Search
lxdream.org :: lxdream/src/aica/audio.h
lxdream 0.9.1
released Jun 29
Download Now
filename src/aica/audio.h
changeset 111:230243c2b520
prev106:9048bac046c3
next434:8af49a412d92
author nkeynes
date Thu Mar 16 12:41:59 2006 +0000 (15 years ago)
permissions -rw-r--r--
last change Handle driver-unable-to-init case
view annotate diff log raw
     1 /**
     2  * $Id: audio.h,v 1.7 2006-03-16 12:41:59 nkeynes Exp $
     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 <glib/gtypes.h>
    24 #ifdef __cplusplus
    25 extern "C" {
    26 #endif
    28 #define AUDIO_FMT_8BIT 0
    29 #define AUDIO_FMT_16BIT 1
    30 #define AUDIO_FMT_ADPCM 2
    31 #define AUDIO_FMT_MONO 0
    32 #define AUDIO_FMT_STEREO 4
    33 #define AUDIO_FMT_SIGNED 0
    34 #define AUDIO_FMT_UNSIGNED 8
    36 #define AUDIO_FMT_16ST (AUDIO_FMT_16BIT|AUDIO_FMT_STEREO)
    38 typedef struct audio_channel {
    39     gboolean active;
    40     uint32_t posn;
    41     uint32_t posn_left;
    42     uint32_t start;
    43     uint32_t end;
    44     gboolean loop;
    45     uint32_t loop_start;
    46     int vol; /* 0..255 */
    47     int pan; /* 0 (left) .. 31 (right) */
    48     uint32_t sample_rate;
    49     int sample_format; 
    50     /* Envelope etc stuff */
    51     /* ADPCM */
    52     int adpcm_nibble; /* 0 = low nibble, 1 = high nibble */
    53     int adpcm_step;
    54     int adpcm_predict;
    55 } *audio_channel_t;
    58 typedef struct audio_buffer {
    59     uint32_t length; /* Bytes */
    60     uint32_t posn; /* Bytes */
    61     int status;
    62     char data[0];
    63 } *audio_buffer_t;
    65 typedef struct audio_driver {
    66     char *name;
    67     gboolean (*set_output_format)( uint32_t sample_rate, uint32_t format );
    68     gboolean (*process_buffer)( audio_buffer_t buffer );
    69 } *audio_driver_t;
    71 extern struct audio_driver audio_null_driver;
    72 extern struct audio_driver audio_esd_driver;
    74 /**
    75  * Set the output driver, sample rate and format. Also initializes the 
    76  * output buffers, flushing any current data and reallocating as 
    77  * necessary. Must be called before attempting to generate any audio.
    78  */
    79 gboolean audio_set_driver( audio_driver_t driver, uint32_t samplerate,
    80 		       int format );
    82 /**
    83  * Mark the current write buffer as full and prepare the next buffer for
    84  * writing. Returns the next buffer to write to.
    85  * If all buffers are full, returns NULL.
    86  */
    87 audio_buffer_t audio_next_write_buffer();
    89 /**
    90  * Mark the current read buffer as empty and return the next buffer for
    91  * reading. If there is no next buffer yet, returns NULL.
    92  */
    93 audio_buffer_t audio_next_read_buffer();
    95 /**
    96  * Mix a single output sample and append it to the output buffers
    97  */
    98 void audio_mix_samples( int num_samples );
   100 /**
   101  * Retrieve the channel information for the channel, numbered 0..63. 
   102  */
   103 audio_channel_t audio_get_channel( int channel );
   105 void audio_start_channel( int channel );
   106 void audio_stop_channel( int channel );
   109 #ifdef __cplusplus
   110 }
   111 #endif
   112 #endif
.