SDL_mixer.h
author Sam Lantinga <slouken@libsdl.org>
Wed, 07 Nov 2018 07:47:50 -0800
changeset 924 9be60a9582a6
parent 915 2e274cefe1db
child 926 d6c9518fb5ee
permissions -rw-r--r--
The Debian maintainers aren't using these rules, so enable dynamic loading of shared libraries by default for the Steam Linux Runtime
     1 /*
     2   SDL_mixer:  An audio mixer library based on the SDL library
     3   Copyright (C) 1997-2018 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 #ifndef SDL_MIXER_H_
    23 #define SDL_MIXER_H_
    24 
    25 #include "SDL_stdinc.h"
    26 #include "SDL_rwops.h"
    27 #include "SDL_audio.h"
    28 #include "SDL_endian.h"
    29 #include "SDL_version.h"
    30 #include "begin_code.h"
    31 
    32 /* Set up for C function definitions, even when using C++ */
    33 #ifdef __cplusplus
    34 extern "C" {
    35 #endif
    36 
    37 /* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL
    38 */
    39 #define SDL_MIXER_MAJOR_VERSION 2
    40 #define SDL_MIXER_MINOR_VERSION 0
    41 #define SDL_MIXER_PATCHLEVEL    4
    42 
    43 /* This macro can be used to fill a version structure with the compile-time
    44  * version of the SDL_mixer library.
    45  */
    46 #define SDL_MIXER_VERSION(X)                        \
    47 {                                                   \
    48     (X)->major = SDL_MIXER_MAJOR_VERSION;           \
    49     (X)->minor = SDL_MIXER_MINOR_VERSION;           \
    50     (X)->patch = SDL_MIXER_PATCHLEVEL;              \
    51 }
    52 
    53 /* Backwards compatibility */
    54 #define MIX_MAJOR_VERSION   SDL_MIXER_MAJOR_VERSION
    55 #define MIX_MINOR_VERSION   SDL_MIXER_MINOR_VERSION
    56 #define MIX_PATCHLEVEL      SDL_MIXER_PATCHLEVEL
    57 #define MIX_VERSION(X)      SDL_MIXER_VERSION(X)
    58 
    59 /**
    60  *  This is the version number macro for the current SDL_mixer version.
    61  */
    62 #define SDL_MIXER_COMPILEDVERSION \
    63     SDL_VERSIONNUM(SDL_MIXER_MAJOR_VERSION, SDL_MIXER_MINOR_VERSION, SDL_MIXER_PATCHLEVEL)
    64 
    65 /**
    66  *  This macro will evaluate to true if compiled with SDL_mixer at least X.Y.Z.
    67  */
    68 #define SDL_MIXER_VERSION_ATLEAST(X, Y, Z) \
    69     (SDL_MIXER_COMPILEDVERSION >= SDL_VERSIONNUM(X, Y, Z))
    70 
    71 /* This function gets the version of the dynamically linked SDL_mixer library.
    72    it should NOT be used to fill a version structure, instead you should
    73    use the SDL_MIXER_VERSION() macro.
    74  */
    75 extern DECLSPEC const SDL_version * SDLCALL Mix_Linked_Version(void);
    76 
    77 typedef enum
    78 {
    79     MIX_INIT_FLAC   = 0x00000001,
    80     MIX_INIT_MOD    = 0x00000002,
    81     MIX_INIT_MP3    = 0x00000008,
    82     MIX_INIT_OGG    = 0x00000010,
    83     MIX_INIT_MID    = 0x00000020,
    84     MIX_INIT_OPUS   = 0x00000040
    85 } MIX_InitFlags;
    86 
    87 /* Loads dynamic libraries and prepares them for use.  Flags should be
    88    one or more flags from MIX_InitFlags OR'd together.
    89    It returns the flags successfully initialized, or 0 on failure.
    90  */
    91 extern DECLSPEC int SDLCALL Mix_Init(int flags);
    92 
    93 /* Unloads libraries loaded with Mix_Init */
    94 extern DECLSPEC void SDLCALL Mix_Quit(void);
    95 
    96 
    97 /* The default mixer has 8 simultaneous mixing channels */
    98 #ifndef MIX_CHANNELS
    99 #define MIX_CHANNELS    8
   100 #endif
   101 
   102 /* Good default values for a PC soundcard */
   103 #define MIX_DEFAULT_FREQUENCY   22050
   104 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   105 #define MIX_DEFAULT_FORMAT  AUDIO_S16LSB
   106 #else
   107 #define MIX_DEFAULT_FORMAT  AUDIO_S16MSB
   108 #endif
   109 #define MIX_DEFAULT_CHANNELS    2
   110 #define MIX_MAX_VOLUME          SDL_MIX_MAXVOLUME /* Volume of a chunk */
   111 
   112 /* The internal format for an audio chunk */
   113 typedef struct Mix_Chunk {
   114     int allocated;
   115     Uint8 *abuf;
   116     Uint32 alen;
   117     Uint8 volume;       /* Per-sample volume, 0-128 */
   118 } Mix_Chunk;
   119 
   120 /* The different fading types supported */
   121 typedef enum {
   122     MIX_NO_FADING,
   123     MIX_FADING_OUT,
   124     MIX_FADING_IN
   125 } Mix_Fading;
   126 
   127 /* These are types of music files (not libraries used to load them) */
   128 typedef enum {
   129     MUS_NONE,
   130     MUS_CMD,
   131     MUS_WAV,
   132     MUS_MOD,
   133     MUS_MID,
   134     MUS_OGG,
   135     MUS_MP3,
   136     MUS_MP3_MAD_UNUSED,
   137     MUS_FLAC,
   138     MUS_MODPLUG_UNUSED,
   139     MUS_OPUS
   140 } Mix_MusicType;
   141 
   142 /* The internal format for a music chunk interpreted via mikmod */
   143 typedef struct _Mix_Music Mix_Music;
   144 
   145 /* Open the mixer with a certain audio format */
   146 extern DECLSPEC int SDLCALL Mix_OpenAudio(int frequency, Uint16 format, int channels, int chunksize);
   147 
   148 /* Open the mixer with specific device and certain audio format */
   149 extern DECLSPEC int SDLCALL Mix_OpenAudioDevice(int frequency, Uint16 format, int channels, int chunksize, const char* device, int allowed_changes);
   150 
   151 /* Dynamically change the number of channels managed by the mixer.
   152    If decreasing the number of channels, the upper channels are
   153    stopped.
   154    This function returns the new number of allocated channels.
   155  */
   156 extern DECLSPEC int SDLCALL Mix_AllocateChannels(int numchans);
   157 
   158 /* Find out what the actual audio device parameters are.
   159    This function returns 1 if the audio has been opened, 0 otherwise.
   160  */
   161 extern DECLSPEC int SDLCALL Mix_QuerySpec(int *frequency,Uint16 *format,int *channels);
   162 
   163 /* Load a wave file or a music (.mod .s3m .it .xm) file */
   164 extern DECLSPEC Mix_Chunk * SDLCALL Mix_LoadWAV_RW(SDL_RWops *src, int freesrc);
   165 #define Mix_LoadWAV(file)   Mix_LoadWAV_RW(SDL_RWFromFile(file, "rb"), 1)
   166 extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS(const char *file);
   167 
   168 /* Load a music file from an SDL_RWop object (Ogg and MikMod specific currently)
   169    Matt Campbell (matt@campbellhome.dhs.org) April 2000 */
   170 extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS_RW(SDL_RWops *src, int freesrc);
   171 
   172 /* Load a music file from an SDL_RWop object assuming a specific format */
   173 extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUSType_RW(SDL_RWops *src, Mix_MusicType type, int freesrc);
   174 
   175 /* Load a wave file of the mixer format from a memory buffer */
   176 extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_WAV(Uint8 *mem);
   177 
   178 /* Load raw audio data of the mixer format from a memory buffer */
   179 extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_RAW(Uint8 *mem, Uint32 len);
   180 
   181 /* Free an audio chunk previously loaded */
   182 extern DECLSPEC void SDLCALL Mix_FreeChunk(Mix_Chunk *chunk);
   183 extern DECLSPEC void SDLCALL Mix_FreeMusic(Mix_Music *music);
   184 
   185 /* Get a list of chunk/music decoders that this build of SDL_mixer provides.
   186    This list can change between builds AND runs of the program, if external
   187    libraries that add functionality become available.
   188    You must successfully call Mix_OpenAudio() before calling these functions.
   189    This API is only available in SDL_mixer 1.2.9 and later.
   190 
   191    // usage...
   192    int i;
   193    const int total = Mix_GetNumChunkDecoders();
   194    for (i = 0; i < total; i++)
   195        printf("Supported chunk decoder: [%s]\n", Mix_GetChunkDecoder(i));
   196 
   197    Appearing in this list doesn't promise your specific audio file will
   198    decode...but it's handy to know if you have, say, a functioning Timidity
   199    install.
   200 
   201    These return values are static, read-only data; do not modify or free it.
   202    The pointers remain valid until you call Mix_CloseAudio().
   203 */
   204 extern DECLSPEC int SDLCALL Mix_GetNumChunkDecoders(void);
   205 extern DECLSPEC const char * SDLCALL Mix_GetChunkDecoder(int index);
   206 extern DECLSPEC SDL_bool SDLCALL Mix_HasChunkDecoder(const char *name);
   207 extern DECLSPEC int SDLCALL Mix_GetNumMusicDecoders(void);
   208 extern DECLSPEC const char * SDLCALL Mix_GetMusicDecoder(int index);
   209 extern DECLSPEC SDL_bool SDLCALL Mix_HasMusicDecoder(const char *name);
   210 
   211 /* Find out the music format of a mixer music, or the currently playing
   212    music, if 'music' is NULL.
   213 */
   214 extern DECLSPEC Mix_MusicType SDLCALL Mix_GetMusicType(const Mix_Music *music);
   215 
   216 /* Set a function that is called after all mixing is performed.
   217    This can be used to provide real-time visual display of the audio stream
   218    or add a custom mixer filter for the stream data.
   219 */
   220 extern DECLSPEC void SDLCALL Mix_SetPostMix(void (SDLCALL *mix_func)(void *udata, Uint8 *stream, int len), void *arg);
   221 
   222 /* Add your own music player or additional mixer function.
   223    If 'mix_func' is NULL, the default music player is re-enabled.
   224  */
   225 extern DECLSPEC void SDLCALL Mix_HookMusic(void (SDLCALL *mix_func)(void *udata, Uint8 *stream, int len), void *arg);
   226 
   227 /* Add your own callback for when the music has finished playing or when it is
   228  * stopped from a call to Mix_HaltMusic.
   229  */
   230 extern DECLSPEC void SDLCALL Mix_HookMusicFinished(void (SDLCALL *music_finished)(void));
   231 
   232 /* Get a pointer to the user data for the current music hook */
   233 extern DECLSPEC void * SDLCALL Mix_GetMusicHookData(void);
   234 
   235 /*
   236  * Add your own callback when a channel has finished playing. NULL
   237  *  to disable callback. The callback may be called from the mixer's audio
   238  *  callback or it could be called as a result of Mix_HaltChannel(), etc.
   239  *  do not call SDL_LockAudio() from this callback; you will either be
   240  *  inside the audio callback, or SDL_mixer will explicitly lock the audio
   241  *  before calling your callback.
   242  */
   243 extern DECLSPEC void SDLCALL Mix_ChannelFinished(void (SDLCALL *channel_finished)(int channel));
   244 
   245 
   246 /* Special Effects API by ryan c. gordon. (icculus@icculus.org) */
   247 
   248 #define MIX_CHANNEL_POST  -2
   249 
   250 /* This is the format of a special effect callback:
   251  *
   252  *   myeffect(int chan, void *stream, int len, void *udata);
   253  *
   254  * (chan) is the channel number that your effect is affecting. (stream) is
   255  *  the buffer of data to work upon. (len) is the size of (stream), and
   256  *  (udata) is a user-defined bit of data, which you pass as the last arg of
   257  *  Mix_RegisterEffect(), and is passed back unmolested to your callback.
   258  *  Your effect changes the contents of (stream) based on whatever parameters
   259  *  are significant, or just leaves it be, if you prefer. You can do whatever
   260  *  you like to the buffer, though, and it will continue in its changed state
   261  *  down the mixing pipeline, through any other effect functions, then finally
   262  *  to be mixed with the rest of the channels and music for the final output
   263  *  stream.
   264  *
   265  * DO NOT EVER call SDL_LockAudio() from your callback function!
   266  */
   267 typedef void (SDLCALL *Mix_EffectFunc_t)(int chan, void *stream, int len, void *udata);
   268 
   269 /*
   270  * This is a callback that signifies that a channel has finished all its
   271  *  loops and has completed playback. This gets called if the buffer
   272  *  plays out normally, or if you call Mix_HaltChannel(), implicitly stop
   273  *  a channel via Mix_AllocateChannels(), or unregister a callback while
   274  *  it's still playing.
   275  *
   276  * DO NOT EVER call SDL_LockAudio() from your callback function!
   277  */
   278 typedef void (SDLCALL *Mix_EffectDone_t)(int chan, void *udata);
   279 
   280 
   281 /* Register a special effect function. At mixing time, the channel data is
   282  *  copied into a buffer and passed through each registered effect function.
   283  *  After it passes through all the functions, it is mixed into the final
   284  *  output stream. The copy to buffer is performed once, then each effect
   285  *  function performs on the output of the previous effect. Understand that
   286  *  this extra copy to a buffer is not performed if there are no effects
   287  *  registered for a given chunk, which saves CPU cycles, and any given
   288  *  effect will be extra cycles, too, so it is crucial that your code run
   289  *  fast. Also note that the data that your function is given is in the
   290  *  format of the sound device, and not the format you gave to Mix_OpenAudio(),
   291  *  although they may in reality be the same. This is an unfortunate but
   292  *  necessary speed concern. Use Mix_QuerySpec() to determine if you can
   293  *  handle the data before you register your effect, and take appropriate
   294  *  actions.
   295  * You may also specify a callback (Mix_EffectDone_t) that is called when
   296  *  the channel finishes playing. This gives you a more fine-grained control
   297  *  than Mix_ChannelFinished(), in case you need to free effect-specific
   298  *  resources, etc. If you don't need this, you can specify NULL.
   299  * You may set the callbacks before or after calling Mix_PlayChannel().
   300  * Things like Mix_SetPanning() are just internal special effect functions,
   301  *  so if you are using that, you've already incurred the overhead of a copy
   302  *  to a separate buffer, and that these effects will be in the queue with
   303  *  any functions you've registered. The list of registered effects for a
   304  *  channel is reset when a chunk finishes playing, so you need to explicitly
   305  *  set them with each call to Mix_PlayChannel*().
   306  * You may also register a special effect function that is to be run after
   307  *  final mixing occurs. The rules for these callbacks are identical to those
   308  *  in Mix_RegisterEffect, but they are run after all the channels and the
   309  *  music have been mixed into a single stream, whereas channel-specific
   310  *  effects run on a given channel before any other mixing occurs. These
   311  *  global effect callbacks are call "posteffects". Posteffects only have
   312  *  their Mix_EffectDone_t function called when they are unregistered (since
   313  *  the main output stream is never "done" in the same sense as a channel).
   314  *  You must unregister them manually when you've had enough. Your callback
   315  *  will be told that the channel being mixed is (MIX_CHANNEL_POST) if the
   316  *  processing is considered a posteffect.
   317  *
   318  * After all these effects have finished processing, the callback registered
   319  *  through Mix_SetPostMix() runs, and then the stream goes to the audio
   320  *  device.
   321  *
   322  * DO NOT EVER call SDL_LockAudio() from your callback function!
   323  *
   324  * returns zero if error (no such channel), nonzero if added.
   325  *  Error messages can be retrieved from Mix_GetError().
   326  */
   327 extern DECLSPEC int SDLCALL Mix_RegisterEffect(int chan, Mix_EffectFunc_t f, Mix_EffectDone_t d, void *arg);
   328 
   329 
   330 /* You may not need to call this explicitly, unless you need to stop an
   331  *  effect from processing in the middle of a chunk's playback.
   332  * Posteffects are never implicitly unregistered as they are for channels,
   333  *  but they may be explicitly unregistered through this function by
   334  *  specifying MIX_CHANNEL_POST for a channel.
   335  * returns zero if error (no such channel or effect), nonzero if removed.
   336  *  Error messages can be retrieved from Mix_GetError().
   337  */
   338 extern DECLSPEC int SDLCALL Mix_UnregisterEffect(int channel, Mix_EffectFunc_t f);
   339 
   340 
   341 /* You may not need to call this explicitly, unless you need to stop all
   342  *  effects from processing in the middle of a chunk's playback. Note that
   343  *  this will also shut off some internal effect processing, since
   344  *  Mix_SetPanning() and others may use this API under the hood. This is
   345  *  called internally when a channel completes playback.
   346  * Posteffects are never implicitly unregistered as they are for channels,
   347  *  but they may be explicitly unregistered through this function by
   348  *  specifying MIX_CHANNEL_POST for a channel.
   349  * returns zero if error (no such channel), nonzero if all effects removed.
   350  *  Error messages can be retrieved from Mix_GetError().
   351  */
   352 extern DECLSPEC int SDLCALL Mix_UnregisterAllEffects(int channel);
   353 
   354 
   355 #define MIX_EFFECTSMAXSPEED  "MIX_EFFECTSMAXSPEED"
   356 
   357 /*
   358  * These are the internally-defined mixing effects. They use the same API that
   359  *  effects defined in the application use, but are provided here as a
   360  *  convenience. Some effects can reduce their quality or use more memory in
   361  *  the name of speed; to enable this, make sure the environment variable
   362  *  MIX_EFFECTSMAXSPEED (see above) is defined before you call
   363  *  Mix_OpenAudio().
   364  */
   365 
   366 
   367 /* Set the panning of a channel. The left and right channels are specified
   368  *  as integers between 0 and 255, quietest to loudest, respectively.
   369  *
   370  * Technically, this is just individual volume control for a sample with
   371  *  two (stereo) channels, so it can be used for more than just panning.
   372  *  If you want real panning, call it like this:
   373  *
   374  *   Mix_SetPanning(channel, left, 255 - left);
   375  *
   376  * ...which isn't so hard.
   377  *
   378  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   379  *  the panning will be done to the final mixed stream before passing it on
   380  *  to the audio device.
   381  *
   382  * This uses the Mix_RegisterEffect() API internally, and returns without
   383  *  registering the effect function if the audio device is not configured
   384  *  for stereo output. Setting both (left) and (right) to 255 causes this
   385  *  effect to be unregistered, since that is the data's normal state.
   386  *
   387  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   388  *  nonzero if panning effect enabled. Note that an audio device in mono
   389  *  mode is a no-op, but this call will return successful in that case.
   390  *  Error messages can be retrieved from Mix_GetError().
   391  */
   392 extern DECLSPEC int SDLCALL Mix_SetPanning(int channel, Uint8 left, Uint8 right);
   393 
   394 
   395 /* Set the position of a channel. (angle) is an integer from 0 to 360, that
   396  *  specifies the location of the sound in relation to the listener. (angle)
   397  *  will be reduced as neccesary (540 becomes 180 degrees, -100 becomes 260).
   398  *  Angle 0 is due north, and rotates clockwise as the value increases.
   399  *  For efficiency, the precision of this effect may be limited (angles 1
   400  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
   401  *  (distance) is an integer between 0 and 255 that specifies the space
   402  *  between the sound and the listener. The larger the number, the further
   403  *  away the sound is. Using 255 does not guarantee that the channel will be
   404  *  culled from the mixing process or be completely silent. For efficiency,
   405  *  the precision of this effect may be limited (distance 0 through 5 might
   406  *  all produce the same effect, 6 through 10 are equal, etc). Setting (angle)
   407  *  and (distance) to 0 unregisters this effect, since the data would be
   408  *  unchanged.
   409  *
   410  * If you need more precise positional audio, consider using OpenAL for
   411  *  spatialized effects instead of SDL_mixer. This is only meant to be a
   412  *  basic effect for simple "3D" games.
   413  *
   414  * If the audio device is configured for mono output, then you won't get
   415  *  any effectiveness from the angle; however, distance attenuation on the
   416  *  channel will still occur. While this effect will function with stereo
   417  *  voices, it makes more sense to use voices with only one channel of sound,
   418  *  so when they are mixed through this effect, the positioning will sound
   419  *  correct. You can convert them to mono through SDL before giving them to
   420  *  the mixer in the first place if you like.
   421  *
   422  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   423  *  the positioning will be done to the final mixed stream before passing it
   424  *  on to the audio device.
   425  *
   426  * This is a convenience wrapper over Mix_SetDistance() and Mix_SetPanning().
   427  *
   428  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   429  *  nonzero if position effect is enabled.
   430  *  Error messages can be retrieved from Mix_GetError().
   431  */
   432 extern DECLSPEC int SDLCALL Mix_SetPosition(int channel, Sint16 angle, Uint8 distance);
   433 
   434 
   435 /* Set the "distance" of a channel. (distance) is an integer from 0 to 255
   436  *  that specifies the location of the sound in relation to the listener.
   437  *  Distance 0 is overlapping the listener, and 255 is as far away as possible
   438  *  A distance of 255 does not guarantee silence; in such a case, you might
   439  *  want to try changing the chunk's volume, or just cull the sample from the
   440  *  mixing process with Mix_HaltChannel().
   441  * For efficiency, the precision of this effect may be limited (distances 1
   442  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
   443  *  (distance) is an integer between 0 and 255 that specifies the space
   444  *  between the sound and the listener. The larger the number, the further
   445  *  away the sound is.
   446  * Setting (distance) to 0 unregisters this effect, since the data would be
   447  *  unchanged.
   448  * If you need more precise positional audio, consider using OpenAL for
   449  *  spatialized effects instead of SDL_mixer. This is only meant to be a
   450  *  basic effect for simple "3D" games.
   451  *
   452  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   453  *  the distance attenuation will be done to the final mixed stream before
   454  *  passing it on to the audio device.
   455  *
   456  * This uses the Mix_RegisterEffect() API internally.
   457  *
   458  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   459  *  nonzero if position effect is enabled.
   460  *  Error messages can be retrieved from Mix_GetError().
   461  */
   462 extern DECLSPEC int SDLCALL Mix_SetDistance(int channel, Uint8 distance);
   463 
   464 
   465 /*
   466  * !!! FIXME : Haven't implemented, since the effect goes past the
   467  *              end of the sound buffer. Will have to think about this.
   468  *               --ryan.
   469  */
   470 #if 0
   471 /* Causes an echo effect to be mixed into a sound. (echo) is the amount
   472  *  of echo to mix. 0 is no echo, 255 is infinite (and probably not
   473  *  what you want).
   474  *
   475  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   476  *  the reverbing will be done to the final mixed stream before passing it on
   477  *  to the audio device.
   478  *
   479  * This uses the Mix_RegisterEffect() API internally. If you specify an echo
   480  *  of zero, the effect is unregistered, as the data is already in that state.
   481  *
   482  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   483  *  nonzero if reversing effect is enabled.
   484  *  Error messages can be retrieved from Mix_GetError().
   485  */
   486 extern no_parse_DECLSPEC int SDLCALL Mix_SetReverb(int channel, Uint8 echo);
   487 #endif
   488 
   489 /* Causes a channel to reverse its stereo. This is handy if the user has his
   490  *  speakers hooked up backwards, or you would like to have a minor bit of
   491  *  psychedelia in your sound code.  :)  Calling this function with (flip)
   492  *  set to non-zero reverses the chunks's usual channels. If (flip) is zero,
   493  *  the effect is unregistered.
   494  *
   495  * This uses the Mix_RegisterEffect() API internally, and thus is probably
   496  *  more CPU intensive than having the user just plug in his speakers
   497  *  correctly. Mix_SetReverseStereo() returns without registering the effect
   498  *  function if the audio device is not configured for stereo output.
   499  *
   500  * If you specify MIX_CHANNEL_POST for (channel), then this the effect is used
   501  *  on the final mixed stream before sending it on to the audio device (a
   502  *  posteffect).
   503  *
   504  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   505  *  nonzero if reversing effect is enabled. Note that an audio device in mono
   506  *  mode is a no-op, but this call will return successful in that case.
   507  *  Error messages can be retrieved from Mix_GetError().
   508  */
   509 extern DECLSPEC int SDLCALL Mix_SetReverseStereo(int channel, int flip);
   510 
   511 /* end of effects API. --ryan. */
   512 
   513 
   514 /* Reserve the first channels (0 -> n-1) for the application, i.e. don't allocate
   515    them dynamically to the next sample if requested with a -1 value below.
   516    Returns the number of reserved channels.
   517  */
   518 extern DECLSPEC int SDLCALL Mix_ReserveChannels(int num);
   519 
   520 /* Channel grouping functions */
   521 
   522 /* Attach a tag to a channel. A tag can be assigned to several mixer
   523    channels, to form groups of channels.
   524    If 'tag' is -1, the tag is removed (actually -1 is the tag used to
   525    represent the group of all the channels).
   526    Returns true if everything was OK.
   527  */
   528 extern DECLSPEC int SDLCALL Mix_GroupChannel(int which, int tag);
   529 /* Assign several consecutive channels to a group */
   530 extern DECLSPEC int SDLCALL Mix_GroupChannels(int from, int to, int tag);
   531 /* Finds the first available channel in a group of channels,
   532    returning -1 if none are available.
   533  */
   534 extern DECLSPEC int SDLCALL Mix_GroupAvailable(int tag);
   535 /* Returns the number of channels in a group. This is also a subtle
   536    way to get the total number of channels when 'tag' is -1
   537  */
   538 extern DECLSPEC int SDLCALL Mix_GroupCount(int tag);
   539 /* Finds the "oldest" sample playing in a group of channels */
   540 extern DECLSPEC int SDLCALL Mix_GroupOldest(int tag);
   541 /* Finds the "most recent" (i.e. last) sample playing in a group of channels */
   542 extern DECLSPEC int SDLCALL Mix_GroupNewer(int tag);
   543 
   544 /* Play an audio chunk on a specific channel.
   545    If the specified channel is -1, play on the first free channel.
   546    If 'loops' is greater than zero, loop the sound that many times.
   547    If 'loops' is -1, loop inifinitely (~65000 times).
   548    Returns which channel was used to play the sound.
   549 */
   550 #define Mix_PlayChannel(channel,chunk,loops) Mix_PlayChannelTimed(channel,chunk,loops,-1)
   551 /* The same as above, but the sound is played at most 'ticks' milliseconds */
   552 extern DECLSPEC int SDLCALL Mix_PlayChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ticks);
   553 extern DECLSPEC int SDLCALL Mix_PlayMusic(Mix_Music *music, int loops);
   554 
   555 /* Fade in music or a channel over "ms" milliseconds, same semantics as the "Play" functions */
   556 extern DECLSPEC int SDLCALL Mix_FadeInMusic(Mix_Music *music, int loops, int ms);
   557 extern DECLSPEC int SDLCALL Mix_FadeInMusicPos(Mix_Music *music, int loops, int ms, double position);
   558 #define Mix_FadeInChannel(channel,chunk,loops,ms) Mix_FadeInChannelTimed(channel,chunk,loops,ms,-1)
   559 extern DECLSPEC int SDLCALL Mix_FadeInChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ms, int ticks);
   560 
   561 /* Set the volume in the range of 0-128 of a specific channel or chunk.
   562    If the specified channel is -1, set volume for all channels.
   563    Returns the original volume.
   564    If the specified volume is -1, just return the current volume.
   565 */
   566 extern DECLSPEC int SDLCALL Mix_Volume(int channel, int volume);
   567 extern DECLSPEC int SDLCALL Mix_VolumeChunk(Mix_Chunk *chunk, int volume);
   568 extern DECLSPEC int SDLCALL Mix_VolumeMusic(int volume);
   569 
   570 /* Halt playing of a particular channel */
   571 extern DECLSPEC int SDLCALL Mix_HaltChannel(int channel);
   572 extern DECLSPEC int SDLCALL Mix_HaltGroup(int tag);
   573 extern DECLSPEC int SDLCALL Mix_HaltMusic(void);
   574 
   575 /* Change the expiration delay for a particular channel.
   576    The sample will stop playing after the 'ticks' milliseconds have elapsed,
   577    or remove the expiration if 'ticks' is -1
   578 */
   579 extern DECLSPEC int SDLCALL Mix_ExpireChannel(int channel, int ticks);
   580 
   581 /* Halt a channel, fading it out progressively till it's silent
   582    The ms parameter indicates the number of milliseconds the fading
   583    will take.
   584  */
   585 extern DECLSPEC int SDLCALL Mix_FadeOutChannel(int which, int ms);
   586 extern DECLSPEC int SDLCALL Mix_FadeOutGroup(int tag, int ms);
   587 extern DECLSPEC int SDLCALL Mix_FadeOutMusic(int ms);
   588 
   589 /* Query the fading status of a channel */
   590 extern DECLSPEC Mix_Fading SDLCALL Mix_FadingMusic(void);
   591 extern DECLSPEC Mix_Fading SDLCALL Mix_FadingChannel(int which);
   592 
   593 /* Pause/Resume a particular channel */
   594 extern DECLSPEC void SDLCALL Mix_Pause(int channel);
   595 extern DECLSPEC void SDLCALL Mix_Resume(int channel);
   596 extern DECLSPEC int SDLCALL Mix_Paused(int channel);
   597 
   598 /* Pause/Resume the music stream */
   599 extern DECLSPEC void SDLCALL Mix_PauseMusic(void);
   600 extern DECLSPEC void SDLCALL Mix_ResumeMusic(void);
   601 extern DECLSPEC void SDLCALL Mix_RewindMusic(void);
   602 extern DECLSPEC int SDLCALL Mix_PausedMusic(void);
   603 
   604 /* Set the current position in the music stream.
   605    This returns 0 if successful, or -1 if it failed or isn't implemented.
   606    This function is only implemented for MOD music formats (set pattern
   607    order number) and for OGG, FLAC, MP3_MAD, MP3_MPG and MODPLUG music
   608    (set position in seconds), at the moment.
   609 */
   610 extern DECLSPEC int SDLCALL Mix_SetMusicPosition(double position);
   611 
   612 /* Check the status of a specific channel.
   613    If the specified channel is -1, check all channels.
   614 */
   615 extern DECLSPEC int SDLCALL Mix_Playing(int channel);
   616 extern DECLSPEC int SDLCALL Mix_PlayingMusic(void);
   617 
   618 /* Stop music and set external music playback command */
   619 extern DECLSPEC int SDLCALL Mix_SetMusicCMD(const char *command);
   620 
   621 /* Synchro value is set by MikMod from modules while playing */
   622 extern DECLSPEC int SDLCALL Mix_SetSynchroValue(int value);
   623 extern DECLSPEC int SDLCALL Mix_GetSynchroValue(void);
   624 
   625 /* Set/Get/Iterate SoundFonts paths to use by supported MIDI backends */
   626 extern DECLSPEC int SDLCALL Mix_SetSoundFonts(const char *paths);
   627 extern DECLSPEC const char* SDLCALL Mix_GetSoundFonts(void);
   628 extern DECLSPEC int SDLCALL Mix_EachSoundFont(int (SDLCALL *function)(const char*, void*), void *data);
   629 
   630 /* Get the Mix_Chunk currently associated with a mixer channel
   631     Returns NULL if it's an invalid channel, or there's no chunk associated.
   632 */
   633 extern DECLSPEC Mix_Chunk * SDLCALL Mix_GetChunk(int channel);
   634 
   635 /* Close the mixer, halting all playing audio */
   636 extern DECLSPEC void SDLCALL Mix_CloseAudio(void);
   637 
   638 /* We'll use SDL for reporting errors */
   639 #define Mix_SetError    SDL_SetError
   640 #define Mix_GetError    SDL_GetError
   641 #define Mix_ClearError  SDL_ClearError
   642 
   643 /* Ends C function definitions when using C++ */
   644 #ifdef __cplusplus
   645 }
   646 #endif
   647 #include "close_code.h"
   648 
   649 #endif /* SDL_MIXER_H_ */
   650 
   651 /* vi: set ts=4 sw=4 expandtab: */