFLAGS) $(LIBS) +loopwavequeue$(EXE): $(srcdir)/loopwavequeue.c + $(CC) -o $@ $^ $(CFLAGS) $(LIBS) + testresample$(EXE): $(srcdir)/testresample.c $(CC) -o $@ $^ $(CFLAGS) $(LIBS) diff --git a/test/README b/test/README index b820a88d7a92d..6ce361674dfc8 100644 --- a/test/README +++ b/test/README @@ -3,6 +3,7 @@ These are test programs for the SDL library: checkkeys Watch the key events to check the keyboard loopwave Audio test -- loop playing a WAV file + loopwavequeue Audio test -- loop playing a WAV file with SDL_QueueAudio testaudioinfo Lists audio device capabilities testcdrom Sample audio CD control program testerror Tests multi-threaded error handling diff --git a/test/loopwavequeue.c b/test/loopwavequeue.c new file mode 100644 index 0000000000000..a70e516dd6d6d --- /dev/null +++ b/test/loopwavequeue.c @@ -0,0 +1,127 @@ +/* + Copyright (C) 1997-2014 Sam Lantinga + + This software is provided 'as-is', without any express or implied + warranty. In no event will the authors be held liable for any damages + arising from the use of this software. + + Permission is granted to anyone to use this software for any purpose, + including commercial applications, and to alter it and redistribute it + freely. +*/ + +/* Program to load a wave file and loop playing it using SDL sound queueing */ + +#include +#include + +#if HAVE_SIGNAL_H +#include +#endif + +#include "SDL.h" + +struct +{ + SDL_AudioSpec spec; + Uint8 *sound; /* Pointer to wave data */ + Uint32 soundlen; /* Length of wave data */ + int soundpos; /* Current play position */ +} wave; + + +/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ +static void +quit(int rc) +{ + SDL_Quit(); + exit(rc); +} + +static int done = 0; +void +poked(int sig) +{ + done = 1; +} + +int +main(int argc, char *argv[]) +{ + int i; + char filename[4096]; + + /* Enable standard application logging */ + SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO); + + /* Load the SDL library */ + if (SDL_Init(SDL_INIT_AUDIO) < 0) { + SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError()); + return (1); + } + + if (argc > 1) { + SDL_strlcpy(filename, argv[1], sizeof(filename)); + } else { + SDL_strlcpy(filename, "sample.wav", sizeof(filename)); + } + /* Load the wave file into memory */ + if (SDL_LoadWAV(filename, &wave.spec, &wave.sound, &wave.soundlen) == NULL) { + SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load %s: %s\n", filename, SDL_GetError()); + quit(1); + } + + wave.spec.callback = NULL; /* we'll push audio. */ + +#if HAVE_SIGNAL_H + /* Set the signals */ +#ifdef SIGHUP + signal(SIGHUP, poked); +#endif + signal(SIGINT, poked); +#ifdef SIGQUIT + signal(SIGQUIT, poked); +#endif + signal(SIGTERM, poked); +#endif /* HAVE_SIGNAL_H */ + + /* Initialize fillerup() variables */ + if (SDL_OpenAudio(&wave.spec, NULL) < 0) { + SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open audio: %s\n", SDL_GetError()); + SDL_FreeWAV(wave.sound); + quit(2); + } + + /*static x[99999]; SDL_QueueAudio(1, x, sizeof (x));*/ + + /* Let the audio run */ + SDL_PauseAudio(0); + + /* Note that we stuff the entire audio buffer into the queue in one + shot. Most apps would want to feed it a little at a time, as it + plays, but we're going for simplicity here. */ + + while (!done && (SDL_GetAudioStatus() == SDL_AUDIO_PLAYING)) + { + /* The device from SDL_OpenAudio() is always device #1. */ + const Uint32 queued = SDL_GetQueuedAudioSize(1); + SDL_Log("Device has %u bytes queued.\n", (unsigned int) queued); + if (queued <= 8192) { /* time to requeue the whole thing? */ + if (SDL_QueueAudio(1, wave.sound, wave.soundlen) == 0) { + SDL_Log("Device queued %u more bytes.\n", (unsigned int) wave.soundlen); + } else { + SDL_Log("Device FAILED to queue %u more bytes: %s\n", (unsigned int) wave.soundlen, SDL_GetError()); + } + } + + SDL_Delay(100); /* let it play for awhile. */ + } + + /* Clean up on signal */ + SDL_CloseAudio(); + SDL_FreeWAV(wave.sound); + SDL_Quit(); + return 0; +} + +/* vi: set ts=4 sw=4 expandtab: */