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lxdream.org :: lxdream/src/aica/audio.h
lxdream 0.9.1
released Jun 29
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filename src/aica/audio.h
changeset 1024:c67f2d61ab97
prev759:f16975739abc
next1089:a3984d242909
author nkeynes
date Sat Jun 13 00:50:48 2009 +0000 (13 years ago)
permissions -rw-r--r--
last change Build drivers with library dependencies as shared objects (ie plugins)
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     1 /**
     2  * $Id$
     3  * 
     4  * Audio engine, ie the part that does the actual work.
     5  *
     6  * Copyright (c) 2005 Nathan Keynes.
     7  *
     8  * This program is free software; you can redistribute it and/or modify
     9  * it under the terms of the GNU General Public License as published by
    10  * the Free Software Foundation; either version 2 of the License, or
    11  * (at your option) any later version.
    12  *
    13  * This program is distributed in the hope that it will be useful,
    14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    16  * GNU General Public License for more details.
    17  */
    18 #ifndef lxdream_audio_H
    19 #define lxdream_audio_H 1
    21 #include <stdint.h>
    22 #include <stdio.h>
    23 #include <glib/gtypes.h>
    24 #include "gettext.h"
    25 #include "plugin.h"
    27 #ifdef __cplusplus
    28 extern "C" {
    29 #endif
    31 #define AUDIO_CHANNEL_COUNT 64
    33 #define AUDIO_FMT_8BIT 0
    34 #define AUDIO_FMT_16BIT 1
    35 #define AUDIO_FMT_ADPCM 2
    36 #define AUDIO_FMT_FLOAT 3  // 32-bit -1.0 to 1.0
    37 #define AUDIO_FMT_MONO 0
    38 #define AUDIO_FMT_STEREO 4
    39 #define AUDIO_FMT_SIGNED 0
    40 #define AUDIO_FMT_UNSIGNED 8
    42 #define AUDIO_FMT_SAMPLE_MASK 3
    44 #define AUDIO_FMT_16ST (AUDIO_FMT_16BIT|AUDIO_FMT_STEREO)
    45 #define AUDIO_FMT_FLOATST (AUDIO_FMT_FLOAT|AUDIO_FMT_STEREO)
    47 #define DEFAULT_SAMPLE_RATE 44100
    48 #define DEFAULT_SAMPLE_FORMAT AUDIO_FMT_16ST
    50 typedef enum { LOOP_OFF = 0, LOOP_ON = 1, LOOP_LOOPED = 2 } loop_t;
    52 typedef struct audio_channel {
    53     gboolean active;
    54     uint32_t posn; /* current sample #, 0 = first sample */
    55     uint32_t posn_left;
    56     uint32_t start;
    57     uint32_t end;
    58     loop_t loop;
    59     uint32_t loop_start;
    60     int vol; /* 0..255 */
    61     int pan; /* 0 (left) .. 31 (right) */
    62     uint32_t sample_rate;
    63     int sample_format; 
    64     /* Envelope etc stuff */
    65     /* ADPCM */
    66     int adpcm_step;
    67     int adpcm_predict;
    68 } *audio_channel_t;
    71 typedef struct audio_buffer {
    72     uint32_t length; /* Bytes */
    73     uint32_t posn; /* Bytes */
    74     int status;
    75     char data[0];
    76 } *audio_buffer_t;
    78 typedef struct audio_driver {
    79     const char *name;
    80     const char *description;
    81     int priority; /* Lower == higher priority */
    82     uint32_t sample_rate;
    83     uint32_t sample_format;
    84     gboolean (*init)( );
    85     void (*start)( );
    86     gboolean (*process_buffer)( audio_buffer_t buffer );
    87     void (*stop)( );
    88     gboolean (*shutdown)(  );
    89 } *audio_driver_t;
    92 /**
    93  * Print the configured audio drivers to the output stream, one to a line.
    94  */
    95 void print_audio_drivers( FILE *out );
    97 audio_driver_t get_audio_driver_by_name( const char *name );
    99 /**
   100  * Set the output driver, sample rate and format. Also initializes the 
   101  * output buffers, flushing any current data and reallocating as 
   102  * necessary. Must be called before attempting to generate any audio.
   103  */
   104 gboolean audio_set_driver( audio_driver_t driver );
   106 /**
   107  * Initialize the audio driver, using the specified driver if available.
   108  */
   109 audio_driver_t audio_init_driver( const char *preferred_driver );
   111 /**
   112  * Add a new audio driver to the available drivers list
   113  */
   114 gboolean audio_register_driver( audio_driver_t driver );
   116 /**
   117  * Signal the audio driver that playback is beginning
   118  */
   119 void audio_start_driver();
   121 /**
   122  * Signal the audio driver that playback is stopping
   123  */
   124 void audio_stop_driver();
   126 /**
   127  * Mark the current write buffer as full and prepare the next buffer for
   128  * writing. Returns the next buffer to write to.
   129  * If all buffers are full, returns NULL.
   130  */
   131 audio_buffer_t audio_next_write_buffer();
   133 /**
   134  * Mark the current read buffer as empty and return the next buffer for
   135  * reading. If there is no next buffer yet, returns NULL.
   136  */
   137 audio_buffer_t audio_next_read_buffer();
   139 /**
   140  * Mix a single output sample and append it to the output buffers
   141  */
   142 void audio_mix_samples( int num_samples );
   144 /**
   145  * Retrieve the channel information for the channel, numbered 0..63. 
   146  */
   147 audio_channel_t audio_get_channel( int channel );
   149 void audio_start_stop_channel( int channel, gboolean start );
   150 void audio_start_channel( int channel );
   151 void audio_stop_channel( int channel );
   153 void audio_save_state( FILE *f );
   154 int audio_load_state( FILE *f );
   156 #ifdef __cplusplus
   157 }
   158 #endif
   160 #endif /* !lxdream_audio_H */
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