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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 91:61bb3ee00cf8
prev82:81a4acf75f10
next106:9048bac046c3
author nkeynes
date Sun Feb 05 04:01:55 2006 +0000 (16 years ago)
permissions -rw-r--r--
last change Canonicalize typedef struct definition
file annotate diff log raw
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/**
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 * $Id: audio.h,v 1.5 2006-02-05 04:01:55 nkeynes Exp $
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 * 
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 * Audio engine, ie the part that does the actual work.
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 *
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 * Copyright (c) 2005 Nathan Keynes.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 */
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#ifndef dream_audio_H
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#define dream_audio_H 1
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#include <stdint.h>
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#include <glib/gtypes.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define AUDIO_FMT_8BIT 0
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#define AUDIO_FMT_16BIT 1
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#define AUDIO_FMT_ADPCM 2
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#define AUDIO_FMT_MONO 0
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#define AUDIO_FMT_STEREO 4
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#define AUDIO_FMT_SIGNED 0
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#define AUDIO_FMT_UNSIGNED 8
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typedef struct audio_channel {
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    gboolean active;
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    uint32_t posn;
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    uint32_t posn_left;
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    uint32_t start;
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    uint32_t end;
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    gboolean loop;
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    uint32_t loop_start;
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    int vol; /* 0..255 */
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    int pan; /* 0 (left) .. 31 (right) */
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    uint32_t sample_rate;
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    int sample_format; 
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    /* Envelope etc stuff */
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    /* ADPCM */
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    int adpcm_nibble; /* 0 = low nibble, 1 = high nibble */
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    int adpcm_step;
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    int adpcm_predict;
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} *audio_channel_t;
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typedef struct audio_buffer {
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    uint32_t length; /* Bytes */
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    uint32_t posn; /* Bytes */
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    int status;
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    char data[0];
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} *audio_buffer_t;
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typedef struct audio_driver {
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    char *name;
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    gboolean (*set_output_format)( uint32_t sample_rate, uint32_t format );
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    gboolean (*process_buffer)( audio_buffer_t buffer );
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} *audio_driver_t;
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extern struct audio_driver null_audio_driver;
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extern struct audio_driver esd_audio_driver;
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/**
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 * Set the output driver, sample rate and format. Also initializes the 
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 * output buffers, flushing any current data and reallocating as 
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 * necessary. Must be called before attempting to generate any audio.
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 */
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void audio_set_output( audio_driver_t driver, uint32_t samplerate,
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		       int format );
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/**
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 * Mark the current write buffer as full and prepare the next buffer for
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 * writing. Returns the next buffer to write to.
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 * If all buffers are full, returns NULL.
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 */
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audio_buffer_t audio_next_write_buffer();
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/**
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 * Mark the current read buffer as empty and return the next buffer for
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 * reading. If there is no next buffer yet, returns NULL.
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 */
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audio_buffer_t audio_next_read_buffer();
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/**
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 * Mix a single output sample and append it to the output buffers
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 */
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void audio_mix_samples( int num_samples );
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/**
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 * Retrieve the channel information for the channel, numbered 0..63. 
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 */
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audio_channel_t audio_get_channel( int channel );
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void audio_start_channel( int channel );
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void audio_stop_channel( int channel );
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#ifdef __cplusplus
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}
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#endif
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#endif
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