include/SDL_audio.h
changeset 1895 c121d94672cb
parent 1358 c71e05b4dc2e
child 1964 071b6598d48f
equal deleted inserted replaced
1894:c69cee13dd76 1895:c121d94672cb
    18 
    18 
    19     Sam Lantinga
    19     Sam Lantinga
    20     slouken@libsdl.org
    20     slouken@libsdl.org
    21 */
    21 */
    22 
    22 
    23 /* Access to the raw audio mixing buffer for the SDL library */
    23 /**
       
    24  * \file SDL_audio.h
       
    25  *
       
    26  * Access to the raw audio mixing buffer for the SDL library
       
    27  */
    24 
    28 
    25 #ifndef _SDL_audio_h
    29 #ifndef _SDL_audio_h
    26 #define _SDL_audio_h
    30 #define _SDL_audio_h
    27 
    31 
    28 #include "SDL_stdinc.h"
    32 #include "SDL_stdinc.h"
    33 #include "SDL_rwops.h"
    37 #include "SDL_rwops.h"
    34 
    38 
    35 #include "begin_code.h"
    39 #include "begin_code.h"
    36 /* Set up for C function definitions, even when using C++ */
    40 /* Set up for C function definitions, even when using C++ */
    37 #ifdef __cplusplus
    41 #ifdef __cplusplus
       
    42 /* *INDENT-OFF* */
    38 extern "C" {
    43 extern "C" {
       
    44 /* *INDENT-ON* */
    39 #endif
    45 #endif
    40 
    46 
    41 /* The calculated values in this structure are calculated by SDL_OpenAudio() */
    47 /* The calculated values in this structure are calculated by SDL_OpenAudio() */
    42 typedef struct SDL_AudioSpec {
    48 typedef struct SDL_AudioSpec
    43 	int freq;		/* DSP frequency -- samples per second */
    49 {
    44 	Uint16 format;		/* Audio data format */
    50     int freq;                   /* DSP frequency -- samples per second */
    45 	Uint8  channels;	/* Number of channels: 1 mono, 2 stereo */
    51     Uint16 format;              /* Audio data format */
    46 	Uint8  silence;		/* Audio buffer silence value (calculated) */
    52     Uint8 channels;             /* Number of channels: 1 mono, 2 stereo */
    47 	Uint16 samples;		/* Audio buffer size in samples (power of 2) */
    53     Uint8 silence;              /* Audio buffer silence value (calculated) */
    48 	Uint16 padding;		/* Necessary for some compile environments */
    54     Uint16 samples;             /* Audio buffer size in samples (power of 2) */
    49 	Uint32 size;		/* Audio buffer size in bytes (calculated) */
    55     Uint16 padding;             /* Necessary for some compile environments */
    50 	/* This function is called when the audio device needs more data.
    56     Uint32 size;                /* Audio buffer size in bytes (calculated) */
    51 	   'stream' is a pointer to the audio data buffer
    57     /* This function is called when the audio device needs more data.
    52 	   'len' is the length of that buffer in bytes.
    58        'stream' is a pointer to the audio data buffer
    53 	   Once the callback returns, the buffer will no longer be valid.
    59        'len' is the length of that buffer in bytes.
    54 	   Stereo samples are stored in a LRLRLR ordering.
    60        Once the callback returns, the buffer will no longer be valid.
    55 	*/
    61        Stereo samples are stored in a LRLRLR ordering.
    56 	void (SDLCALL *callback)(void *userdata, Uint8 *stream, int len);
    62      */
    57 	void  *userdata;
    63     void (SDLCALL * callback) (void *userdata, Uint8 * stream, int len);
       
    64     void *userdata;
    58 } SDL_AudioSpec;
    65 } SDL_AudioSpec;
    59 
    66 
    60 /* Audio format flags (defaults to LSB byte order) */
    67 /* Audio format flags (defaults to LSB byte order) */
    61 #define AUDIO_U8	0x0008	/* Unsigned 8-bit samples */
    68 #define AUDIO_U8	0x0008  /* Unsigned 8-bit samples */
    62 #define AUDIO_S8	0x8008	/* Signed 8-bit samples */
    69 #define AUDIO_S8	0x8008  /* Signed 8-bit samples */
    63 #define AUDIO_U16LSB	0x0010	/* Unsigned 16-bit samples */
    70 #define AUDIO_U16LSB	0x0010  /* Unsigned 16-bit samples */
    64 #define AUDIO_S16LSB	0x8010	/* Signed 16-bit samples */
    71 #define AUDIO_S16LSB	0x8010  /* Signed 16-bit samples */
    65 #define AUDIO_U16MSB	0x1010	/* As above, but big-endian byte order */
    72 #define AUDIO_U16MSB	0x1010  /* As above, but big-endian byte order */
    66 #define AUDIO_S16MSB	0x9010	/* As above, but big-endian byte order */
    73 #define AUDIO_S16MSB	0x9010  /* As above, but big-endian byte order */
    67 #define AUDIO_U16	AUDIO_U16LSB
    74 #define AUDIO_U16	AUDIO_U16LSB
    68 #define AUDIO_S16	AUDIO_S16LSB
    75 #define AUDIO_S16	AUDIO_S16LSB
    69 
    76 
    70 /* Native audio byte ordering */
    77 /* Native audio byte ordering */
    71 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
    78 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
    76 #define AUDIO_S16SYS	AUDIO_S16MSB
    83 #define AUDIO_S16SYS	AUDIO_S16MSB
    77 #endif
    84 #endif
    78 
    85 
    79 
    86 
    80 /* A structure to hold a set of audio conversion filters and buffers */
    87 /* A structure to hold a set of audio conversion filters and buffers */
    81 typedef struct SDL_AudioCVT {
    88 typedef struct SDL_AudioCVT
    82 	int needed;			/* Set to 1 if conversion possible */
    89 {
    83 	Uint16 src_format;		/* Source audio format */
    90     int needed;                 /* Set to 1 if conversion possible */
    84 	Uint16 dst_format;		/* Target audio format */
    91     Uint16 src_format;          /* Source audio format */
    85 	double rate_incr;		/* Rate conversion increment */
    92     Uint16 dst_format;          /* Target audio format */
    86 	Uint8 *buf;			/* Buffer to hold entire audio data */
    93     double rate_incr;           /* Rate conversion increment */
    87 	int    len;			/* Length of original audio buffer */
    94     Uint8 *buf;                 /* Buffer to hold entire audio data */
    88 	int    len_cvt;			/* Length of converted audio buffer */
    95     int len;                    /* Length of original audio buffer */
    89 	int    len_mult;		/* buffer must be len*len_mult big */
    96     int len_cvt;                /* Length of converted audio buffer */
    90 	double len_ratio; 	/* Given len, final size is len*len_ratio */
    97     int len_mult;               /* buffer must be len*len_mult big */
    91 	void (SDLCALL *filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);
    98     double len_ratio;           /* Given len, final size is len*len_ratio */
    92 	int filter_index;		/* Current audio conversion function */
    99     void (SDLCALL * filters[10]) (struct SDL_AudioCVT * cvt, Uint16 format);
       
   100     int filter_index;           /* Current audio conversion function */
    93 } SDL_AudioCVT;
   101 } SDL_AudioCVT;
    94 
   102 
    95 
   103 
    96 /* Function prototypes */
   104 /* Function prototypes */
       
   105 
       
   106 /* These functions return the list of built in video drivers, in the 
       
   107  * order that they are normally initialized by default.
       
   108  */
       
   109 extern DECLSPEC int SDLCALL SDL_GetNumAudioDrivers(void);
       
   110 extern DECLSPEC const char *SDLCALL SDL_GetAudioDriver(int index);
    97 
   111 
    98 /* These functions are used internally, and should not be used unless you
   112 /* These functions are used internally, and should not be used unless you
    99  * have a specific need to specify the audio driver you want to use.
   113  * have a specific need to specify the audio driver you want to use.
   100  * You should normally use SDL_Init() or SDL_InitSubSystem().
   114  * You should normally use SDL_Init() or SDL_InitSubSystem().
   101  */
   115  */
   102 extern DECLSPEC int SDLCALL SDL_AudioInit(const char *driver_name);
   116 extern DECLSPEC int SDLCALL SDL_AudioInit(const char *driver_name);
   103 extern DECLSPEC void SDLCALL SDL_AudioQuit(void);
   117 extern DECLSPEC void SDLCALL SDL_AudioQuit(void);
   104 
   118 
   105 /* This function fills the given character buffer with the name of the
   119 /* This function returns the name of the current audio driver, or NULL
   106  * current audio driver, and returns a pointer to it if the audio driver has
   120  * if no driver has been initialized.
   107  * been initialized.  It returns NULL if no driver has been initialized.
   121  */
   108  */
   122 extern DECLSPEC const char *SDLCALL SDL_GetCurrentAudioDriver(void);
   109 extern DECLSPEC char * SDLCALL SDL_AudioDriverName(char *namebuf, int maxlen);
       
   110 
   123 
   111 /*
   124 /*
   112  * This function opens the audio device with the desired parameters, and
   125  * This function opens the audio device with the desired parameters, and
   113  * returns 0 if successful, placing the actual hardware parameters in the
   126  * returns 0 if successful, placing the actual hardware parameters in the
   114  * structure pointed to by 'obtained'.  If 'obtained' is NULL, the audio
   127  * structure pointed to by 'obtained'.  If 'obtained' is NULL, the audio
   147  * be enabled for playing by calling SDL_PauseAudio(0) when you are ready
   160  * be enabled for playing by calling SDL_PauseAudio(0) when you are ready
   148  * for your audio callback function to be called.  Since the audio driver
   161  * for your audio callback function to be called.  Since the audio driver
   149  * may modify the requested size of the audio buffer, you should allocate
   162  * may modify the requested size of the audio buffer, you should allocate
   150  * any local mixing buffers after you open the audio device.
   163  * any local mixing buffers after you open the audio device.
   151  */
   164  */
   152 extern DECLSPEC int SDLCALL SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained);
   165 extern DECLSPEC int SDLCALL SDL_OpenAudio(SDL_AudioSpec * desired,
       
   166                                           SDL_AudioSpec * obtained);
   153 
   167 
   154 /*
   168 /*
   155  * Get the current audio state:
   169  * Get the current audio state:
   156  */
   170  */
   157 typedef enum {
   171 typedef enum
   158 	SDL_AUDIO_STOPPED = 0,
   172 {
   159 	SDL_AUDIO_PLAYING,
   173     SDL_AUDIO_STOPPED = 0,
   160 	SDL_AUDIO_PAUSED
   174     SDL_AUDIO_PLAYING,
       
   175     SDL_AUDIO_PAUSED
   161 } SDL_audiostatus;
   176 } SDL_audiostatus;
   162 extern DECLSPEC SDL_audiostatus SDLCALL SDL_GetAudioStatus(void);
   177 extern DECLSPEC SDL_audiostatus SDLCALL SDL_GetAudioStatus(void);
   163 
   178 
   164 /*
   179 /*
   165  * This function pauses and unpauses the audio callback processing.
   180  * This function pauses and unpauses the audio callback processing.
   185  *
   200  *
   186  * This function returns NULL and sets the SDL error message if the 
   201  * This function returns NULL and sets the SDL error message if the 
   187  * wave file cannot be opened, uses an unknown data format, or is 
   202  * wave file cannot be opened, uses an unknown data format, or is 
   188  * corrupt.  Currently raw and MS-ADPCM WAVE files are supported.
   203  * corrupt.  Currently raw and MS-ADPCM WAVE files are supported.
   189  */
   204  */
   190 extern DECLSPEC SDL_AudioSpec * SDLCALL SDL_LoadWAV_RW(SDL_RWops *src, int freesrc, SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len);
   205 extern DECLSPEC SDL_AudioSpec *SDLCALL SDL_LoadWAV_RW(SDL_RWops * src,
       
   206                                                       int freesrc,
       
   207                                                       SDL_AudioSpec * spec,
       
   208                                                       Uint8 ** audio_buf,
       
   209                                                       Uint32 * audio_len);
   191 
   210 
   192 /* Compatibility convenience function -- loads a WAV from a file */
   211 /* Compatibility convenience function -- loads a WAV from a file */
   193 #define SDL_LoadWAV(file, spec, audio_buf, audio_len) \
   212 #define SDL_LoadWAV(file, spec, audio_buf, audio_len) \
   194 	SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
   213 	SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
   195 
   214 
   196 /*
   215 /*
   197  * This function frees data previously allocated with SDL_LoadWAV_RW()
   216  * This function frees data previously allocated with SDL_LoadWAV_RW()
   198  */
   217  */
   199 extern DECLSPEC void SDLCALL SDL_FreeWAV(Uint8 *audio_buf);
   218 extern DECLSPEC void SDLCALL SDL_FreeWAV(Uint8 * audio_buf);
   200 
   219 
   201 /*
   220 /*
   202  * This function takes a source format and rate and a destination format
   221  * This function takes a source format and rate and a destination format
   203  * and rate, and initializes the 'cvt' structure with information needed
   222  * and rate, and initializes the 'cvt' structure with information needed
   204  * by SDL_ConvertAudio() to convert a buffer of audio data from one format
   223  * by SDL_ConvertAudio() to convert a buffer of audio data from one format
   205  * to the other.
   224  * to the other.
   206  * This function returns 0, or -1 if there was an error.
   225  * This function returns 0, or -1 if there was an error.
   207  */
   226  */
   208 extern DECLSPEC int SDLCALL SDL_BuildAudioCVT(SDL_AudioCVT *cvt,
   227 extern DECLSPEC int SDLCALL SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
   209 		Uint16 src_format, Uint8 src_channels, int src_rate,
   228                                               Uint16 src_format,
   210 		Uint16 dst_format, Uint8 dst_channels, int dst_rate);
   229                                               Uint8 src_channels,
       
   230                                               int src_rate,
       
   231                                               Uint16 dst_format,
       
   232                                               Uint8 dst_channels,
       
   233                                               int dst_rate);
   211 
   234 
   212 /* Once you have initialized the 'cvt' structure using SDL_BuildAudioCVT(),
   235 /* Once you have initialized the 'cvt' structure using SDL_BuildAudioCVT(),
   213  * created an audio buffer cvt->buf, and filled it with cvt->len bytes of
   236  * created an audio buffer cvt->buf, and filled it with cvt->len bytes of
   214  * audio data in the source format, this function will convert it in-place
   237  * audio data in the source format, this function will convert it in-place
   215  * to the desired format.
   238  * to the desired format.
   216  * The data conversion may expand the size of the audio data, so the buffer
   239  * The data conversion may expand the size of the audio data, so the buffer
   217  * cvt->buf should be allocated after the cvt structure is initialized by
   240  * cvt->buf should be allocated after the cvt structure is initialized by
   218  * SDL_BuildAudioCVT(), and should be cvt->len*cvt->len_mult bytes long.
   241  * SDL_BuildAudioCVT(), and should be cvt->len*cvt->len_mult bytes long.
   219  */
   242  */
   220 extern DECLSPEC int SDLCALL SDL_ConvertAudio(SDL_AudioCVT *cvt);
   243 extern DECLSPEC int SDLCALL SDL_ConvertAudio(SDL_AudioCVT * cvt);
   221 
   244 
   222 /*
   245 /*
   223  * This takes two audio buffers of the playing audio format and mixes
   246  * This takes two audio buffers of the playing audio format and mixes
   224  * them, performing addition, volume adjustment, and overflow clipping.
   247  * them, performing addition, volume adjustment, and overflow clipping.
   225  * The volume ranges from 0 - 128, and should be set to SDL_MIX_MAXVOLUME
   248  * The volume ranges from 0 - 128, and should be set to SDL_MIX_MAXVOLUME
   226  * for full audio volume.  Note this does not change hardware volume.
   249  * for full audio volume.  Note this does not change hardware volume.
   227  * This is provided for convenience -- you can mix your own audio data.
   250  * This is provided for convenience -- you can mix your own audio data.
   228  */
   251  */
   229 #define SDL_MIX_MAXVOLUME 128
   252 #define SDL_MIX_MAXVOLUME 128
   230 extern DECLSPEC void SDLCALL SDL_MixAudio(Uint8 *dst, const Uint8 *src, Uint32 len, int volume);
   253 extern DECLSPEC void SDLCALL SDL_MixAudio(Uint8 * dst, const Uint8 * src,
       
   254                                           Uint32 len, int volume);
   231 
   255 
   232 /*
   256 /*
   233  * The lock manipulated by these functions protects the callback function.
   257  * The lock manipulated by these functions protects the callback function.
   234  * During a LockAudio/UnlockAudio pair, you can be guaranteed that the
   258  * During a LockAudio/UnlockAudio pair, you can be guaranteed that the
   235  * callback function is not running.  Do not call these from the callback
   259  * callback function is not running.  Do not call these from the callback
   244 extern DECLSPEC void SDLCALL SDL_CloseAudio(void);
   268 extern DECLSPEC void SDLCALL SDL_CloseAudio(void);
   245 
   269 
   246 
   270 
   247 /* Ends C function definitions when using C++ */
   271 /* Ends C function definitions when using C++ */
   248 #ifdef __cplusplus
   272 #ifdef __cplusplus
       
   273 /* *INDENT-OFF* */
   249 }
   274 }
       
   275 /* *INDENT-ON* */
   250 #endif
   276 #endif
   251 #include "close_code.h"
   277 #include "close_code.h"
   252 
   278 
   253 #endif /* _SDL_audio_h */
   279 #endif /* _SDL_audio_h */
       
   280 
       
   281 /* vi: set ts=4 sw=4 expandtab: */