1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/include/SDL_audio.h Thu Apr 26 16:45:43 2001 +0000
1.3 @@ -0,0 +1,260 @@
1.4 +/*
1.5 + SDL - Simple DirectMedia Layer
1.6 + Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
1.7 +
1.8 + This library is free software; you can redistribute it and/or
1.9 + modify it under the terms of the GNU Library General Public
1.10 + License as published by the Free Software Foundation; either
1.11 + version 2 of the License, or (at your option) any later version.
1.12 +
1.13 + This library is distributed in the hope that it will be useful,
1.14 + but WITHOUT ANY WARRANTY; without even the implied warranty of
1.15 + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1.16 + Library General Public License for more details.
1.17 +
1.18 + You should have received a copy of the GNU Library General Public
1.19 + License along with this library; if not, write to the Free
1.20 + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
1.21 +
1.22 + Sam Lantinga
1.23 + slouken@devolution.com
1.24 +*/
1.25 +
1.26 +#ifdef SAVE_RCSID
1.27 +static char rcsid =
1.28 + "@(#) $Id$";
1.29 +#endif
1.30 +
1.31 +/* Access to the raw audio mixing buffer for the SDL library */
1.32 +
1.33 +#ifndef _SDL_audio_h
1.34 +#define _SDL_audio_h
1.35 +
1.36 +#include <stdio.h>
1.37 +
1.38 +#include "SDL_main.h"
1.39 +#include "SDL_types.h"
1.40 +#include "SDL_error.h"
1.41 +#include "SDL_rwops.h"
1.42 +#include "SDL_byteorder.h"
1.43 +
1.44 +#include "begin_code.h"
1.45 +/* Set up for C function definitions, even when using C++ */
1.46 +#ifdef __cplusplus
1.47 +extern "C" {
1.48 +#endif
1.49 +
1.50 +/* The calculated values in this structure are calculated by SDL_OpenAudio() */
1.51 +typedef struct {
1.52 + int freq; /* DSP frequency -- samples per second */
1.53 + Uint16 format; /* Audio data format */
1.54 + Uint8 channels; /* Number of channels: 1 mono, 2 stereo */
1.55 + Uint8 silence; /* Audio buffer silence value (calculated) */
1.56 + Uint16 samples; /* Audio buffer size in samples */
1.57 + Uint16 padding; /* Necessary for some compile environments */
1.58 + Uint32 size; /* Audio buffer size in bytes (calculated) */
1.59 + /* This function is called when the audio device needs more data.
1.60 + 'stream' is a pointer to the audio data buffer
1.61 + 'len' is the length of that buffer in bytes.
1.62 + Once the callback returns, the buffer will no longer be valid.
1.63 + Stereo samples are stored in a LRLRLR ordering.
1.64 + */
1.65 + void (*callback)(void *userdata, Uint8 *stream, int len);
1.66 + void *userdata;
1.67 +} SDL_AudioSpec;
1.68 +
1.69 +/* Audio format flags (defaults to LSB byte order) */
1.70 +#define AUDIO_U8 0x0008 /* Unsigned 8-bit samples */
1.71 +#define AUDIO_S8 0x8008 /* Signed 8-bit samples */
1.72 +#define AUDIO_U16LSB 0x0010 /* Unsigned 16-bit samples */
1.73 +#define AUDIO_S16LSB 0x8010 /* Signed 16-bit samples */
1.74 +#define AUDIO_U16MSB 0x1010 /* As above, but big-endian byte order */
1.75 +#define AUDIO_S16MSB 0x9010 /* As above, but big-endian byte order */
1.76 +#define AUDIO_U16 AUDIO_U16LSB
1.77 +#define AUDIO_S16 AUDIO_S16LSB
1.78 +
1.79 +/* Native audio byte ordering */
1.80 +#if SDL_BYTEORDER == SDL_LIL_ENDIAN
1.81 +#define AUDIO_U16SYS AUDIO_U16LSB
1.82 +#define AUDIO_S16SYS AUDIO_S16LSB
1.83 +#else
1.84 +#define AUDIO_U16SYS AUDIO_U16MSB
1.85 +#define AUDIO_S16SYS AUDIO_S16MSB
1.86 +#endif
1.87 +
1.88 +
1.89 +/* A structure to hold a set of audio conversion filters and buffers */
1.90 +typedef struct SDL_AudioCVT {
1.91 + int needed; /* Set to 1 if conversion possible */
1.92 + Uint16 src_format; /* Source audio format */
1.93 + Uint16 dst_format; /* Target audio format */
1.94 + double rate_incr; /* Rate conversion increment */
1.95 + Uint8 *buf; /* Buffer to hold entire audio data */
1.96 + int len; /* Length of original audio buffer */
1.97 + int len_cvt; /* Length of converted audio buffer */
1.98 + int len_mult; /* buffer must be len*len_mult big */
1.99 + double len_ratio; /* Given len, final size is len*len_ratio */
1.100 + void (*filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);
1.101 + int filter_index; /* Current audio conversion function */
1.102 +} SDL_AudioCVT;
1.103 +
1.104 +
1.105 +/* Function prototypes */
1.106 +
1.107 +/* These functions are used internally, and should not be used unless you
1.108 + * have a specific need to specify the audio driver you want to use.
1.109 + * You should normally use SDL_Init() or SDL_InitSubSystem().
1.110 + */
1.111 +extern DECLSPEC int SDL_AudioInit(const char *driver_name);
1.112 +extern DECLSPEC void SDL_AudioQuit(void);
1.113 +
1.114 +/* This function fills the given character buffer with the name of the
1.115 + * current audio driver, and returns a pointer to it if the audio driver has
1.116 + * been initialized. It returns NULL if no driver has been initialized.
1.117 + */
1.118 +extern DECLSPEC char *SDL_AudioDriverName(char *namebuf, int maxlen);
1.119 +
1.120 +/*
1.121 + * This function opens the audio device with the desired parameters, and
1.122 + * returns 0 if successful, placing the actual hardware parameters in the
1.123 + * structure pointed to by 'obtained'. If 'obtained' is NULL, the audio
1.124 + * data passed to the callback function will be guaranteed to be in the
1.125 + * requested format, and will be automatically converted to the hardware
1.126 + * audio format if necessary. This function returns -1 if it failed
1.127 + * to open the audio device, or couldn't set up the audio thread.
1.128 + *
1.129 + * When filling in the desired audio spec structure,
1.130 + * 'desired->freq' should be the desired audio frequency in samples-per-second.
1.131 + * 'desired->format' should be the desired audio format.
1.132 + * 'desired->samples' is the desired size of the audio buffer, in samples.
1.133 + * This number should be a power of two, and may be adjusted by the audio
1.134 + * driver to a value more suitable for the hardware. Good values seem to
1.135 + * range between 512 and 8096 inclusive, depending on the application and
1.136 + * CPU speed. Smaller values yield faster response time, but can lead
1.137 + * to underflow if the application is doing heavy processing and cannot
1.138 + * fill the audio buffer in time. A stereo sample consists of both right
1.139 + * and left channels in LR ordering.
1.140 + * Note that the number of samples is directly related to time by the
1.141 + * following formula: ms = (samples*1000)/freq
1.142 + * 'desired->size' is the size in bytes of the audio buffer, and is
1.143 + * calculated by SDL_OpenAudio().
1.144 + * 'desired->silence' is the value used to set the buffer to silence,
1.145 + * and is calculated by SDL_OpenAudio().
1.146 + * 'desired->callback' should be set to a function that will be called
1.147 + * when the audio device is ready for more data. It is passed a pointer
1.148 + * to the audio buffer, and the length in bytes of the audio buffer.
1.149 + * This function usually runs in a separate thread, and so you should
1.150 + * protect data structures that it accesses by calling SDL_LockAudio()
1.151 + * and SDL_UnlockAudio() in your code.
1.152 + * 'desired->userdata' is passed as the first parameter to your callback
1.153 + * function.
1.154 + *
1.155 + * The audio device starts out playing silence when it's opened, and should
1.156 + * be enabled for playing by calling SDL_PauseAudio(0) when you are ready
1.157 + * for your audio callback function to be called. Since the audio driver
1.158 + * may modify the requested size of the audio buffer, you should allocate
1.159 + * any local mixing buffers after you open the audio device.
1.160 + */
1.161 +extern DECLSPEC int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained);
1.162 +
1.163 +/*
1.164 + * Get the current audio state:
1.165 + */
1.166 +typedef enum {
1.167 + SDL_AUDIO_STOPPED = 0,
1.168 + SDL_AUDIO_PLAYING,
1.169 + SDL_AUDIO_PAUSED
1.170 +} SDL_audiostatus;
1.171 +extern DECLSPEC SDL_audiostatus SDL_GetAudioStatus(void);
1.172 +
1.173 +/*
1.174 + * This function pauses and unpauses the audio callback processing.
1.175 + * It should be called with a parameter of 0 after opening the audio
1.176 + * device to start playing sound. This is so you can safely initialize
1.177 + * data for your callback function after opening the audio device.
1.178 + * Silence will be written to the audio device during the pause.
1.179 + */
1.180 +extern DECLSPEC void SDL_PauseAudio(int pause_on);
1.181 +
1.182 +/*
1.183 + * This function loads a WAVE from the data source, automatically freeing
1.184 + * that source if 'freesrc' is non-zero. For example, to load a WAVE file,
1.185 + * you could do:
1.186 + * SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
1.187 + *
1.188 + * If this function succeeds, it returns the given SDL_AudioSpec,
1.189 + * filled with the audio data format of the wave data, and sets
1.190 + * 'audio_buf' to a malloc()'d buffer containing the audio data,
1.191 + * and sets 'audio_len' to the length of that audio buffer, in bytes.
1.192 + * You need to free the audio buffer with SDL_FreeWAV() when you are
1.193 + * done with it.
1.194 + *
1.195 + * This function returns NULL and sets the SDL error message if the
1.196 + * wave file cannot be opened, uses an unknown data format, or is
1.197 + * corrupt. Currently raw and MS-ADPCM WAVE files are supported.
1.198 + */
1.199 +extern DECLSPEC SDL_AudioSpec *SDL_LoadWAV_RW(SDL_RWops *src, int freesrc,
1.200 + SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len);
1.201 +
1.202 +/* Compatibility convenience function -- loads a WAV from a file */
1.203 +#define SDL_LoadWAV(file, spec, audio_buf, audio_len) \
1.204 + SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
1.205 +
1.206 +/*
1.207 + * This function frees data previously allocated with SDL_LoadWAV_RW()
1.208 + */
1.209 +extern DECLSPEC void SDL_FreeWAV(Uint8 *audio_buf);
1.210 +
1.211 +/*
1.212 + * This function takes a source format and rate and a destination format
1.213 + * and rate, and initializes the 'cvt' structure with information needed
1.214 + * by SDL_ConvertAudio() to convert a buffer of audio data from one format
1.215 + * to the other.
1.216 + * This function returns 0, or -1 if there was an error.
1.217 + */
1.218 +extern DECLSPEC int SDL_BuildAudioCVT(SDL_AudioCVT *cvt,
1.219 + Uint16 src_format, Uint8 src_channels, int src_rate,
1.220 + Uint16 dst_format, Uint8 dst_channels, int dst_rate);
1.221 +
1.222 +/* Once you have initialized the 'cvt' structure using SDL_BuildAudioCVT(),
1.223 + * created an audio buffer cvt->buf, and filled it with cvt->len bytes of
1.224 + * audio data in the source format, this function will convert it in-place
1.225 + * to the desired format.
1.226 + * The data conversion may expand the size of the audio data, so the buffer
1.227 + * cvt->buf should be allocated after the cvt structure is initialized by
1.228 + * SDL_BuildAudioCVT(), and should be cvt->len*cvt->len_mult bytes long.
1.229 + */
1.230 +extern DECLSPEC int SDL_ConvertAudio(SDL_AudioCVT *cvt);
1.231 +
1.232 +/*
1.233 + * This takes two audio buffers of the playing audio format and mixes
1.234 + * them, performing addition, volume adjustment, and overflow clipping.
1.235 + * The volume ranges from 0 - 128, and should be set to SDL_MIX_MAXVOLUME
1.236 + * for full audio volume. Note this does not change hardware volume.
1.237 + * This is provided for convenience -- you can mix your own audio data.
1.238 + */
1.239 +#define SDL_MIX_MAXVOLUME 128
1.240 +extern DECLSPEC void SDL_MixAudio(Uint8 *dst, Uint8 *src, Uint32 len, int volume);
1.241 +
1.242 +/*
1.243 + * The lock manipulated by these functions protects the callback function.
1.244 + * During a LockAudio/UnlockAudio pair, you can be guaranteed that the
1.245 + * callback function is not running. Do not call these from the callback
1.246 + * function or you will cause deadlock.
1.247 + */
1.248 +extern DECLSPEC void SDL_LockAudio(void);
1.249 +extern DECLSPEC void SDL_UnlockAudio(void);
1.250 +
1.251 +/*
1.252 + * This function shuts down audio processing and closes the audio device.
1.253 + */
1.254 +extern DECLSPEC void SDL_CloseAudio(void);
1.255 +
1.256 +
1.257 +/* Ends C function definitions when using C++ */
1.258 +#ifdef __cplusplus
1.259 +}
1.260 +#endif
1.261 +#include "close_code.h"
1.262 +
1.263 +#endif /* _SDL_audio_h */