cscg22-gearboy

CSCG 2022 Challenge 'Gearboy'
git clone https://git.sinitax.com/sinitax/cscg22-gearboy
Log | Files | Refs | sfeed.txt

SDL_audio.h (24736B)


      1/*
      2  Simple DirectMedia Layer
      3  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
      4
      5  This software is provided 'as-is', without any express or implied
      6  warranty.  In no event will the authors be held liable for any damages
      7  arising from the use of this software.
      8
      9  Permission is granted to anyone to use this software for any purpose,
     10  including commercial applications, and to alter it and redistribute it
     11  freely, subject to the following restrictions:
     12
     13  1. The origin of this software must not be misrepresented; you must not
     14     claim that you wrote the original software. If you use this software
     15     in a product, an acknowledgment in the product documentation would be
     16     appreciated but is not required.
     17  2. Altered source versions must be plainly marked as such, and must not be
     18     misrepresented as being the original software.
     19  3. This notice may not be removed or altered from any source distribution.
     20*/
     21
     22/**
     23 *  \file SDL_audio.h
     24 *
     25 *  Access to the raw audio mixing buffer for the SDL library.
     26 */
     27
     28#ifndef _SDL_audio_h
     29#define _SDL_audio_h
     30
     31#include "SDL_stdinc.h"
     32#include "SDL_error.h"
     33#include "SDL_endian.h"
     34#include "SDL_mutex.h"
     35#include "SDL_thread.h"
     36#include "SDL_rwops.h"
     37
     38#include "begin_code.h"
     39/* Set up for C function definitions, even when using C++ */
     40#ifdef __cplusplus
     41extern "C" {
     42#endif
     43
     44/**
     45 *  \brief Audio format flags.
     46 *
     47 *  These are what the 16 bits in SDL_AudioFormat currently mean...
     48 *  (Unspecified bits are always zero).
     49 *
     50 *  \verbatim
     51    ++-----------------------sample is signed if set
     52    ||
     53    ||       ++-----------sample is bigendian if set
     54    ||       ||
     55    ||       ||          ++---sample is float if set
     56    ||       ||          ||
     57    ||       ||          || +---sample bit size---+
     58    ||       ||          || |                     |
     59    15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
     60    \endverbatim
     61 *
     62 *  There are macros in SDL 2.0 and later to query these bits.
     63 */
     64typedef Uint16 SDL_AudioFormat;
     65
     66/**
     67 *  \name Audio flags
     68 */
     69/* @{ */
     70
     71#define SDL_AUDIO_MASK_BITSIZE       (0xFF)
     72#define SDL_AUDIO_MASK_DATATYPE      (1<<8)
     73#define SDL_AUDIO_MASK_ENDIAN        (1<<12)
     74#define SDL_AUDIO_MASK_SIGNED        (1<<15)
     75#define SDL_AUDIO_BITSIZE(x)         (x & SDL_AUDIO_MASK_BITSIZE)
     76#define SDL_AUDIO_ISFLOAT(x)         (x & SDL_AUDIO_MASK_DATATYPE)
     77#define SDL_AUDIO_ISBIGENDIAN(x)     (x & SDL_AUDIO_MASK_ENDIAN)
     78#define SDL_AUDIO_ISSIGNED(x)        (x & SDL_AUDIO_MASK_SIGNED)
     79#define SDL_AUDIO_ISINT(x)           (!SDL_AUDIO_ISFLOAT(x))
     80#define SDL_AUDIO_ISLITTLEENDIAN(x)  (!SDL_AUDIO_ISBIGENDIAN(x))
     81#define SDL_AUDIO_ISUNSIGNED(x)      (!SDL_AUDIO_ISSIGNED(x))
     82
     83/**
     84 *  \name Audio format flags
     85 *
     86 *  Defaults to LSB byte order.
     87 */
     88/* @{ */
     89#define AUDIO_U8        0x0008  /**< Unsigned 8-bit samples */
     90#define AUDIO_S8        0x8008  /**< Signed 8-bit samples */
     91#define AUDIO_U16LSB    0x0010  /**< Unsigned 16-bit samples */
     92#define AUDIO_S16LSB    0x8010  /**< Signed 16-bit samples */
     93#define AUDIO_U16MSB    0x1010  /**< As above, but big-endian byte order */
     94#define AUDIO_S16MSB    0x9010  /**< As above, but big-endian byte order */
     95#define AUDIO_U16       AUDIO_U16LSB
     96#define AUDIO_S16       AUDIO_S16LSB
     97/* @} */
     98
     99/**
    100 *  \name int32 support
    101 */
    102/* @{ */
    103#define AUDIO_S32LSB    0x8020  /**< 32-bit integer samples */
    104#define AUDIO_S32MSB    0x9020  /**< As above, but big-endian byte order */
    105#define AUDIO_S32       AUDIO_S32LSB
    106/* @} */
    107
    108/**
    109 *  \name float32 support
    110 */
    111/* @{ */
    112#define AUDIO_F32LSB    0x8120  /**< 32-bit floating point samples */
    113#define AUDIO_F32MSB    0x9120  /**< As above, but big-endian byte order */
    114#define AUDIO_F32       AUDIO_F32LSB
    115/* @} */
    116
    117/**
    118 *  \name Native audio byte ordering
    119 */
    120/* @{ */
    121#if SDL_BYTEORDER == SDL_LIL_ENDIAN
    122#define AUDIO_U16SYS    AUDIO_U16LSB
    123#define AUDIO_S16SYS    AUDIO_S16LSB
    124#define AUDIO_S32SYS    AUDIO_S32LSB
    125#define AUDIO_F32SYS    AUDIO_F32LSB
    126#else
    127#define AUDIO_U16SYS    AUDIO_U16MSB
    128#define AUDIO_S16SYS    AUDIO_S16MSB
    129#define AUDIO_S32SYS    AUDIO_S32MSB
    130#define AUDIO_F32SYS    AUDIO_F32MSB
    131#endif
    132/* @} */
    133
    134/**
    135 *  \name Allow change flags
    136 *
    137 *  Which audio format changes are allowed when opening a device.
    138 */
    139/* @{ */
    140#define SDL_AUDIO_ALLOW_FREQUENCY_CHANGE    0x00000001
    141#define SDL_AUDIO_ALLOW_FORMAT_CHANGE       0x00000002
    142#define SDL_AUDIO_ALLOW_CHANNELS_CHANGE     0x00000004
    143#define SDL_AUDIO_ALLOW_ANY_CHANGE          (SDL_AUDIO_ALLOW_FREQUENCY_CHANGE|SDL_AUDIO_ALLOW_FORMAT_CHANGE|SDL_AUDIO_ALLOW_CHANNELS_CHANGE)
    144/* @} */
    145
    146/* @} *//* Audio flags */
    147
    148/**
    149 *  This function is called when the audio device needs more data.
    150 *
    151 *  \param userdata An application-specific parameter saved in
    152 *                  the SDL_AudioSpec structure
    153 *  \param stream A pointer to the audio data buffer.
    154 *  \param len    The length of that buffer in bytes.
    155 *
    156 *  Once the callback returns, the buffer will no longer be valid.
    157 *  Stereo samples are stored in a LRLRLR ordering.
    158 *
    159 *  You can choose to avoid callbacks and use SDL_QueueAudio() instead, if
    160 *  you like. Just open your audio device with a NULL callback.
    161 */
    162typedef void (SDLCALL * SDL_AudioCallback) (void *userdata, Uint8 * stream,
    163                                            int len);
    164
    165/**
    166 *  The calculated values in this structure are calculated by SDL_OpenAudio().
    167 */
    168typedef struct SDL_AudioSpec
    169{
    170    int freq;                   /**< DSP frequency -- samples per second */
    171    SDL_AudioFormat format;     /**< Audio data format */
    172    Uint8 channels;             /**< Number of channels: 1 mono, 2 stereo */
    173    Uint8 silence;              /**< Audio buffer silence value (calculated) */
    174    Uint16 samples;             /**< Audio buffer size in samples (power of 2) */
    175    Uint16 padding;             /**< Necessary for some compile environments */
    176    Uint32 size;                /**< Audio buffer size in bytes (calculated) */
    177    SDL_AudioCallback callback; /**< Callback that feeds the audio device (NULL to use SDL_QueueAudio()). */
    178    void *userdata;             /**< Userdata passed to callback (ignored for NULL callbacks). */
    179} SDL_AudioSpec;
    180
    181
    182struct SDL_AudioCVT;
    183typedef void (SDLCALL * SDL_AudioFilter) (struct SDL_AudioCVT * cvt,
    184                                          SDL_AudioFormat format);
    185
    186/**
    187 *  A structure to hold a set of audio conversion filters and buffers.
    188 */
    189#ifdef __GNUC__
    190/* This structure is 84 bytes on 32-bit architectures, make sure GCC doesn't
    191   pad it out to 88 bytes to guarantee ABI compatibility between compilers.
    192   vvv
    193   The next time we rev the ABI, make sure to size the ints and add padding.
    194*/
    195#define SDL_AUDIOCVT_PACKED __attribute__((packed))
    196#else
    197#define SDL_AUDIOCVT_PACKED
    198#endif
    199/* */
    200typedef struct SDL_AudioCVT
    201{
    202    int needed;                 /**< Set to 1 if conversion possible */
    203    SDL_AudioFormat src_format; /**< Source audio format */
    204    SDL_AudioFormat dst_format; /**< Target audio format */
    205    double rate_incr;           /**< Rate conversion increment */
    206    Uint8 *buf;                 /**< Buffer to hold entire audio data */
    207    int len;                    /**< Length of original audio buffer */
    208    int len_cvt;                /**< Length of converted audio buffer */
    209    int len_mult;               /**< buffer must be len*len_mult big */
    210    double len_ratio;           /**< Given len, final size is len*len_ratio */
    211    SDL_AudioFilter filters[10];        /**< Filter list */
    212    int filter_index;           /**< Current audio conversion function */
    213} SDL_AUDIOCVT_PACKED SDL_AudioCVT;
    214
    215
    216/* Function prototypes */
    217
    218/**
    219 *  \name Driver discovery functions
    220 *
    221 *  These functions return the list of built in audio drivers, in the
    222 *  order that they are normally initialized by default.
    223 */
    224/* @{ */
    225extern DECLSPEC int SDLCALL SDL_GetNumAudioDrivers(void);
    226extern DECLSPEC const char *SDLCALL SDL_GetAudioDriver(int index);
    227/* @} */
    228
    229/**
    230 *  \name Initialization and cleanup
    231 *
    232 *  \internal These functions are used internally, and should not be used unless
    233 *            you have a specific need to specify the audio driver you want to
    234 *            use.  You should normally use SDL_Init() or SDL_InitSubSystem().
    235 */
    236/* @{ */
    237extern DECLSPEC int SDLCALL SDL_AudioInit(const char *driver_name);
    238extern DECLSPEC void SDLCALL SDL_AudioQuit(void);
    239/* @} */
    240
    241/**
    242 *  This function returns the name of the current audio driver, or NULL
    243 *  if no driver has been initialized.
    244 */
    245extern DECLSPEC const char *SDLCALL SDL_GetCurrentAudioDriver(void);
    246
    247/**
    248 *  This function opens the audio device with the desired parameters, and
    249 *  returns 0 if successful, placing the actual hardware parameters in the
    250 *  structure pointed to by \c obtained.  If \c obtained is NULL, the audio
    251 *  data passed to the callback function will be guaranteed to be in the
    252 *  requested format, and will be automatically converted to the hardware
    253 *  audio format if necessary.  This function returns -1 if it failed
    254 *  to open the audio device, or couldn't set up the audio thread.
    255 *
    256 *  When filling in the desired audio spec structure,
    257 *    - \c desired->freq should be the desired audio frequency in samples-per-
    258 *      second.
    259 *    - \c desired->format should be the desired audio format.
    260 *    - \c desired->samples is the desired size of the audio buffer, in
    261 *      samples.  This number should be a power of two, and may be adjusted by
    262 *      the audio driver to a value more suitable for the hardware.  Good values
    263 *      seem to range between 512 and 8096 inclusive, depending on the
    264 *      application and CPU speed.  Smaller values yield faster response time,
    265 *      but can lead to underflow if the application is doing heavy processing
    266 *      and cannot fill the audio buffer in time.  A stereo sample consists of
    267 *      both right and left channels in LR ordering.
    268 *      Note that the number of samples is directly related to time by the
    269 *      following formula:  \code ms = (samples*1000)/freq \endcode
    270 *    - \c desired->size is the size in bytes of the audio buffer, and is
    271 *      calculated by SDL_OpenAudio().
    272 *    - \c desired->silence is the value used to set the buffer to silence,
    273 *      and is calculated by SDL_OpenAudio().
    274 *    - \c desired->callback should be set to a function that will be called
    275 *      when the audio device is ready for more data.  It is passed a pointer
    276 *      to the audio buffer, and the length in bytes of the audio buffer.
    277 *      This function usually runs in a separate thread, and so you should
    278 *      protect data structures that it accesses by calling SDL_LockAudio()
    279 *      and SDL_UnlockAudio() in your code. Alternately, you may pass a NULL
    280 *      pointer here, and call SDL_QueueAudio() with some frequency, to queue
    281 *      more audio samples to be played.
    282 *    - \c desired->userdata is passed as the first parameter to your callback
    283 *      function. If you passed a NULL callback, this value is ignored.
    284 *
    285 *  The audio device starts out playing silence when it's opened, and should
    286 *  be enabled for playing by calling \c SDL_PauseAudio(0) when you are ready
    287 *  for your audio callback function to be called.  Since the audio driver
    288 *  may modify the requested size of the audio buffer, you should allocate
    289 *  any local mixing buffers after you open the audio device.
    290 */
    291extern DECLSPEC int SDLCALL SDL_OpenAudio(SDL_AudioSpec * desired,
    292                                          SDL_AudioSpec * obtained);
    293
    294/**
    295 *  SDL Audio Device IDs.
    296 *
    297 *  A successful call to SDL_OpenAudio() is always device id 1, and legacy
    298 *  SDL audio APIs assume you want this device ID. SDL_OpenAudioDevice() calls
    299 *  always returns devices >= 2 on success. The legacy calls are good both
    300 *  for backwards compatibility and when you don't care about multiple,
    301 *  specific, or capture devices.
    302 */
    303typedef Uint32 SDL_AudioDeviceID;
    304
    305/**
    306 *  Get the number of available devices exposed by the current driver.
    307 *  Only valid after a successfully initializing the audio subsystem.
    308 *  Returns -1 if an explicit list of devices can't be determined; this is
    309 *  not an error. For example, if SDL is set up to talk to a remote audio
    310 *  server, it can't list every one available on the Internet, but it will
    311 *  still allow a specific host to be specified to SDL_OpenAudioDevice().
    312 *
    313 *  In many common cases, when this function returns a value <= 0, it can still
    314 *  successfully open the default device (NULL for first argument of
    315 *  SDL_OpenAudioDevice()).
    316 */
    317extern DECLSPEC int SDLCALL SDL_GetNumAudioDevices(int iscapture);
    318
    319/**
    320 *  Get the human-readable name of a specific audio device.
    321 *  Must be a value between 0 and (number of audio devices-1).
    322 *  Only valid after a successfully initializing the audio subsystem.
    323 *  The values returned by this function reflect the latest call to
    324 *  SDL_GetNumAudioDevices(); recall that function to redetect available
    325 *  hardware.
    326 *
    327 *  The string returned by this function is UTF-8 encoded, read-only, and
    328 *  managed internally. You are not to free it. If you need to keep the
    329 *  string for any length of time, you should make your own copy of it, as it
    330 *  will be invalid next time any of several other SDL functions is called.
    331 */
    332extern DECLSPEC const char *SDLCALL SDL_GetAudioDeviceName(int index,
    333                                                           int iscapture);
    334
    335
    336/**
    337 *  Open a specific audio device. Passing in a device name of NULL requests
    338 *  the most reasonable default (and is equivalent to calling SDL_OpenAudio()).
    339 *
    340 *  The device name is a UTF-8 string reported by SDL_GetAudioDeviceName(), but
    341 *  some drivers allow arbitrary and driver-specific strings, such as a
    342 *  hostname/IP address for a remote audio server, or a filename in the
    343 *  diskaudio driver.
    344 *
    345 *  \return 0 on error, a valid device ID that is >= 2 on success.
    346 *
    347 *  SDL_OpenAudio(), unlike this function, always acts on device ID 1.
    348 */
    349extern DECLSPEC SDL_AudioDeviceID SDLCALL SDL_OpenAudioDevice(const char
    350                                                              *device,
    351                                                              int iscapture,
    352                                                              const
    353                                                              SDL_AudioSpec *
    354                                                              desired,
    355                                                              SDL_AudioSpec *
    356                                                              obtained,
    357                                                              int
    358                                                              allowed_changes);
    359
    360
    361
    362/**
    363 *  \name Audio state
    364 *
    365 *  Get the current audio state.
    366 */
    367/* @{ */
    368typedef enum
    369{
    370    SDL_AUDIO_STOPPED = 0,
    371    SDL_AUDIO_PLAYING,
    372    SDL_AUDIO_PAUSED
    373} SDL_AudioStatus;
    374extern DECLSPEC SDL_AudioStatus SDLCALL SDL_GetAudioStatus(void);
    375
    376extern DECLSPEC SDL_AudioStatus SDLCALL
    377SDL_GetAudioDeviceStatus(SDL_AudioDeviceID dev);
    378/* @} *//* Audio State */
    379
    380/**
    381 *  \name Pause audio functions
    382 *
    383 *  These functions pause and unpause the audio callback processing.
    384 *  They should be called with a parameter of 0 after opening the audio
    385 *  device to start playing sound.  This is so you can safely initialize
    386 *  data for your callback function after opening the audio device.
    387 *  Silence will be written to the audio device during the pause.
    388 */
    389/* @{ */
    390extern DECLSPEC void SDLCALL SDL_PauseAudio(int pause_on);
    391extern DECLSPEC void SDLCALL SDL_PauseAudioDevice(SDL_AudioDeviceID dev,
    392                                                  int pause_on);
    393/* @} *//* Pause audio functions */
    394
    395/**
    396 *  This function loads a WAVE from the data source, automatically freeing
    397 *  that source if \c freesrc is non-zero.  For example, to load a WAVE file,
    398 *  you could do:
    399 *  \code
    400 *      SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
    401 *  \endcode
    402 *
    403 *  If this function succeeds, it returns the given SDL_AudioSpec,
    404 *  filled with the audio data format of the wave data, and sets
    405 *  \c *audio_buf to a malloc()'d buffer containing the audio data,
    406 *  and sets \c *audio_len to the length of that audio buffer, in bytes.
    407 *  You need to free the audio buffer with SDL_FreeWAV() when you are
    408 *  done with it.
    409 *
    410 *  This function returns NULL and sets the SDL error message if the
    411 *  wave file cannot be opened, uses an unknown data format, or is
    412 *  corrupt.  Currently raw and MS-ADPCM WAVE files are supported.
    413 */
    414extern DECLSPEC SDL_AudioSpec *SDLCALL SDL_LoadWAV_RW(SDL_RWops * src,
    415                                                      int freesrc,
    416                                                      SDL_AudioSpec * spec,
    417                                                      Uint8 ** audio_buf,
    418                                                      Uint32 * audio_len);
    419
    420/**
    421 *  Loads a WAV from a file.
    422 *  Compatibility convenience function.
    423 */
    424#define SDL_LoadWAV(file, spec, audio_buf, audio_len) \
    425    SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
    426
    427/**
    428 *  This function frees data previously allocated with SDL_LoadWAV_RW()
    429 */
    430extern DECLSPEC void SDLCALL SDL_FreeWAV(Uint8 * audio_buf);
    431
    432/**
    433 *  This function takes a source format and rate and a destination format
    434 *  and rate, and initializes the \c cvt structure with information needed
    435 *  by SDL_ConvertAudio() to convert a buffer of audio data from one format
    436 *  to the other.
    437 *
    438 *  \return -1 if the format conversion is not supported, 0 if there's
    439 *  no conversion needed, or 1 if the audio filter is set up.
    440 */
    441extern DECLSPEC int SDLCALL SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
    442                                              SDL_AudioFormat src_format,
    443                                              Uint8 src_channels,
    444                                              int src_rate,
    445                                              SDL_AudioFormat dst_format,
    446                                              Uint8 dst_channels,
    447                                              int dst_rate);
    448
    449/**
    450 *  Once you have initialized the \c cvt structure using SDL_BuildAudioCVT(),
    451 *  created an audio buffer \c cvt->buf, and filled it with \c cvt->len bytes of
    452 *  audio data in the source format, this function will convert it in-place
    453 *  to the desired format.
    454 *
    455 *  The data conversion may expand the size of the audio data, so the buffer
    456 *  \c cvt->buf should be allocated after the \c cvt structure is initialized by
    457 *  SDL_BuildAudioCVT(), and should be \c cvt->len*cvt->len_mult bytes long.
    458 */
    459extern DECLSPEC int SDLCALL SDL_ConvertAudio(SDL_AudioCVT * cvt);
    460
    461#define SDL_MIX_MAXVOLUME 128
    462/**
    463 *  This takes two audio buffers of the playing audio format and mixes
    464 *  them, performing addition, volume adjustment, and overflow clipping.
    465 *  The volume ranges from 0 - 128, and should be set to ::SDL_MIX_MAXVOLUME
    466 *  for full audio volume.  Note this does not change hardware volume.
    467 *  This is provided for convenience -- you can mix your own audio data.
    468 */
    469extern DECLSPEC void SDLCALL SDL_MixAudio(Uint8 * dst, const Uint8 * src,
    470                                          Uint32 len, int volume);
    471
    472/**
    473 *  This works like SDL_MixAudio(), but you specify the audio format instead of
    474 *  using the format of audio device 1. Thus it can be used when no audio
    475 *  device is open at all.
    476 */
    477extern DECLSPEC void SDLCALL SDL_MixAudioFormat(Uint8 * dst,
    478                                                const Uint8 * src,
    479                                                SDL_AudioFormat format,
    480                                                Uint32 len, int volume);
    481
    482/**
    483 *  Queue more audio on non-callback devices.
    484 *
    485 *  SDL offers two ways to feed audio to the device: you can either supply a
    486 *  callback that SDL triggers with some frequency to obtain more audio
    487 *  (pull method), or you can supply no callback, and then SDL will expect
    488 *  you to supply data at regular intervals (push method) with this function.
    489 *
    490 *  There are no limits on the amount of data you can queue, short of
    491 *  exhaustion of address space. Queued data will drain to the device as
    492 *  necessary without further intervention from you. If the device needs
    493 *  audio but there is not enough queued, it will play silence to make up
    494 *  the difference. This means you will have skips in your audio playback
    495 *  if you aren't routinely queueing sufficient data.
    496 *
    497 *  This function copies the supplied data, so you are safe to free it when
    498 *  the function returns. This function is thread-safe, but queueing to the
    499 *  same device from two threads at once does not promise which buffer will
    500 *  be queued first.
    501 *
    502 *  You may not queue audio on a device that is using an application-supplied
    503 *  callback; doing so returns an error. You have to use the audio callback
    504 *  or queue audio with this function, but not both.
    505 *
    506 *  You should not call SDL_LockAudio() on the device before queueing; SDL
    507 *  handles locking internally for this function.
    508 *
    509 *  \param dev The device ID to which we will queue audio.
    510 *  \param data The data to queue to the device for later playback.
    511 *  \param len The number of bytes (not samples!) to which (data) points.
    512 *  \return zero on success, -1 on error.
    513 *
    514 *  \sa SDL_GetQueuedAudioSize
    515 *  \sa SDL_ClearQueuedAudio
    516 */
    517extern DECLSPEC int SDLCALL SDL_QueueAudio(SDL_AudioDeviceID dev, const void *data, Uint32 len);
    518
    519/**
    520 *  Get the number of bytes of still-queued audio.
    521 *
    522 *  This is the number of bytes that have been queued for playback with
    523 *  SDL_QueueAudio(), but have not yet been sent to the hardware.
    524 *
    525 *  Once we've sent it to the hardware, this function can not decide the exact
    526 *  byte boundary of what has been played. It's possible that we just gave the
    527 *  hardware several kilobytes right before you called this function, but it
    528 *  hasn't played any of it yet, or maybe half of it, etc.
    529 *
    530 *  You may not queue audio on a device that is using an application-supplied
    531 *  callback; calling this function on such a device always returns 0.
    532 *  You have to use the audio callback or queue audio with SDL_QueueAudio(),
    533 *  but not both.
    534 *
    535 *  You should not call SDL_LockAudio() on the device before querying; SDL
    536 *  handles locking internally for this function.
    537 *
    538 *  \param dev The device ID of which we will query queued audio size.
    539 *  \return Number of bytes (not samples!) of queued audio.
    540 *
    541 *  \sa SDL_QueueAudio
    542 *  \sa SDL_ClearQueuedAudio
    543 */
    544extern DECLSPEC Uint32 SDLCALL SDL_GetQueuedAudioSize(SDL_AudioDeviceID dev);
    545
    546/**
    547 *  Drop any queued audio data waiting to be sent to the hardware.
    548 *
    549 *  Immediately after this call, SDL_GetQueuedAudioSize() will return 0 and
    550 *  the hardware will start playing silence if more audio isn't queued.
    551 *
    552 *  This will not prevent playback of queued audio that's already been sent
    553 *  to the hardware, as we can not undo that, so expect there to be some
    554 *  fraction of a second of audio that might still be heard. This can be
    555 *  useful if you want to, say, drop any pending music during a level change
    556 *  in your game.
    557 *
    558 *  You may not queue audio on a device that is using an application-supplied
    559 *  callback; calling this function on such a device is always a no-op.
    560 *  You have to use the audio callback or queue audio with SDL_QueueAudio(),
    561 *  but not both.
    562 *
    563 *  You should not call SDL_LockAudio() on the device before clearing the
    564 *  queue; SDL handles locking internally for this function.
    565 *
    566 *  This function always succeeds and thus returns void.
    567 *
    568 *  \param dev The device ID of which to clear the audio queue.
    569 *
    570 *  \sa SDL_QueueAudio
    571 *  \sa SDL_GetQueuedAudioSize
    572 */
    573extern DECLSPEC void SDLCALL SDL_ClearQueuedAudio(SDL_AudioDeviceID dev);
    574
    575
    576/**
    577 *  \name Audio lock functions
    578 *
    579 *  The lock manipulated by these functions protects the callback function.
    580 *  During a SDL_LockAudio()/SDL_UnlockAudio() pair, you can be guaranteed that
    581 *  the callback function is not running.  Do not call these from the callback
    582 *  function or you will cause deadlock.
    583 */
    584/* @{ */
    585extern DECLSPEC void SDLCALL SDL_LockAudio(void);
    586extern DECLSPEC void SDLCALL SDL_LockAudioDevice(SDL_AudioDeviceID dev);
    587extern DECLSPEC void SDLCALL SDL_UnlockAudio(void);
    588extern DECLSPEC void SDLCALL SDL_UnlockAudioDevice(SDL_AudioDeviceID dev);
    589/* @} *//* Audio lock functions */
    590
    591/**
    592 *  This function shuts down audio processing and closes the audio device.
    593 */
    594extern DECLSPEC void SDLCALL SDL_CloseAudio(void);
    595extern DECLSPEC void SDLCALL SDL_CloseAudioDevice(SDL_AudioDeviceID dev);
    596
    597/* Ends C function definitions when using C++ */
    598#ifdef __cplusplus
    599}
    600#endif
    601#include "close_code.h"
    602
    603#endif /* _SDL_audio_h */
    604
    605/* vi: set ts=4 sw=4 expandtab: */