nkeynes@989 | 1 | /**
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nkeynes@989 | 2 | * $Id: audio_pulse.c 754 2008-07-14 07:44:42Z nkeynes $
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nkeynes@989 | 3 | *
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nkeynes@989 | 4 | * The SDL sound driver
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nkeynes@989 | 5 | *
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nkeynes@989 | 6 | * Copyright (c) 2009 wahrhaft
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nkeynes@989 | 7 | *
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nkeynes@989 | 8 | * This program is free software; you can redistribute it and/or modify
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nkeynes@989 | 9 | * it under the terms of the GNU General Public License as published by
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nkeynes@989 | 10 | * the Free Software Foundation; either version 2 of the License, or
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nkeynes@989 | 11 | * (at your option) any later version.
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nkeynes@989 | 12 | *
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nkeynes@989 | 13 | * This program is distributed in the hope that it will be useful,
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nkeynes@989 | 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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nkeynes@989 | 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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nkeynes@989 | 16 | * GNU General Public License for more details.
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nkeynes@989 | 17 | */
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nkeynes@989 | 18 | #include <stdio.h>
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nkeynes@989 | 19 | #include <unistd.h>
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nkeynes@989 | 20 | #include <SDL/SDL.h>
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nkeynes@989 | 21 | #include <SDL/SDL_audio.h>
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nkeynes@989 | 22 | #include "aica/audio.h"
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nkeynes@989 | 23 | #include "lxdream.h"
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nkeynes@989 | 24 |
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nkeynes@989 | 25 | #define SDL_SAMPLES 512 //tweaking this value may help with audio dropouts
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nkeynes@989 | 26 | #define BYTES_PER_SAMPLE 4 //should be changed if samples are not S16 stereo
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nkeynes@989 | 27 |
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nkeynes@989 | 28 | #define BUFFER_MIN_SIZE SDL_SAMPLES * BYTES_PER_SAMPLE * 4
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nkeynes@989 | 29 | #define BUFFER_MAX_SIZE SDL_SAMPLES * BYTES_PER_SAMPLE * 16
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nkeynes@989 | 30 |
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nkeynes@989 | 31 | char *audio_buffer;
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nkeynes@989 | 32 | int buffer_pos;
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nkeynes@989 | 33 |
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nkeynes@989 | 34 | void mix_audio(void *userdata, Uint8 *stream, int len);
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nkeynes@994 | 35 | void audio_sdl_start();
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nkeynes@989 | 36 |
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nkeynes@989 | 37 | gboolean audio_sdl_init( )
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nkeynes@989 | 38 | {
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nkeynes@989 | 39 | int rate = DEFAULT_SAMPLE_RATE;
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nkeynes@989 | 40 | int format = DEFAULT_SAMPLE_FORMAT;
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nkeynes@989 | 41 |
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nkeynes@989 | 42 | SDL_AudioSpec fmt;
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nkeynes@989 | 43 | fmt.freq = rate;
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nkeynes@989 | 44 | if (format & AUDIO_FMT_16BIT)
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nkeynes@989 | 45 | fmt.format = AUDIO_S16;
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nkeynes@989 | 46 | else
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nkeynes@989 | 47 | fmt.format = AUDIO_U8;
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nkeynes@989 | 48 | if (format & AUDIO_FMT_STEREO)
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nkeynes@989 | 49 | fmt.channels = 2;
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nkeynes@989 | 50 | else
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nkeynes@989 | 51 | fmt.channels = 1;
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nkeynes@989 | 52 |
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nkeynes@989 | 53 | fmt.samples = SDL_SAMPLES;
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nkeynes@989 | 54 | fmt.callback = mix_audio;
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nkeynes@989 | 55 | fmt.userdata = NULL;
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nkeynes@989 | 56 |
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nkeynes@989 | 57 | if (SDL_OpenAudio(&fmt, NULL) < 0)
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nkeynes@989 | 58 | {
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nkeynes@989 | 59 | ERROR("Unable to open audio output (SDL)");
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nkeynes@989 | 60 | return FALSE;
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nkeynes@989 | 61 | }
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nkeynes@989 | 62 | buffer_pos = 0;
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nkeynes@989 | 63 | audio_buffer = (char*)malloc(BUFFER_MAX_SIZE * sizeof(char));
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nkeynes@989 | 64 | if (audio_buffer == NULL)
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nkeynes@989 | 65 | {
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nkeynes@989 | 66 | ERROR("Could not allocate audio buffer (SDL)");
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nkeynes@989 | 67 | return FALSE;
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nkeynes@989 | 68 | }
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nkeynes@989 | 69 |
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nkeynes@989 | 70 | //hmm, this doesn't seem to get called externally...
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nkeynes@989 | 71 | audio_sdl_start();
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nkeynes@989 | 72 |
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nkeynes@989 | 73 | return TRUE;
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nkeynes@989 | 74 | }
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nkeynes@989 | 75 |
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nkeynes@989 | 76 | gboolean audio_sdl_process_buffer( audio_buffer_t buffer )
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nkeynes@989 | 77 | {
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nkeynes@989 | 78 | SDL_LockAudio();
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nkeynes@989 | 79 | if (buffer_pos + buffer->length >= BUFFER_MAX_SIZE)
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nkeynes@989 | 80 | {
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nkeynes@989 | 81 | printf("Audio buffer full, dropping a chunk\n");
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nkeynes@989 | 82 | }
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nkeynes@989 | 83 | else
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nkeynes@989 | 84 | {
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nkeynes@989 | 85 | memcpy(audio_buffer, buffer->data, buffer->length);
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nkeynes@989 | 86 | buffer_pos += buffer->length;
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nkeynes@989 | 87 | }
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nkeynes@989 | 88 | SDL_UnlockAudio();
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nkeynes@989 | 89 |
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nkeynes@989 | 90 | return TRUE;
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nkeynes@989 | 91 | }
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nkeynes@989 | 92 |
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nkeynes@989 | 93 | void mix_audio(void *userdata, Uint8 *stream, int len)
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nkeynes@989 | 94 | {
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nkeynes@989 | 95 | if (len < buffer_pos)
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nkeynes@989 | 96 | {
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nkeynes@989 | 97 | memcpy(stream, audio_buffer, len);
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nkeynes@989 | 98 | }
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nkeynes@989 | 99 | if (buffer_pos > BUFFER_MIN_SIZE)
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nkeynes@989 | 100 | {
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nkeynes@989 | 101 | memcpy(audio_buffer, &audio_buffer[len], buffer_pos - len);
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nkeynes@989 | 102 | buffer_pos -= len;
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nkeynes@989 | 103 | }
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nkeynes@989 | 104 | else
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nkeynes@989 | 105 | {
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nkeynes@989 | 106 | //printf("Audio buffer low, repeating a chunk\n");
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nkeynes@989 | 107 | }
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nkeynes@989 | 108 | }
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nkeynes@989 | 109 |
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nkeynes@989 | 110 | gboolean audio_sdl_shutdown()
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nkeynes@989 | 111 | {
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nkeynes@989 | 112 | SDL_CloseAudio();
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nkeynes@989 | 113 | free(audio_buffer);
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nkeynes@989 | 114 | return TRUE;
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nkeynes@989 | 115 | }
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nkeynes@989 | 116 |
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nkeynes@989 | 117 | void audio_sdl_start()
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nkeynes@989 | 118 | {
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nkeynes@989 | 119 | SDL_PauseAudio(0);
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nkeynes@989 | 120 | }
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nkeynes@989 | 121 |
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nkeynes@989 | 122 | void audio_sdl_stop()
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nkeynes@989 | 123 | {
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nkeynes@989 | 124 | SDL_PauseAudio(1);
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nkeynes@989 | 125 | }
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nkeynes@989 | 126 |
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nkeynes@989 | 127 | struct audio_driver audio_sdl_driver = {
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nkeynes@989 | 128 | "sdl",
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nkeynes@989 | 129 | N_("SDL sound driver"),
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nkeynes@989 | 130 | DEFAULT_SAMPLE_RATE,
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nkeynes@989 | 131 | DEFAULT_SAMPLE_FORMAT,
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nkeynes@989 | 132 | audio_sdl_init,
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nkeynes@989 | 133 | audio_sdl_start,
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nkeynes@989 | 134 | audio_sdl_process_buffer,
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nkeynes@989 | 135 | audio_sdl_stop,
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nkeynes@989 | 136 | audio_sdl_shutdown
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nkeynes@989 | 137 | };
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nkeynes@989 | 138 |
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