lxdream 0.9.1| filename | src/aica/audio.h |
| changeset | 111:230243c2b520 |
| prev | 106:9048bac046c3 |
| next | 434:8af49a412d92 |
| author | nkeynes |
| date | Wed Jan 03 09:00:17 2007 +0000 (17 years ago) |
| permissions | -rw-r--r-- |
| last change | Adjust timers when they're read rather than waiting until the next time slice. Also temporarily cut the CPU time by 4. Initialize the FRQCR register to 0x0E0A for convenience |
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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
.