nkeynes@66: /**
nkeynes@463:  * $Id: audio.h,v 1.9 2007-10-24 21:24:09 nkeynes Exp $
nkeynes@66:  * 
nkeynes@66:  * Audio engine, ie the part that does the actual work.
nkeynes@66:  *
nkeynes@66:  * Copyright (c) 2005 Nathan Keynes.
nkeynes@66:  *
nkeynes@66:  * This program is free software; you can redistribute it and/or modify
nkeynes@66:  * it under the terms of the GNU General Public License as published by
nkeynes@66:  * the Free Software Foundation; either version 2 of the License, or
nkeynes@66:  * (at your option) any later version.
nkeynes@66:  *
nkeynes@66:  * This program is distributed in the hope that it will be useful,
nkeynes@66:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nkeynes@66:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nkeynes@66:  * GNU General Public License for more details.
nkeynes@66:  */
nkeynes@66: #ifndef dream_audio_H
nkeynes@66: #define dream_audio_H 1
nkeynes@66: 
nkeynes@66: #include <stdint.h>
nkeynes@66: #include <glib/gtypes.h>
nkeynes@66: 
nkeynes@66: #ifdef __cplusplus
nkeynes@66: extern "C" {
nkeynes@66: #endif
nkeynes@66: 
nkeynes@66: #define AUDIO_FMT_8BIT 0
nkeynes@66: #define AUDIO_FMT_16BIT 1
nkeynes@66: #define AUDIO_FMT_ADPCM 2
nkeynes@66: #define AUDIO_FMT_MONO 0
nkeynes@66: #define AUDIO_FMT_STEREO 4
nkeynes@66: #define AUDIO_FMT_SIGNED 0
nkeynes@66: #define AUDIO_FMT_UNSIGNED 8
nkeynes@66: 
nkeynes@106: #define AUDIO_FMT_16ST (AUDIO_FMT_16BIT|AUDIO_FMT_STEREO)
nkeynes@66: 
nkeynes@463: typedef enum { LOOP_OFF = 0, LOOP_ON = 1, LOOP_LOOPED = 2 } loop_t;
nkeynes@463: 
nkeynes@66: typedef struct audio_channel {
nkeynes@66:     gboolean active;
nkeynes@434:     uint32_t posn; /* current sample #, 0 = first sample */
nkeynes@66:     uint32_t posn_left;
nkeynes@66:     uint32_t start;
nkeynes@66:     uint32_t end;
nkeynes@463:     loop_t loop;
nkeynes@66:     uint32_t loop_start;
nkeynes@82:     int vol; /* 0..255 */
nkeynes@82:     int pan; /* 0 (left) .. 31 (right) */
nkeynes@66:     uint32_t sample_rate;
nkeynes@66:     int sample_format; 
nkeynes@66:     /* Envelope etc stuff */
nkeynes@66:     /* ADPCM */
nkeynes@66:     int adpcm_step;
nkeynes@66:     int adpcm_predict;
nkeynes@66: } *audio_channel_t;
nkeynes@66: 
nkeynes@66: 
nkeynes@66: typedef struct audio_buffer {
nkeynes@73:     uint32_t length; /* Bytes */
nkeynes@73:     uint32_t posn; /* Bytes */
nkeynes@66:     int status;
nkeynes@66:     char data[0];
nkeynes@66: } *audio_buffer_t;
nkeynes@66: 
nkeynes@91: typedef struct audio_driver {
nkeynes@74:     char *name;
nkeynes@66:     gboolean (*set_output_format)( uint32_t sample_rate, uint32_t format );
nkeynes@66:     gboolean (*process_buffer)( audio_buffer_t buffer );
nkeynes@91: } *audio_driver_t;
nkeynes@66: 
nkeynes@106: extern struct audio_driver audio_null_driver;
nkeynes@106: extern struct audio_driver audio_esd_driver;
nkeynes@66: 
nkeynes@66: /**
nkeynes@66:  * Set the output driver, sample rate and format. Also initializes the 
nkeynes@66:  * output buffers, flushing any current data and reallocating as 
nkeynes@66:  * necessary. Must be called before attempting to generate any audio.
nkeynes@66:  */
nkeynes@111: gboolean audio_set_driver( audio_driver_t driver, uint32_t samplerate,
nkeynes@66: 		       int format );
nkeynes@66: 
nkeynes@66: /**
nkeynes@66:  * Mark the current write buffer as full and prepare the next buffer for
nkeynes@66:  * writing. Returns the next buffer to write to.
nkeynes@66:  * If all buffers are full, returns NULL.
nkeynes@66:  */
nkeynes@66: audio_buffer_t audio_next_write_buffer();
nkeynes@66: 
nkeynes@66: /**
nkeynes@66:  * Mark the current read buffer as empty and return the next buffer for
nkeynes@66:  * reading. If there is no next buffer yet, returns NULL.
nkeynes@66:  */
nkeynes@66: audio_buffer_t audio_next_read_buffer();
nkeynes@66: 
nkeynes@66: /**
nkeynes@66:  * Mix a single output sample and append it to the output buffers
nkeynes@66:  */
nkeynes@73: void audio_mix_samples( int num_samples );
nkeynes@66: 
nkeynes@66: /**
nkeynes@66:  * Retrieve the channel information for the channel, numbered 0..63. 
nkeynes@66:  */
nkeynes@66: audio_channel_t audio_get_channel( int channel );
nkeynes@66: 
nkeynes@434: void audio_start_stop_channel( int channel, gboolean start );
nkeynes@66: void audio_start_channel( int channel );
nkeynes@66: void audio_stop_channel( int channel );
nkeynes@66: 
nkeynes@66: 
nkeynes@66: #ifdef __cplusplus
nkeynes@66: }
nkeynes@66: #endif
nkeynes@66: #endif