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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 697:479b8c213f61
prev657:c4143facbfcb
next700:4650d0c7f6f9
author nkeynes
date Sun Jun 22 04:01:27 2008 +0000 (13 years ago)
permissions -rw-r--r--
last change Commit work-in-progress CoreAudio driver
(along with various changes to the audio subsystem)
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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 dream_audio_H
    19 #define dream_audio_H 1
    21 #include <stdint.h>
    22 #include <stdio.h>
    23 #include <glib/gtypes.h>
    25 #ifdef __cplusplus
    26 extern "C" {
    27 #endif
    29 #define AUDIO_CHANNEL_COUNT 64
    31 #define AUDIO_FMT_8BIT 0
    32 #define AUDIO_FMT_16BIT 1
    33 #define AUDIO_FMT_ADPCM 2
    34 #define AUDIO_FMT_FLOAT 3  // 32-bit -1.0 to 1.0
    35 #define AUDIO_FMT_MONO 0
    36 #define AUDIO_FMT_STEREO 4
    37 #define AUDIO_FMT_SIGNED 0
    38 #define AUDIO_FMT_UNSIGNED 8
    40 #define AUDIO_FMT_SAMPLE_MASK 3
    42 #define AUDIO_FMT_16ST (AUDIO_FMT_16BIT|AUDIO_FMT_STEREO)
    43 #define AUDIO_FMT_FLOATST (AUDIO_FMT_FLOAT|AUDIO_FMT_STEREO)
    45 #define DEFAULT_SAMPLE_RATE 44100
    46 #define DEFAULT_SAMPLE_FORMAT AUDIO_FMT_16ST
    48 typedef enum { LOOP_OFF = 0, LOOP_ON = 1, LOOP_LOOPED = 2 } loop_t;
    50 typedef struct audio_channel {
    51     gboolean active;
    52     uint32_t posn; /* current sample #, 0 = first sample */
    53     uint32_t posn_left;
    54     uint32_t start;
    55     uint32_t end;
    56     loop_t loop;
    57     uint32_t loop_start;
    58     int vol; /* 0..255 */
    59     int pan; /* 0 (left) .. 31 (right) */
    60     uint32_t sample_rate;
    61     int sample_format; 
    62     /* Envelope etc stuff */
    63     /* ADPCM */
    64     int adpcm_step;
    65     int adpcm_predict;
    66 } *audio_channel_t;
    69 typedef struct audio_buffer {
    70     uint32_t length; /* Bytes */
    71     uint32_t posn; /* Bytes */
    72     int status;
    73     char data[0];
    74 } *audio_buffer_t;
    76 typedef struct audio_driver {
    77     char *name;
    78     uint32_t sample_rate;
    79     uint32_t sample_format;
    80     gboolean (*init)( );
    81     void (*start)( );
    82     gboolean (*process_buffer)( audio_buffer_t buffer );
    83     void (*stop)( );
    84     gboolean (*shutdown)(  );
    85 } *audio_driver_t;
    87 audio_driver_t get_audio_driver_by_name( const char *name );
    89 /**
    90  * Set the output driver, sample rate and format. Also initializes the 
    91  * output buffers, flushing any current data and reallocating as 
    92  * necessary. Must be called before attempting to generate any audio.
    93  */
    94 gboolean audio_set_driver( audio_driver_t driver );
    96 /**
    97  * Mark the current write buffer as full and prepare the next buffer for
    98  * writing. Returns the next buffer to write to.
    99  * If all buffers are full, returns NULL.
   100  */
   101 audio_buffer_t audio_next_write_buffer();
   103 /**
   104  * Mark the current read buffer as empty and return the next buffer for
   105  * reading. If there is no next buffer yet, returns NULL.
   106  */
   107 audio_buffer_t audio_next_read_buffer();
   109 /**
   110  * Mix a single output sample and append it to the output buffers
   111  */
   112 void audio_mix_samples( int num_samples );
   114 /**
   115  * Retrieve the channel information for the channel, numbered 0..63. 
   116  */
   117 audio_channel_t audio_get_channel( int channel );
   119 void audio_start_stop_channel( int channel, gboolean start );
   120 void audio_start_channel( int channel );
   121 void audio_stop_channel( int channel );
   123 void audio_save_state( FILE *f );
   124 int audio_load_state( FILE *f );
   126 #ifdef __cplusplus
   127 }
   128 #endif
   129 #endif
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