SDL_mixer.h
author Sam Lantinga <slouken@libsdl.org>
Sat, 03 May 2003 20:15:25 +0000
changeset 225 0ce0217441fc
parent 182 9e494f7db8d1
child 226 3691a375f2e6
permissions -rw-r--r--
Kyle Davenport - Sat, 19 Apr 2003 17:13:31 -0500
* Added .la files to the development RPM, fixing RPM build on RedHat 8
     1 /*
     2     SDL_mixer:  An audio mixer library based on the SDL library
     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
    20     slouken@libsdl.org
    21 */
    22 
    23 /* $Id$ */
    24 
    25 #ifndef _MIXER_H_
    26 #define _MIXER_H_
    27 
    28 #include "SDL_types.h"
    29 #include "SDL_rwops.h"
    30 #include "SDL_audio.h"
    31 #include "SDL_byteorder.h"
    32 #include "SDL_version.h"
    33 #include "begin_code.h"
    34 
    35 /* Set up for C function definitions, even when using C++ */
    36 #ifdef __cplusplus
    37 extern "C" {
    38 #endif
    39 
    40 /* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL
    41 */
    42 #define MIX_MAJOR_VERSION	1
    43 #define MIX_MINOR_VERSION	2
    44 #define MIX_PATCHLEVEL		6
    45 
    46 /* This macro can be used to fill a version structure with the compile-time
    47  * version of the SDL_mixer library.
    48  */
    49 #define MIX_VERSION(X)							\
    50 {									\
    51 	(X)->major = MIX_MAJOR_VERSION;					\
    52 	(X)->minor = MIX_MINOR_VERSION;					\
    53 	(X)->patch = MIX_PATCHLEVEL;					\
    54 }
    55 
    56 
    57 /* This function gets the version of the dynamically linked SDL_mixer library.
    58    it should NOT be used to fill a version structure, instead you should
    59    use the MIX_VERSION() macro.
    60  */
    61 extern DECLSPEC const SDL_version * SDLCALL Mix_Linked_Version(void);
    62 
    63 
    64 /* The default mixer has 8 simultaneous mixing channels */
    65 #ifndef MIX_CHANNELS
    66 #define MIX_CHANNELS	8
    67 #endif
    68 
    69 /* Good default values for a PC soundcard */
    70 #define MIX_DEFAULT_FREQUENCY	22050
    71 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
    72 #define MIX_DEFAULT_FORMAT	AUDIO_S16LSB
    73 #else
    74 #define MIX_DEFAULT_FORMAT	AUDIO_S16MSB
    75 #endif
    76 #define MIX_DEFAULT_CHANNELS	2
    77 #define MIX_MAX_VOLUME		128	/* Volume of a chunk */
    78 
    79 /* The internal format for an audio chunk */
    80 typedef struct {
    81 	int allocated;
    82 	Uint8 *abuf;
    83 	Uint32 alen;
    84 	Uint8 volume;		/* Per-sample volume, 0-128 */
    85 } Mix_Chunk;
    86 
    87 /* The different fading types supported */
    88 typedef enum {
    89 	MIX_NO_FADING,
    90 	MIX_FADING_OUT,
    91 	MIX_FADING_IN
    92 } Mix_Fading;
    93 
    94 typedef enum {
    95 	MUS_NONE,
    96 	MUS_CMD,
    97 	MUS_WAV,
    98 	MUS_MOD,
    99 	MUS_MID,
   100 	MUS_OGG,
   101 	MUS_MP3
   102 } Mix_MusicType;
   103 
   104 /* The internal format for a music chunk interpreted via mikmod */
   105 typedef struct _Mix_Music Mix_Music;
   106 
   107 /* Open the mixer with a certain audio format */
   108 extern DECLSPEC int SDLCALL Mix_OpenAudio(int frequency, Uint16 format, int channels,
   109 							int chunksize);
   110 
   111 /* Dynamically change the number of channels managed by the mixer.
   112    If decreasing the number of channels, the upper channels are
   113    stopped.
   114    This function returns the new number of allocated channels.
   115  */
   116 extern DECLSPEC int SDLCALL Mix_AllocateChannels(int numchans);
   117 
   118 /* Find out what the actual audio device parameters are.
   119    This function returns 1 if the audio has been opened, 0 otherwise.
   120  */
   121 extern DECLSPEC int SDLCALL Mix_QuerySpec(int *frequency,Uint16 *format,int *channels);
   122 
   123 /* Load a wave file or a music (.mod .s3m .it .xm) file */
   124 extern DECLSPEC Mix_Chunk * SDLCALL Mix_LoadWAV_RW(SDL_RWops *src, int freesrc);
   125 #define Mix_LoadWAV(file)	Mix_LoadWAV_RW(SDL_RWFromFile(file, "rb"), 1)
   126 extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS(const char *file);
   127 
   128 #if 0 /* This hasn't been hooked into music.c yet */
   129 /* Load a music file from an SDL_RWop object (MikMod-specific currently)
   130    Matt Campbell (matt@campbellhome.dhs.org) April 2000 */
   131 extern no_parse_DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS_RW(SDL_RWops *rw);
   132 #endif
   133 
   134 /* Load a wave file of the mixer format from a memory buffer */
   135 extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_WAV(Uint8 *mem);
   136 
   137 /* Load raw audio data of the mixer format from a memory buffer */
   138 extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_RAW(Uint8 *mem, Uint32 len);
   139 
   140 /* Free an audio chunk previously loaded */
   141 extern DECLSPEC void SDLCALL Mix_FreeChunk(Mix_Chunk *chunk);
   142 extern DECLSPEC void SDLCALL Mix_FreeMusic(Mix_Music *music);
   143 
   144 /* Find out the music format of a mixer music, or the currently playing
   145    music, if 'music' is NULL.
   146 */
   147 extern DECLSPEC Mix_MusicType SDLCALL Mix_GetMusicType(const Mix_Music *music);
   148 
   149 /* Set a function that is called after all mixing is performed.
   150    This can be used to provide real-time visual display of the audio stream
   151    or add a custom mixer filter for the stream data.
   152 */
   153 extern DECLSPEC void SDLCALL Mix_SetPostMix(void (*mix_func)
   154                              (void *udata, Uint8 *stream, int len), void *arg);
   155 
   156 /* Add your own music player or additional mixer function.
   157    If 'mix_func' is NULL, the default music player is re-enabled.
   158  */
   159 extern DECLSPEC void SDLCALL Mix_HookMusic(void (*mix_func)
   160                           (void *udata, Uint8 *stream, int len), void *arg);
   161 
   162 /* Add your own callback when the music has finished playing.
   163    This callback is only called if the music finishes naturally.
   164  */
   165 extern DECLSPEC void SDLCALL Mix_HookMusicFinished(void (*music_finished)(void));
   166 
   167 /* Get a pointer to the user data for the current music hook */
   168 extern DECLSPEC void * SDLCALL Mix_GetMusicHookData(void);
   169 
   170 /*
   171  * Add your own callback when a channel has finished playing. NULL
   172  *  to disable callback. The callback may be called from the mixer's audio 
   173  *  callback or it could be called as a result of Mix_HaltChannel(), etc.
   174  *  do not call SDL_LockAudio() from this callback; you will either be 
   175  *  inside the audio callback, or SDL_mixer will explicitly lock the audio
   176  *  before calling your callback.
   177  */
   178 extern DECLSPEC void SDLCALL Mix_ChannelFinished(void (*channel_finished)(int channel));
   179 
   180 
   181 /* Special Effects API by ryan c. gordon. (icculus@linuxgames.com) */
   182 
   183 #define MIX_CHANNEL_POST  -2
   184 
   185 /* This is the format of a special effect callback:
   186  *
   187  *   myeffect(int chan, void *stream, int len, void *udata);
   188  *
   189  * (chan) is the channel number that your effect is affecting. (stream) is
   190  *  the buffer of data to work upon. (len) is the size of (stream), and
   191  *  (udata) is a user-defined bit of data, which you pass as the last arg of
   192  *  Mix_RegisterEffect(), and is passed back unmolested to your callback.
   193  *  Your effect changes the contents of (stream) based on whatever parameters
   194  *  are significant, or just leaves it be, if you prefer. You can do whatever
   195  *  you like to the buffer, though, and it will continue in its changed state
   196  *  down the mixing pipeline, through any other effect functions, then finally
   197  *  to be mixed with the rest of the channels and music for the final output
   198  *  stream.
   199  *
   200  * DO NOT EVER call SDL_LockAudio() from your callback function!
   201  */
   202 typedef void (*Mix_EffectFunc_t)(int chan, void *stream, int len, void *udata);
   203 
   204 /*
   205  * This is a callback that signifies that a channel has finished all its
   206  *  loops and has completed playback. This gets called if the buffer
   207  *  plays out normally, or if you call Mix_HaltChannel(), implicitly stop
   208  *  a channel via Mix_AllocateChannels(), or unregister a callback while
   209  *  it's still playing.
   210  *
   211  * DO NOT EVER call SDL_LockAudio() from your callback function!
   212  */
   213 typedef void (*Mix_EffectDone_t)(int chan, void *udata);
   214 
   215 
   216 /* Register a special effect function. At mixing time, the channel data is
   217  *  copied into a buffer and passed through each registered effect function.
   218  *  After it passes through all the functions, it is mixed into the final
   219  *  output stream. The copy to buffer is performed once, then each effect
   220  *  function performs on the output of the previous effect. Understand that
   221  *  this extra copy to a buffer is not performed if there are no effects
   222  *  registered for a given chunk, which saves CPU cycles, and any given
   223  *  effect will be extra cycles, too, so it is crucial that your code run
   224  *  fast. Also note that the data that your function is given is in the
   225  *  format of the sound device, and not the format you gave to Mix_OpenAudio(),
   226  *  although they may in reality be the same. This is an unfortunate but
   227  *  necessary speed concern. Use Mix_QuerySpec() to determine if you can
   228  *  handle the data before you register your effect, and take appropriate
   229  *  actions.
   230  * You may also specify a callback (Mix_EffectDone_t) that is called when
   231  *  the channel finishes playing. This gives you a more fine-grained control
   232  *  than Mix_ChannelFinished(), in case you need to free effect-specific
   233  *  resources, etc. If you don't need this, you can specify NULL.
   234  * You may set the callbacks before or after calling Mix_PlayChannel().
   235  * Things like Mix_SetPanning() are just internal special effect functions,
   236  *  so if you are using that, you've already incurred the overhead of a copy
   237  *  to a separate buffer, and that these effects will be in the queue with
   238  *  any functions you've registered. The list of registered effects for a
   239  *  channel is reset when a chunk finishes playing, so you need to explicitly
   240  *  set them with each call to Mix_PlayChannel*().
   241  * You may also register a special effect function that is to be run after
   242  *  final mixing occurs. The rules for these callbacks are identical to those
   243  *  in Mix_RegisterEffect, but they are run after all the channels and the
   244  *  music have been mixed into a single stream, whereas channel-specific
   245  *  effects run on a given channel before any other mixing occurs. These
   246  *  global effect callbacks are call "posteffects". Posteffects only have
   247  *  their Mix_EffectDone_t function called when they are unregistered (since
   248  *  the main output stream is never "done" in the same sense as a channel).
   249  *  You must unregister them manually when you've had enough. Your callback
   250  *  will be told that the channel being mixed is (MIX_CHANNEL_POST) if the
   251  *  processing is considered a posteffect.
   252  *
   253  * After all these effects have finished processing, the callback registered
   254  *  through Mix_SetPostMix() runs, and then the stream goes to the audio
   255  *  device. 
   256  *
   257  * DO NOT EVER call SDL_LockAudio() from your callback function!
   258  *
   259  * returns zero if error (no such channel), nonzero if added.
   260  *  Error messages can be retrieved from Mix_GetError().
   261  */
   262 extern DECLSPEC int SDLCALL Mix_RegisterEffect(int chan, Mix_EffectFunc_t f,
   263 					Mix_EffectDone_t d, void *arg);
   264 
   265 
   266 /* You may not need to call this explicitly, unless you need to stop an
   267  *  effect from processing in the middle of a chunk's playback.
   268  * Posteffects are never implicitly unregistered as they are for channels,
   269  *  but they may be explicitly unregistered through this function by
   270  *  specifying MIX_CHANNEL_POST for a channel.
   271  * returns zero if error (no such channel or effect), nonzero if removed.
   272  *  Error messages can be retrieved from Mix_GetError().
   273  */
   274 extern DECLSPEC int SDLCALL Mix_UnregisterEffect(int channel, Mix_EffectFunc_t f);
   275 
   276 
   277 /* You may not need to call this explicitly, unless you need to stop all
   278  *  effects from processing in the middle of a chunk's playback. Note that
   279  *  this will also shut off some internal effect processing, since
   280  *  Mix_SetPanning() and others may use this API under the hood. This is
   281  *  called internally when a channel completes playback.
   282  * Posteffects are never implicitly unregistered as they are for channels,
   283  *  but they may be explicitly unregistered through this function by
   284  *  specifying MIX_CHANNEL_POST for a channel.
   285  * returns zero if error (no such channel), nonzero if all effects removed.
   286  *  Error messages can be retrieved from Mix_GetError().
   287  */
   288 extern DECLSPEC int SDLCALL Mix_UnregisterAllEffects(int channel);
   289 
   290 
   291 #define MIX_EFFECTSMAXSPEED  "MIX_EFFECTSMAXSPEED"
   292 
   293 /*
   294  * These are the internally-defined mixing effects. They use the same API that
   295  *  effects defined in the application use, but are provided here as a
   296  *  convenience. Some effects can reduce their quality or use more memory in
   297  *  the name of speed; to enable this, make sure the environment variable
   298  *  MIX_EFFECTSMAXSPEED (see above) is defined before you call
   299  *  Mix_OpenAudio().
   300  */
   301 
   302 
   303 /* Set the panning of a channel. The left and right channels are specified
   304  *  as integers between 0 and 255, quietest to loudest, respectively.
   305  *
   306  * Technically, this is just individual volume control for a sample with
   307  *  two (stereo) channels, so it can be used for more than just panning.
   308  *  If you want real panning, call it like this:
   309  *
   310  *   Mix_SetPanning(channel, left, 255 - left);
   311  *
   312  * ...which isn't so hard.
   313  *
   314  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   315  *  the panning will be done to the final mixed stream before passing it on
   316  *  to the audio device.
   317  *
   318  * This uses the Mix_RegisterEffect() API internally, and returns without
   319  *  registering the effect function if the audio device is not configured
   320  *  for stereo output. Setting both (left) and (right) to 255 causes this
   321  *  effect to be unregistered, since that is the data's normal state.
   322  *
   323  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   324  *  nonzero if panning effect enabled. Note that an audio device in mono
   325  *  mode is a no-op, but this call will return successful in that case.
   326  *  Error messages can be retrieved from Mix_GetError().
   327  */
   328 extern DECLSPEC int SDLCALL Mix_SetPanning(int channel, Uint8 left, Uint8 right);
   329 
   330 
   331 /* Set the position of a channel. (angle) is an integer from 0 to 360, that
   332  *  specifies the location of the sound in relation to the listener. (angle)
   333  *  will be reduced as neccesary (540 becomes 180 degrees, -100 becomes 260).
   334  *  Angle 0 is due north, and rotates clockwise as the value increases.
   335  *  For efficiency, the precision of this effect may be limited (angles 1
   336  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
   337  *  (distance) is an integer between 0 and 255 that specifies the space
   338  *  between the sound and the listener. The larger the number, the further
   339  *  away the sound is. Using 255 does not guarantee that the channel will be
   340  *  culled from the mixing process or be completely silent. For efficiency,
   341  *  the precision of this effect may be limited (distance 0 through 5 might
   342  *  all produce the same effect, 6 through 10 are equal, etc). Setting (angle)
   343  *  and (distance) to 0 unregisters this effect, since the data would be
   344  *  unchanged.
   345  *
   346  * If you need more precise positional audio, consider using OpenAL for
   347  *  spatialized effects instead of SDL_mixer. This is only meant to be a
   348  *  basic effect for simple "3D" games.
   349  *
   350  * If the audio device is configured for mono output, then you won't get
   351  *  any effectiveness from the angle; however, distance attenuation on the
   352  *  channel will still occur. While this effect will function with stereo
   353  *  voices, it makes more sense to use voices with only one channel of sound,
   354  *  so when they are mixed through this effect, the positioning will sound
   355  *  correct. You can convert them to mono through SDL before giving them to
   356  *  the mixer in the first place if you like.
   357  *
   358  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   359  *  the positioning will be done to the final mixed stream before passing it
   360  *  on to the audio device.
   361  *
   362  * This is a convenience wrapper over Mix_SetDistance() and Mix_SetPanning().
   363  *
   364  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   365  *  nonzero if position effect is enabled.
   366  *  Error messages can be retrieved from Mix_GetError().
   367  */
   368 extern DECLSPEC int SDLCALL Mix_SetPosition(int channel, Sint16 angle, Uint8 distance);
   369 
   370 
   371 /* Set the "distance" of a channel. (distance) is an integer from 0 to 255
   372  *  that specifies the location of the sound in relation to the listener.
   373  *  Distance 0 is overlapping the listener, and 255 is as far away as possible
   374  *  A distance of 255 does not guarantee silence; in such a case, you might
   375  *  want to try changing the chunk's volume, or just cull the sample from the
   376  *  mixing process with Mix_HaltChannel().
   377  * For efficiency, the precision of this effect may be limited (distances 1
   378  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
   379  *  (distance) is an integer between 0 and 255 that specifies the space
   380  *  between the sound and the listener. The larger the number, the further
   381  *  away the sound is.
   382  * Setting (distance) to 0 unregisters this effect, since the data would be
   383  *  unchanged.
   384  * If you need more precise positional audio, consider using OpenAL for
   385  *  spatialized effects instead of SDL_mixer. This is only meant to be a
   386  *  basic effect for simple "3D" games.
   387  *
   388  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   389  *  the distance attenuation will be done to the final mixed stream before
   390  *  passing it on to the audio device.
   391  *
   392  * This uses the Mix_RegisterEffect() API internally.
   393  *
   394  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   395  *  nonzero if position effect is enabled.
   396  *  Error messages can be retrieved from Mix_GetError().
   397  */
   398 extern DECLSPEC int SDLCALL Mix_SetDistance(int channel, Uint8 distance);
   399 
   400 
   401 /*
   402  * !!! FIXME : Haven't implemented, since the effect goes past the
   403  *              end of the sound buffer. Will have to think about this.
   404  *               --ryan.
   405  */
   406 #if 0
   407 /* Causes an echo effect to be mixed into a sound. (echo) is the amount
   408  *  of echo to mix. 0 is no echo, 255 is infinite (and probably not
   409  *  what you want).
   410  *
   411  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
   412  *  the reverbing will be done to the final mixed stream before passing it on
   413  *  to the audio device.
   414  *
   415  * This uses the Mix_RegisterEffect() API internally. If you specify an echo
   416  *  of zero, the effect is unregistered, as the data is already in that state.
   417  *
   418  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   419  *  nonzero if reversing effect is enabled.
   420  *  Error messages can be retrieved from Mix_GetError().
   421  */
   422 extern no_parse_DECLSPEC int SDLCALL Mix_SetReverb(int channel, Uint8 echo);
   423 #endif
   424 
   425 /* Causes a channel to reverse its stereo. This is handy if the user has his
   426  *  speakers hooked up backwards, or you would like to have a minor bit of
   427  *  psychedelia in your sound code.  :)  Calling this function with (flip)
   428  *  set to non-zero reverses the chunks's usual channels. If (flip) is zero,
   429  *  the effect is unregistered.
   430  *
   431  * This uses the Mix_RegisterEffect() API internally, and thus is probably
   432  *  more CPU intensive than having the user just plug in his speakers
   433  *  correctly. Mix_SetReverseStereo() returns without registering the effect
   434  *  function if the audio device is not configured for stereo output.
   435  *
   436  * If you specify MIX_CHANNEL_POST for (channel), then this the effect is used
   437  *  on the final mixed stream before sending it on to the audio device (a
   438  *  posteffect).
   439  *
   440  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
   441  *  nonzero if reversing effect is enabled. Note that an audio device in mono
   442  *  mode is a no-op, but this call will return successful in that case.
   443  *  Error messages can be retrieved from Mix_GetError().
   444  */
   445 extern DECLSPEC int SDLCALL Mix_SetReverseStereo(int channel, int flip);
   446 
   447 /* end of effects API. --ryan. */
   448 
   449 
   450 /* Reserve the first channels (0 -> n-1) for the application, i.e. don't allocate
   451    them dynamically to the next sample if requested with a -1 value below.
   452    Returns the number of reserved channels.
   453  */
   454 extern DECLSPEC int SDLCALL Mix_ReserveChannels(int num);
   455 
   456 /* Channel grouping functions */
   457 
   458 /* Attach a tag to a channel. A tag can be assigned to several mixer
   459    channels, to form groups of channels.
   460    If 'tag' is -1, the tag is removed (actually -1 is the tag used to
   461    represent the group of all the channels).
   462    Returns true if everything was OK.
   463  */
   464 extern DECLSPEC int SDLCALL Mix_GroupChannel(int which, int tag);
   465 /* Assign several consecutive channels to a group */
   466 extern DECLSPEC int SDLCALL Mix_GroupChannels(int from, int to, int tag);
   467 /* Finds the first available channel in a group of channels,
   468    returning -1 if none are available.
   469  */
   470 extern DECLSPEC int SDLCALL Mix_GroupAvailable(int tag);
   471 /* Returns the number of channels in a group. This is also a subtle
   472    way to get the total number of channels when 'tag' is -1
   473  */
   474 extern DECLSPEC int SDLCALL Mix_GroupCount(int tag);
   475 /* Finds the "oldest" sample playing in a group of channels */
   476 extern DECLSPEC int SDLCALL Mix_GroupOldest(int tag);
   477 /* Finds the "most recent" (i.e. last) sample playing in a group of channels */
   478 extern DECLSPEC int SDLCALL Mix_GroupNewer(int tag);
   479 
   480 /* Play an audio chunk on a specific channel.
   481    If the specified channel is -1, play on the first free channel.
   482    If 'loops' is greater than zero, loop the sound that many times.
   483    If 'loops' is -1, loop inifinitely (~65000 times).
   484    Returns which channel was used to play the sound.
   485 */
   486 #define Mix_PlayChannel(channel,chunk,loops) Mix_PlayChannelTimed(channel,chunk,loops,-1)
   487 /* The same as above, but the sound is played at most 'ticks' milliseconds */
   488 extern DECLSPEC int SDLCALL Mix_PlayChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ticks);
   489 extern DECLSPEC int SDLCALL Mix_PlayMusic(Mix_Music *music, int loops);
   490 
   491 /* Fade in music or a channel over "ms" milliseconds, same semantics as the "Play" functions */
   492 extern DECLSPEC int SDLCALL Mix_FadeInMusic(Mix_Music *music, int loops, int ms);
   493 extern DECLSPEC int SDLCALL Mix_FadeInMusicPos(Mix_Music *music, int loops, int ms, double position);
   494 #define Mix_FadeInChannel(channel,chunk,loops,ms) Mix_FadeInChannelTimed(channel,chunk,loops,ms,-1)
   495 extern DECLSPEC int SDLCALL Mix_FadeInChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ms, int ticks);
   496 
   497 /* Set the volume in the range of 0-128 of a specific channel or chunk.
   498    If the specified channel is -1, set volume for all channels.
   499    Returns the original volume.
   500    If the specified volume is -1, just return the current volume.
   501 */
   502 extern DECLSPEC int SDLCALL Mix_Volume(int channel, int volume);
   503 extern DECLSPEC int SDLCALL Mix_VolumeChunk(Mix_Chunk *chunk, int volume);
   504 extern DECLSPEC int SDLCALL Mix_VolumeMusic(int volume);
   505 
   506 /* Halt playing of a particular channel */
   507 extern DECLSPEC int SDLCALL Mix_HaltChannel(int channel);
   508 extern DECLSPEC int SDLCALL Mix_HaltGroup(int tag);
   509 extern DECLSPEC int SDLCALL Mix_HaltMusic(void);
   510 
   511 /* Change the expiration delay for a particular channel.
   512    The sample will stop playing after the 'ticks' milliseconds have elapsed,
   513    or remove the expiration if 'ticks' is -1
   514 */
   515 extern DECLSPEC int SDLCALL Mix_ExpireChannel(int channel, int ticks);
   516 
   517 /* Halt a channel, fading it out progressively till it's silent
   518    The ms parameter indicates the number of milliseconds the fading
   519    will take.
   520  */
   521 extern DECLSPEC int SDLCALL Mix_FadeOutChannel(int which, int ms);
   522 extern DECLSPEC int SDLCALL Mix_FadeOutGroup(int tag, int ms);
   523 extern DECLSPEC int SDLCALL Mix_FadeOutMusic(int ms);
   524 
   525 /* Query the fading status of a channel */
   526 extern DECLSPEC Mix_Fading SDLCALL Mix_FadingMusic(void);
   527 extern DECLSPEC Mix_Fading SDLCALL Mix_FadingChannel(int which);
   528 
   529 /* Pause/Resume a particular channel */
   530 extern DECLSPEC void SDLCALL Mix_Pause(int channel);
   531 extern DECLSPEC void SDLCALL Mix_Resume(int channel);
   532 extern DECLSPEC int SDLCALL Mix_Paused(int channel);
   533 
   534 /* Pause/Resume the music stream */
   535 extern DECLSPEC void SDLCALL Mix_PauseMusic(void);
   536 extern DECLSPEC void SDLCALL Mix_ResumeMusic(void);
   537 extern DECLSPEC void SDLCALL Mix_RewindMusic(void);
   538 extern DECLSPEC int SDLCALL Mix_PausedMusic(void);
   539 
   540 /* Set the current position in the music stream.
   541    This returns 0 if successful, or -1 if it failed or isn't implemented.
   542    This function is only implemented for MOD music formats (set pattern
   543    order number) and for OGG music (set position in seconds), at the
   544    moment.
   545 */
   546 extern DECLSPEC int SDLCALL Mix_SetMusicPosition(double position);
   547 
   548 /* Check the status of a specific channel.
   549    If the specified channel is -1, check all channels.
   550 */
   551 extern DECLSPEC int SDLCALL Mix_Playing(int channel);
   552 extern DECLSPEC int SDLCALL Mix_PlayingMusic(void);
   553 
   554 /* Stop music and set external music playback command */
   555 extern DECLSPEC int SDLCALL Mix_SetMusicCMD(const char *command);
   556 
   557 /* Synchro value is set by MikMod from modules while playing */
   558 extern DECLSPEC int SDLCALL Mix_SetSynchroValue(int value);
   559 extern DECLSPEC int SDLCALL Mix_GetSynchroValue(void);
   560 
   561 /* Get the Mix_Chunk currently associated with a mixer channel
   562     Returns NULL if it's an invalid channel, or there's no chunk associated.
   563 */
   564 extern DECLSPEC Mix_Chunk * SDLCALL Mix_GetChunk(int channel);
   565 
   566 /* Close the mixer, halting all playing audio */
   567 extern DECLSPEC void SDLCALL Mix_CloseAudio(void);
   568 
   569 /* We'll use SDL for reporting errors */
   570 #define Mix_SetError	SDL_SetError
   571 #define Mix_GetError	SDL_GetError
   572 
   573 /* Ends C function definitions when using C++ */
   574 #ifdef __cplusplus
   575 }
   576 #endif
   577 #include "close_code.h"
   578 
   579 #endif /* _MIXER_H_ */
   580 
   581 /* end of SDL_mixer.h ... */
   582