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  1. /*
  2.     SDL_mixer:  An audio mixer library based on the SDL library
  3.     Copyright (C) 1997-2009 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: SDL_mixer.h 5252 2009-11-15 09:41:26Z slouken $ */
  24.  
  25. #ifndef _SDL_MIXER_H
  26. #define _SDL_MIXER_H
  27.  
  28. #include "SDL_types.h"
  29. #include "SDL_rwops.h"
  30. #include "SDL_audio.h"
  31. #include "SDL_endian.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 SDL_MIXER_MAJOR_VERSION 1
  43. #define SDL_MIXER_MINOR_VERSION 2
  44. #define SDL_MIXER_PATCHLEVEL    11
  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 SDL_MIXER_VERSION(X)                                            \
  50. {                                                                       \
  51.         (X)->major = SDL_MIXER_MAJOR_VERSION;                           \
  52.         (X)->minor = SDL_MIXER_MINOR_VERSION;                           \
  53.         (X)->patch = SDL_MIXER_PATCHLEVEL;                              \
  54. }
  55.  
  56. /* Backwards compatibility */
  57. #define MIX_MAJOR_VERSION       SDL_MIXER_MAJOR_VERSION
  58. #define MIX_MINOR_VERSION       SDL_MIXER_MINOR_VERSION
  59. #define MIX_PATCHLEVEL          SDL_MIXER_PATCHLEVEL
  60. #define MIX_VERSION(X)          SDL_MIXER_VERSION(X)
  61.  
  62. /* This function gets the version of the dynamically linked SDL_mixer library.
  63.    it should NOT be used to fill a version structure, instead you should
  64.    use the SDL_MIXER_VERSION() macro.
  65.  */
  66. extern DECLSPEC const SDL_version * SDLCALL Mix_Linked_Version(void);
  67.  
  68. typedef enum
  69. {
  70.     MIX_INIT_FLAC = 0x00000001,
  71.     MIX_INIT_MOD  = 0x00000002,
  72.     MIX_INIT_MP3  = 0x00000004,
  73.     MIX_INIT_OGG  = 0x00000008
  74. } MIX_InitFlags;
  75.  
  76. /* Loads dynamic libraries and prepares them for use.  Flags should be
  77.    one or more flags from MIX_InitFlags OR'd together.
  78.    It returns the flags successfully initialized, or 0 on failure.
  79.  */
  80. extern DECLSPEC int SDLCALL Mix_Init(int flags);
  81.  
  82. /* Unloads libraries loaded with Mix_Init */
  83. extern DECLSPEC void SDLCALL Mix_Quit(void);
  84.  
  85.  
  86. /* The default mixer has 8 simultaneous mixing channels */
  87. #ifndef MIX_CHANNELS
  88. #define MIX_CHANNELS    8
  89. #endif
  90.  
  91. /* Good default values for a PC soundcard */
  92. #define MIX_DEFAULT_FREQUENCY   22050
  93. #if SDL_BYTEORDER == SDL_LIL_ENDIAN
  94. #define MIX_DEFAULT_FORMAT      AUDIO_S16LSB
  95. #else
  96. #define MIX_DEFAULT_FORMAT      AUDIO_S16MSB
  97. #endif
  98. #define MIX_DEFAULT_CHANNELS    2
  99. #define MIX_MAX_VOLUME          128     /* Volume of a chunk */
  100.  
  101. /* The internal format for an audio chunk */
  102. typedef struct Mix_Chunk {
  103.         int allocated;
  104.         Uint8 *abuf;
  105.         Uint32 alen;
  106.         Uint8 volume;           /* Per-sample volume, 0-128 */
  107. } Mix_Chunk;
  108.  
  109. /* The different fading types supported */
  110. typedef enum {
  111.         MIX_NO_FADING,
  112.         MIX_FADING_OUT,
  113.         MIX_FADING_IN
  114. } Mix_Fading;
  115.  
  116. typedef enum {
  117.         MUS_NONE,
  118.         MUS_CMD,
  119.         MUS_WAV,
  120.         MUS_MOD,
  121.         MUS_MID,
  122.         MUS_OGG,
  123.         MUS_MP3,
  124.         MUS_MP3_MAD,
  125.         MUS_FLAC
  126. } Mix_MusicType;
  127.  
  128. /* The internal format for a music chunk interpreted via mikmod */
  129. typedef struct _Mix_Music Mix_Music;
  130.  
  131. /* Open the mixer with a certain audio format */
  132. extern DECLSPEC int SDLCALL Mix_OpenAudio(int frequency, Uint16 format, int channels,
  133.                                                         int chunksize);
  134.  
  135. /* Dynamically change the number of channels managed by the mixer.
  136.    If decreasing the number of channels, the upper channels are
  137.    stopped.
  138.    This function returns the new number of allocated channels.
  139.  */
  140. extern DECLSPEC int SDLCALL Mix_AllocateChannels(int numchans);
  141.  
  142. /* Find out what the actual audio device parameters are.
  143.    This function returns 1 if the audio has been opened, 0 otherwise.
  144.  */
  145. extern DECLSPEC int SDLCALL Mix_QuerySpec(int *frequency,Uint16 *format,int *channels);
  146.  
  147. /* Load a wave file or a music (.mod .s3m .it .xm) file */
  148. extern DECLSPEC Mix_Chunk * SDLCALL Mix_LoadWAV_RW(SDL_RWops *src, int freesrc);
  149. #define Mix_LoadWAV(file)       Mix_LoadWAV_RW(SDL_RWFromFile(file, "rb"), 1)
  150. extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS(const char *file);
  151.  
  152. /* Load a music file from an SDL_RWop object (Ogg and MikMod specific currently)
  153.    Matt Campbell (matt@campbellhome.dhs.org) April 2000 */
  154. extern DECLSPEC Mix_Music * SDLCALL Mix_LoadMUS_RW(SDL_RWops *rw);
  155.  
  156. /* Load a wave file of the mixer format from a memory buffer */
  157. extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_WAV(Uint8 *mem);
  158.  
  159. /* Load raw audio data of the mixer format from a memory buffer */
  160. extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_RAW(Uint8 *mem, Uint32 len);
  161.  
  162. /* Free an audio chunk previously loaded */
  163. extern DECLSPEC void SDLCALL Mix_FreeChunk(Mix_Chunk *chunk);
  164. extern DECLSPEC void SDLCALL Mix_FreeMusic(Mix_Music *music);
  165.  
  166. /* Get a list of chunk/music decoders that this build of SDL_mixer provides.
  167.    This list can change between builds AND runs of the program, if external
  168.    libraries that add functionality become available.
  169.    You must successfully call Mix_OpenAudio() before calling these functions.
  170.    This API is only available in SDL_mixer 1.2.9 and later.
  171.  
  172.    // usage...
  173.    int i;
  174.    const int total = Mix_GetNumChunkDecoders();
  175.    for (i = 0; i < total; i++)
  176.        printf("Supported chunk decoder: [%s]\n", Mix_GetChunkDecoder(i));
  177.  
  178.    Appearing in this list doesn't promise your specific audio file will
  179.    decode...but it's handy to know if you have, say, a functioning Timidity
  180.    install.
  181.  
  182.    These return values are static, read-only data; do not modify or free it.
  183.    The pointers remain valid until you call Mix_CloseAudio().
  184. */
  185. extern DECLSPEC int SDLCALL Mix_GetNumChunkDecoders(void);
  186. extern DECLSPEC const char * SDLCALL Mix_GetChunkDecoder(int index);
  187. extern DECLSPEC int SDLCALL Mix_GetNumMusicDecoders(void);
  188. extern DECLSPEC const char * SDLCALL Mix_GetMusicDecoder(int index);
  189.  
  190. /* Find out the music format of a mixer music, or the currently playing
  191.    music, if 'music' is NULL.
  192. */
  193. extern DECLSPEC Mix_MusicType SDLCALL Mix_GetMusicType(const Mix_Music *music);
  194.  
  195. /* Set a function that is called after all mixing is performed.
  196.    This can be used to provide real-time visual display of the audio stream
  197.    or add a custom mixer filter for the stream data.
  198. */
  199. extern DECLSPEC void SDLCALL Mix_SetPostMix(void (*mix_func)
  200.                              (void *udata, Uint8 *stream, int len), void *arg);
  201.  
  202. /* Add your own music player or additional mixer function.
  203.    If 'mix_func' is NULL, the default music player is re-enabled.
  204.  */
  205. extern DECLSPEC void SDLCALL Mix_HookMusic(void (*mix_func)
  206.                           (void *udata, Uint8 *stream, int len), void *arg);
  207.  
  208. /* Add your own callback when the music has finished playing.
  209.    This callback is only called if the music finishes naturally.
  210.  */
  211. extern DECLSPEC void SDLCALL Mix_HookMusicFinished(void (*music_finished)(void));
  212.  
  213. /* Get a pointer to the user data for the current music hook */
  214. extern DECLSPEC void * SDLCALL Mix_GetMusicHookData(void);
  215.  
  216. /*
  217.  * Add your own callback when a channel has finished playing. NULL
  218.  *  to disable callback. The callback may be called from the mixer's audio
  219.  *  callback or it could be called as a result of Mix_HaltChannel(), etc.
  220.  *  do not call SDL_LockAudio() from this callback; you will either be
  221.  *  inside the audio callback, or SDL_mixer will explicitly lock the audio
  222.  *  before calling your callback.
  223.  */
  224. extern DECLSPEC void SDLCALL Mix_ChannelFinished(void (*channel_finished)(int channel));
  225.  
  226.  
  227. /* Special Effects API by ryan c. gordon. (icculus@icculus.org) */
  228.  
  229. #define MIX_CHANNEL_POST  -2
  230.  
  231. /* This is the format of a special effect callback:
  232.  *
  233.  *   myeffect(int chan, void *stream, int len, void *udata);
  234.  *
  235.  * (chan) is the channel number that your effect is affecting. (stream) is
  236.  *  the buffer of data to work upon. (len) is the size of (stream), and
  237.  *  (udata) is a user-defined bit of data, which you pass as the last arg of
  238.  *  Mix_RegisterEffect(), and is passed back unmolested to your callback.
  239.  *  Your effect changes the contents of (stream) based on whatever parameters
  240.  *  are significant, or just leaves it be, if you prefer. You can do whatever
  241.  *  you like to the buffer, though, and it will continue in its changed state
  242.  *  down the mixing pipeline, through any other effect functions, then finally
  243.  *  to be mixed with the rest of the channels and music for the final output
  244.  *  stream.
  245.  *
  246.  * DO NOT EVER call SDL_LockAudio() from your callback function!
  247.  */
  248. typedef void (*Mix_EffectFunc_t)(int chan, void *stream, int len, void *udata);
  249.  
  250. /*
  251.  * This is a callback that signifies that a channel has finished all its
  252.  *  loops and has completed playback. This gets called if the buffer
  253.  *  plays out normally, or if you call Mix_HaltChannel(), implicitly stop
  254.  *  a channel via Mix_AllocateChannels(), or unregister a callback while
  255.  *  it's still playing.
  256.  *
  257.  * DO NOT EVER call SDL_LockAudio() from your callback function!
  258.  */
  259. typedef void (*Mix_EffectDone_t)(int chan, void *udata);
  260.  
  261.  
  262. /* Register a special effect function. At mixing time, the channel data is
  263.  *  copied into a buffer and passed through each registered effect function.
  264.  *  After it passes through all the functions, it is mixed into the final
  265.  *  output stream. The copy to buffer is performed once, then each effect
  266.  *  function performs on the output of the previous effect. Understand that
  267.  *  this extra copy to a buffer is not performed if there are no effects
  268.  *  registered for a given chunk, which saves CPU cycles, and any given
  269.  *  effect will be extra cycles, too, so it is crucial that your code run
  270.  *  fast. Also note that the data that your function is given is in the
  271.  *  format of the sound device, and not the format you gave to Mix_OpenAudio(),
  272.  *  although they may in reality be the same. This is an unfortunate but
  273.  *  necessary speed concern. Use Mix_QuerySpec() to determine if you can
  274.  *  handle the data before you register your effect, and take appropriate
  275.  *  actions.
  276.  * You may also specify a callback (Mix_EffectDone_t) that is called when
  277.  *  the channel finishes playing. This gives you a more fine-grained control
  278.  *  than Mix_ChannelFinished(), in case you need to free effect-specific
  279.  *  resources, etc. If you don't need this, you can specify NULL.
  280.  * You may set the callbacks before or after calling Mix_PlayChannel().
  281.  * Things like Mix_SetPanning() are just internal special effect functions,
  282.  *  so if you are using that, you've already incurred the overhead of a copy
  283.  *  to a separate buffer, and that these effects will be in the queue with
  284.  *  any functions you've registered. The list of registered effects for a
  285.  *  channel is reset when a chunk finishes playing, so you need to explicitly
  286.  *  set them with each call to Mix_PlayChannel*().
  287.  * You may also register a special effect function that is to be run after
  288.  *  final mixing occurs. The rules for these callbacks are identical to those
  289.  *  in Mix_RegisterEffect, but they are run after all the channels and the
  290.  *  music have been mixed into a single stream, whereas channel-specific
  291.  *  effects run on a given channel before any other mixing occurs. These
  292.  *  global effect callbacks are call "posteffects". Posteffects only have
  293.  *  their Mix_EffectDone_t function called when they are unregistered (since
  294.  *  the main output stream is never "done" in the same sense as a channel).
  295.  *  You must unregister them manually when you've had enough. Your callback
  296.  *  will be told that the channel being mixed is (MIX_CHANNEL_POST) if the
  297.  *  processing is considered a posteffect.
  298.  *
  299.  * After all these effects have finished processing, the callback registered
  300.  *  through Mix_SetPostMix() runs, and then the stream goes to the audio
  301.  *  device.
  302.  *
  303.  * DO NOT EVER call SDL_LockAudio() from your callback function!
  304.  *
  305.  * returns zero if error (no such channel), nonzero if added.
  306.  *  Error messages can be retrieved from Mix_GetError().
  307.  */
  308. extern DECLSPEC int SDLCALL Mix_RegisterEffect(int chan, Mix_EffectFunc_t f,
  309.                                         Mix_EffectDone_t d, void *arg);
  310.  
  311.  
  312. /* You may not need to call this explicitly, unless you need to stop an
  313.  *  effect from processing in the middle of a chunk's playback.
  314.  * Posteffects are never implicitly unregistered as they are for channels,
  315.  *  but they may be explicitly unregistered through this function by
  316.  *  specifying MIX_CHANNEL_POST for a channel.
  317.  * returns zero if error (no such channel or effect), nonzero if removed.
  318.  *  Error messages can be retrieved from Mix_GetError().
  319.  */
  320. extern DECLSPEC int SDLCALL Mix_UnregisterEffect(int channel, Mix_EffectFunc_t f);
  321.  
  322.  
  323. /* You may not need to call this explicitly, unless you need to stop all
  324.  *  effects from processing in the middle of a chunk's playback. Note that
  325.  *  this will also shut off some internal effect processing, since
  326.  *  Mix_SetPanning() and others may use this API under the hood. This is
  327.  *  called internally when a channel completes playback.
  328.  * Posteffects are never implicitly unregistered as they are for channels,
  329.  *  but they may be explicitly unregistered through this function by
  330.  *  specifying MIX_CHANNEL_POST for a channel.
  331.  * returns zero if error (no such channel), nonzero if all effects removed.
  332.  *  Error messages can be retrieved from Mix_GetError().
  333.  */
  334. extern DECLSPEC int SDLCALL Mix_UnregisterAllEffects(int channel);
  335.  
  336.  
  337. #define MIX_EFFECTSMAXSPEED  "MIX_EFFECTSMAXSPEED"
  338.  
  339. /*
  340.  * These are the internally-defined mixing effects. They use the same API that
  341.  *  effects defined in the application use, but are provided here as a
  342.  *  convenience. Some effects can reduce their quality or use more memory in
  343.  *  the name of speed; to enable this, make sure the environment variable
  344.  *  MIX_EFFECTSMAXSPEED (see above) is defined before you call
  345.  *  Mix_OpenAudio().
  346.  */
  347.  
  348.  
  349. /* Set the panning of a channel. The left and right channels are specified
  350.  *  as integers between 0 and 255, quietest to loudest, respectively.
  351.  *
  352.  * Technically, this is just individual volume control for a sample with
  353.  *  two (stereo) channels, so it can be used for more than just panning.
  354.  *  If you want real panning, call it like this:
  355.  *
  356.  *   Mix_SetPanning(channel, left, 255 - left);
  357.  *
  358.  * ...which isn't so hard.
  359.  *
  360.  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
  361.  *  the panning will be done to the final mixed stream before passing it on
  362.  *  to the audio device.
  363.  *
  364.  * This uses the Mix_RegisterEffect() API internally, and returns without
  365.  *  registering the effect function if the audio device is not configured
  366.  *  for stereo output. Setting both (left) and (right) to 255 causes this
  367.  *  effect to be unregistered, since that is the data's normal state.
  368.  *
  369.  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
  370.  *  nonzero if panning effect enabled. Note that an audio device in mono
  371.  *  mode is a no-op, but this call will return successful in that case.
  372.  *  Error messages can be retrieved from Mix_GetError().
  373.  */
  374. extern DECLSPEC int SDLCALL Mix_SetPanning(int channel, Uint8 left, Uint8 right);
  375.  
  376.  
  377. /* Set the position of a channel. (angle) is an integer from 0 to 360, that
  378.  *  specifies the location of the sound in relation to the listener. (angle)
  379.  *  will be reduced as neccesary (540 becomes 180 degrees, -100 becomes 260).
  380.  *  Angle 0 is due north, and rotates clockwise as the value increases.
  381.  *  For efficiency, the precision of this effect may be limited (angles 1
  382.  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
  383.  *  (distance) is an integer between 0 and 255 that specifies the space
  384.  *  between the sound and the listener. The larger the number, the further
  385.  *  away the sound is. Using 255 does not guarantee that the channel will be
  386.  *  culled from the mixing process or be completely silent. For efficiency,
  387.  *  the precision of this effect may be limited (distance 0 through 5 might
  388.  *  all produce the same effect, 6 through 10 are equal, etc). Setting (angle)
  389.  *  and (distance) to 0 unregisters this effect, since the data would be
  390.  *  unchanged.
  391.  *
  392.  * If you need more precise positional audio, consider using OpenAL for
  393.  *  spatialized effects instead of SDL_mixer. This is only meant to be a
  394.  *  basic effect for simple "3D" games.
  395.  *
  396.  * If the audio device is configured for mono output, then you won't get
  397.  *  any effectiveness from the angle; however, distance attenuation on the
  398.  *  channel will still occur. While this effect will function with stereo
  399.  *  voices, it makes more sense to use voices with only one channel of sound,
  400.  *  so when they are mixed through this effect, the positioning will sound
  401.  *  correct. You can convert them to mono through SDL before giving them to
  402.  *  the mixer in the first place if you like.
  403.  *
  404.  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
  405.  *  the positioning will be done to the final mixed stream before passing it
  406.  *  on to the audio device.
  407.  *
  408.  * This is a convenience wrapper over Mix_SetDistance() and Mix_SetPanning().
  409.  *
  410.  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
  411.  *  nonzero if position effect is enabled.
  412.  *  Error messages can be retrieved from Mix_GetError().
  413.  */
  414. extern DECLSPEC int SDLCALL Mix_SetPosition(int channel, Sint16 angle, Uint8 distance);
  415.  
  416.  
  417. /* Set the "distance" of a channel. (distance) is an integer from 0 to 255
  418.  *  that specifies the location of the sound in relation to the listener.
  419.  *  Distance 0 is overlapping the listener, and 255 is as far away as possible
  420.  *  A distance of 255 does not guarantee silence; in such a case, you might
  421.  *  want to try changing the chunk's volume, or just cull the sample from the
  422.  *  mixing process with Mix_HaltChannel().
  423.  * For efficiency, the precision of this effect may be limited (distances 1
  424.  *  through 7 might all produce the same effect, 8 through 15 are equal, etc).
  425.  *  (distance) is an integer between 0 and 255 that specifies the space
  426.  *  between the sound and the listener. The larger the number, the further
  427.  *  away the sound is.
  428.  * Setting (distance) to 0 unregisters this effect, since the data would be
  429.  *  unchanged.
  430.  * If you need more precise positional audio, consider using OpenAL for
  431.  *  spatialized effects instead of SDL_mixer. This is only meant to be a
  432.  *  basic effect for simple "3D" games.
  433.  *
  434.  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
  435.  *  the distance attenuation will be done to the final mixed stream before
  436.  *  passing it on to the audio device.
  437.  *
  438.  * This uses the Mix_RegisterEffect() API internally.
  439.  *
  440.  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
  441.  *  nonzero if position effect is enabled.
  442.  *  Error messages can be retrieved from Mix_GetError().
  443.  */
  444. extern DECLSPEC int SDLCALL Mix_SetDistance(int channel, Uint8 distance);
  445.  
  446.  
  447. /*
  448.  * !!! FIXME : Haven't implemented, since the effect goes past the
  449.  *              end of the sound buffer. Will have to think about this.
  450.  *               --ryan.
  451.  */
  452. #if 0
  453. /* Causes an echo effect to be mixed into a sound. (echo) is the amount
  454.  *  of echo to mix. 0 is no echo, 255 is infinite (and probably not
  455.  *  what you want).
  456.  *
  457.  * Setting (channel) to MIX_CHANNEL_POST registers this as a posteffect, and
  458.  *  the reverbing will be done to the final mixed stream before passing it on
  459.  *  to the audio device.
  460.  *
  461.  * This uses the Mix_RegisterEffect() API internally. If you specify an echo
  462.  *  of zero, the effect is unregistered, as the data is already in that state.
  463.  *
  464.  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
  465.  *  nonzero if reversing effect is enabled.
  466.  *  Error messages can be retrieved from Mix_GetError().
  467.  */
  468. extern no_parse_DECLSPEC int SDLCALL Mix_SetReverb(int channel, Uint8 echo);
  469. #endif
  470.  
  471. /* Causes a channel to reverse its stereo. This is handy if the user has his
  472.  *  speakers hooked up backwards, or you would like to have a minor bit of
  473.  *  psychedelia in your sound code.  :)  Calling this function with (flip)
  474.  *  set to non-zero reverses the chunks's usual channels. If (flip) is zero,
  475.  *  the effect is unregistered.
  476.  *
  477.  * This uses the Mix_RegisterEffect() API internally, and thus is probably
  478.  *  more CPU intensive than having the user just plug in his speakers
  479.  *  correctly. Mix_SetReverseStereo() returns without registering the effect
  480.  *  function if the audio device is not configured for stereo output.
  481.  *
  482.  * If you specify MIX_CHANNEL_POST for (channel), then this the effect is used
  483.  *  on the final mixed stream before sending it on to the audio device (a
  484.  *  posteffect).
  485.  *
  486.  * returns zero if error (no such channel or Mix_RegisterEffect() fails),
  487.  *  nonzero if reversing effect is enabled. Note that an audio device in mono
  488.  *  mode is a no-op, but this call will return successful in that case.
  489.  *  Error messages can be retrieved from Mix_GetError().
  490.  */
  491. extern DECLSPEC int SDLCALL Mix_SetReverseStereo(int channel, int flip);
  492.  
  493. /* end of effects API. --ryan. */
  494.  
  495.  
  496. /* Reserve the first channels (0 -> n-1) for the application, i.e. don't allocate
  497.    them dynamically to the next sample if requested with a -1 value below.
  498.    Returns the number of reserved channels.
  499.  */
  500. extern DECLSPEC int SDLCALL Mix_ReserveChannels(int num);
  501.  
  502. /* Channel grouping functions */
  503.  
  504. /* Attach a tag to a channel. A tag can be assigned to several mixer
  505.    channels, to form groups of channels.
  506.    If 'tag' is -1, the tag is removed (actually -1 is the tag used to
  507.    represent the group of all the channels).
  508.    Returns true if everything was OK.
  509.  */
  510. extern DECLSPEC int SDLCALL Mix_GroupChannel(int which, int tag);
  511. /* Assign several consecutive channels to a group */
  512. extern DECLSPEC int SDLCALL Mix_GroupChannels(int from, int to, int tag);
  513. /* Finds the first available channel in a group of channels,
  514.    returning -1 if none are available.
  515.  */
  516. extern DECLSPEC int SDLCALL Mix_GroupAvailable(int tag);
  517. /* Returns the number of channels in a group. This is also a subtle
  518.    way to get the total number of channels when 'tag' is -1
  519.  */
  520. extern DECLSPEC int SDLCALL Mix_GroupCount(int tag);
  521. /* Finds the "oldest" sample playing in a group of channels */
  522. extern DECLSPEC int SDLCALL Mix_GroupOldest(int tag);
  523. /* Finds the "most recent" (i.e. last) sample playing in a group of channels */
  524. extern DECLSPEC int SDLCALL Mix_GroupNewer(int tag);
  525.  
  526. /* Play an audio chunk on a specific channel.
  527.    If the specified channel is -1, play on the first free channel.
  528.    If 'loops' is greater than zero, loop the sound that many times.
  529.    If 'loops' is -1, loop inifinitely (~65000 times).
  530.    Returns which channel was used to play the sound.
  531. */
  532. #define Mix_PlayChannel(channel,chunk,loops) Mix_PlayChannelTimed(channel,chunk,loops,-1)
  533. /* The same as above, but the sound is played at most 'ticks' milliseconds */
  534. extern DECLSPEC int SDLCALL Mix_PlayChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ticks);
  535. extern DECLSPEC int SDLCALL Mix_PlayMusic(Mix_Music *music, int loops);
  536.  
  537. /* Fade in music or a channel over "ms" milliseconds, same semantics as the "Play" functions */
  538. extern DECLSPEC int SDLCALL Mix_FadeInMusic(Mix_Music *music, int loops, int ms);
  539. extern DECLSPEC int SDLCALL Mix_FadeInMusicPos(Mix_Music *music, int loops, int ms, double position);
  540. #define Mix_FadeInChannel(channel,chunk,loops,ms) Mix_FadeInChannelTimed(channel,chunk,loops,ms,-1)
  541. extern DECLSPEC int SDLCALL Mix_FadeInChannelTimed(int channel, Mix_Chunk *chunk, int loops, int ms, int ticks);
  542.  
  543. /* Set the volume in the range of 0-128 of a specific channel or chunk.
  544.    If the specified channel is -1, set volume for all channels.
  545.    Returns the original volume.
  546.    If the specified volume is -1, just return the current volume.
  547. */
  548. extern DECLSPEC int SDLCALL Mix_Volume(int channel, int volume);
  549. extern DECLSPEC int SDLCALL Mix_VolumeChunk(Mix_Chunk *chunk, int volume);
  550. extern DECLSPEC int SDLCALL Mix_VolumeMusic(int volume);
  551.  
  552. /* Halt playing of a particular channel */
  553. extern DECLSPEC int SDLCALL Mix_HaltChannel(int channel);
  554. extern DECLSPEC int SDLCALL Mix_HaltGroup(int tag);
  555. extern DECLSPEC int SDLCALL Mix_HaltMusic(void);
  556.  
  557. /* Change the expiration delay for a particular channel.
  558.    The sample will stop playing after the 'ticks' milliseconds have elapsed,
  559.    or remove the expiration if 'ticks' is -1
  560. */
  561. extern DECLSPEC int SDLCALL Mix_ExpireChannel(int channel, int ticks);
  562.  
  563. /* Halt a channel, fading it out progressively till it's silent
  564.    The ms parameter indicates the number of milliseconds the fading
  565.    will take.
  566.  */
  567. extern DECLSPEC int SDLCALL Mix_FadeOutChannel(int which, int ms);
  568. extern DECLSPEC int SDLCALL Mix_FadeOutGroup(int tag, int ms);
  569. extern DECLSPEC int SDLCALL Mix_FadeOutMusic(int ms);
  570.  
  571. /* Query the fading status of a channel */
  572. extern DECLSPEC Mix_Fading SDLCALL Mix_FadingMusic(void);
  573. extern DECLSPEC Mix_Fading SDLCALL Mix_FadingChannel(int which);
  574.  
  575. /* Pause/Resume a particular channel */
  576. extern DECLSPEC void SDLCALL Mix_Pause(int channel);
  577. extern DECLSPEC void SDLCALL Mix_Resume(int channel);
  578. extern DECLSPEC int SDLCALL Mix_Paused(int channel);
  579.  
  580. /* Pause/Resume the music stream */
  581. extern DECLSPEC void SDLCALL Mix_PauseMusic(void);
  582. extern DECLSPEC void SDLCALL Mix_ResumeMusic(void);
  583. extern DECLSPEC void SDLCALL Mix_RewindMusic(void);
  584. extern DECLSPEC int SDLCALL Mix_PausedMusic(void);
  585.  
  586. /* Set the current position in the music stream.
  587.    This returns 0 if successful, or -1 if it failed or isn't implemented.
  588.    This function is only implemented for MOD music formats (set pattern
  589.    order number) and for OGG music (set position in seconds), at the
  590.    moment.
  591. */
  592. extern DECLSPEC int SDLCALL Mix_SetMusicPosition(double position);
  593.  
  594. /* Check the status of a specific channel.
  595.    If the specified channel is -1, check all channels.
  596. */
  597. extern DECLSPEC int SDLCALL Mix_Playing(int channel);
  598. extern DECLSPEC int SDLCALL Mix_PlayingMusic(void);
  599.  
  600. /* Stop music and set external music playback command */
  601. extern DECLSPEC int SDLCALL Mix_SetMusicCMD(const char *command);
  602.  
  603. /* Synchro value is set by MikMod from modules while playing */
  604. extern DECLSPEC int SDLCALL Mix_SetSynchroValue(int value);
  605. extern DECLSPEC int SDLCALL Mix_GetSynchroValue(void);
  606.  
  607. /* Get the Mix_Chunk currently associated with a mixer channel
  608.     Returns NULL if it's an invalid channel, or there's no chunk associated.
  609. */
  610. extern DECLSPEC Mix_Chunk * SDLCALL Mix_GetChunk(int channel);
  611.  
  612. /* Close the mixer, halting all playing audio */
  613. extern DECLSPEC void SDLCALL Mix_CloseAudio(void);
  614.  
  615. /* We'll use SDL for reporting errors */
  616. #define Mix_SetError    SDL_SetError
  617. #define Mix_GetError    SDL_GetError
  618.  
  619. /* Ends C function definitions when using C++ */
  620. #ifdef __cplusplus
  621. }
  622. #endif
  623. #include "close_code.h"
  624.  
  625. #endif /* _SDL_MIXER_H */
  626.