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SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 10 Jul 2006 21:04:37 +0000
parents c71e05b4dc2e
children 071b6598d48f
comparison
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: */