annotate src/audio/dsp/SDL_dspaudio.c @ 968:4675910b0b7b

Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 12 Nov 2004 21:39:04 +0000
parents eec28a5278be
children c5dedfdb4e42
rev   line source
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997-2004 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@libsdl.org
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21
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22 Modified in Oct 2004 by Hannu Savolainen
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23 hannu@opensound.com
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24 */
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25
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26 #ifdef SAVE_RCSID
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27 static char rcsid =
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28 "@(#) $Id$";
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29 #endif
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30
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31 /* Allow access to a raw mixing buffer */
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32
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33 #include <stdlib.h>
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34 #include <stdio.h>
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35 #include <string.h>
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36 #include <errno.h>
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37 #include <unistd.h>
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38 #include <fcntl.h>
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39 #include <signal.h>
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40 #include <sys/time.h>
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41 #include <sys/ioctl.h>
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42 #include <sys/stat.h>
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43 #ifdef OSS_USE_SOUNDCARD_H
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44 /* This is installed on some systems */
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45 #include <soundcard.h>
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46 #else
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47 /* This is recommended by OSS */
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48 #include <sys/soundcard.h>
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49 #endif
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50
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51 #include "SDL_audio.h"
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52 #include "SDL_error.h"
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53 #include "SDL_audiomem.h"
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54 #include "SDL_audio_c.h"
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55 #include "SDL_timer.h"
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56 #include "SDL_audiodev_c.h"
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57 #include "SDL_dspaudio.h"
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58
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59 /* The tag name used by DSP audio */
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60 #define DSP_DRIVER_NAME "dsp"
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61
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62 /* Open the audio device for playback, and don't block if busy */
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63 #define OPEN_FLAGS (O_WRONLY|O_NONBLOCK)
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64
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65 /* Audio driver functions */
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66 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec);
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67 static void DSP_WaitAudio(_THIS);
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68 static void DSP_PlayAudio(_THIS);
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69 static Uint8 *DSP_GetAudioBuf(_THIS);
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70 static void DSP_CloseAudio(_THIS);
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71
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72 /* Audio driver bootstrap functions */
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73
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74 static int Audio_Available(void)
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75 {
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76 int fd;
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77 int available;
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78
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79 available = 0;
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80 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
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81 if ( fd >= 0 ) {
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82 available = 1;
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83 close(fd);
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84 }
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85 return(available);
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86 }
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87
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88 static void Audio_DeleteDevice(SDL_AudioDevice *device)
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89 {
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90 free(device->hidden);
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91 free(device);
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92 }
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93
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94 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
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95 {
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96 SDL_AudioDevice *this;
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97
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98 /* Initialize all variables that we clean on shutdown */
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99 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
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100 if ( this ) {
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101 memset(this, 0, (sizeof *this));
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102 this->hidden = (struct SDL_PrivateAudioData *)
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103 malloc((sizeof *this->hidden));
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104 }
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105 if ( (this == NULL) || (this->hidden == NULL) ) {
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106 SDL_OutOfMemory();
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107 if ( this ) {
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108 free(this);
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109 }
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110 return(0);
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111 }
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112 memset(this->hidden, 0, (sizeof *this->hidden));
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113 audio_fd = -1;
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114
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115 /* Set the function pointers */
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116 this->OpenAudio = DSP_OpenAudio;
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117 this->WaitAudio = DSP_WaitAudio;
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118 this->PlayAudio = DSP_PlayAudio;
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119 this->GetAudioBuf = DSP_GetAudioBuf;
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120 this->CloseAudio = DSP_CloseAudio;
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121
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122 this->free = Audio_DeleteDevice;
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123
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124 return this;
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125 }
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126
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127 AudioBootStrap DSP_bootstrap = {
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128 DSP_DRIVER_NAME, "OSS /dev/dsp standard audio",
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129 Audio_Available, Audio_CreateDevice
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130 };
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131
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132 /* This function waits until it is possible to write a full sound buffer */
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133 static void DSP_WaitAudio(_THIS)
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134 {
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135 /* Not needed at all since OSS handles waiting automagically */
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136 }
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137
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138 static void DSP_PlayAudio(_THIS)
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139 {
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140 if (write(audio_fd, mixbuf, mixlen)==-1)
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141 {
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142 perror("Audio write");
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143 this->enabled = 0;
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144 }
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145
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146 #ifdef DEBUG_AUDIO
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147 fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen);
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148 #endif
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149 }
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150
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151 static Uint8 *DSP_GetAudioBuf(_THIS)
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152 {
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153 return(mixbuf);
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154 }
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155
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156 static void DSP_CloseAudio(_THIS)
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157 {
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158 if ( mixbuf != NULL ) {
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159 SDL_FreeAudioMem(mixbuf);
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160 mixbuf = NULL;
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diff changeset
161 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
162 if ( audio_fd >= 0 ) {
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
163 close(audio_fd);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
164 audio_fd = -1;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
165 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
166 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
167
968
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
168 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec)
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
169 {
968
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
170 char audiodev[1024];
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
171 int format;
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
172 int value;
968
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
173 int frag_spec;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
174 Uint16 test_format;
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
175
968
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
176 /* Open the audio device */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
177 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
178 if ( audio_fd < 0 ) {
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
179 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
180 return(-1);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
181 }
968
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
182 mixbuf = NULL;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
183
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
184 /* Make the file descriptor use blocking writes with fcntl() */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
185 { long flags;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
186 flags = fcntl(audio_fd, F_GETFL);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
187 flags &= ~O_NONBLOCK;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
188 if ( fcntl(audio_fd, F_SETFL, flags) < 0 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
189 SDL_SetError("Couldn't set audio blocking mode");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
190 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
191 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
192 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
193
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
194 /* Get a list of supported hardware formats */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
195 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
196 perror("SNDCTL_DSP_GETFMTS");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
197 SDL_SetError("Couldn't get audio format list");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
198 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
199 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
200
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
201 /* Try for a closest match on audio format */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
202 format = 0;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
203 for ( test_format = SDL_FirstAudioFormat(spec->format);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
204 ! format && test_format; ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
205 #ifdef DEBUG_AUDIO
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
206 fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
207 #endif
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
208 switch ( test_format ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
209 case AUDIO_U8:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
210 if ( value & AFMT_U8 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
211 format = AFMT_U8;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
212 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
213 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
214 case AUDIO_S16LSB:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
215 if ( value & AFMT_S16_LE ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
216 format = AFMT_S16_LE;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
217 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
218 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
219 case AUDIO_S16MSB:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
220 if ( value & AFMT_S16_BE ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
221 format = AFMT_S16_BE;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
222 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
223 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
224 #if 0
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
225 /*
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
226 * These formats are not used by any real life systems so they are not
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
227 * needed here.
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
228 */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
229 case AUDIO_S8:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
230 if ( value & AFMT_S8 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
231 format = AFMT_S8;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
232 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
233 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
234 case AUDIO_U16LSB:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
235 if ( value & AFMT_U16_LE ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
236 format = AFMT_U16_LE;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
237 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
238 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
239 case AUDIO_U16MSB:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
240 if ( value & AFMT_U16_BE ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
241 format = AFMT_U16_BE;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
242 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
243 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
244 #endif
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
245 default:
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
246 format = 0;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
247 break;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
248 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
249 if ( ! format ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
250 test_format = SDL_NextAudioFormat();
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
251 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
252 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
253 if ( format == 0 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
254 SDL_SetError("Couldn't find any hardware audio formats");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
255 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
256 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
257 spec->format = test_format;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
258
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
259 /* Set the audio format */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
260 value = format;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
261 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
262 (value != format) ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
263 perror("SNDCTL_DSP_SETFMT");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
264 SDL_SetError("Couldn't set audio format");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
265 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
266 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
267
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
268 /* Set the number of channels of output */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
269 value = spec->channels;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
270 if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
271 perror("SNDCTL_DSP_CHANNELS");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
272 SDL_SetError("Cannot set the number of channels");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
273 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
274 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
275 spec->channels = value;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
276
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
277 /* Set the DSP frequency */
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
278 value = spec->freq;
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
279 if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) {
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
280 perror("SNDCTL_DSP_SPEED");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
281 SDL_SetError("Couldn't set audio frequency");
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
282 return(-1);
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
283 }
4675910b0b7b Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
Sam Lantinga <slouken@libsdl.org>
parents: 960
diff changeset
284 spec->freq = value;
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
285
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
286 /* Calculate the final parameters for this audio specification */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
287 SDL_CalculateAudioSpec(spec);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
288
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
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289 /* Determine the power of two of the fragment size */
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290 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
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291 if ( (0x01<<frag_spec) != spec->size ) {
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292 SDL_SetError("Fragment size must be a power of two");
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293 return(-1);
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294 }
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295 frag_spec |= 0x00020000; /* two fragments, for low latency */
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296
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297 /* Set the audio buffering parameters */
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298 #ifdef DEBUG_AUDIO
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299 fprintf(stderr, "Requesting %d fragments of size %d\n",
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300 (frag_spec >> 16), 1<<(frag_spec&0xFFFF));
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301 #endif
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302 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
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303 perror("SNDCTL_DSP_SETFRAGMENT");
0
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304 fprintf(stderr, "Warning: Couldn't set audio fragment size\n");
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305 }
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306 #ifdef DEBUG_AUDIO
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307 { audio_buf_info info;
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308 ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info);
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309 fprintf(stderr, "fragments = %d\n", info.fragments);
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310 fprintf(stderr, "fragstotal = %d\n", info.fragstotal);
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311 fprintf(stderr, "fragsize = %d\n", info.fragsize);
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312 fprintf(stderr, "bytes = %d\n", info.bytes);
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313 }
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314 #endif
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315
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316 /* Allocate mixing buffer */
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317 mixlen = spec->size;
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318 mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
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319 if ( mixbuf == NULL ) {
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320 return(-1);
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321 }
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322 memset(mixbuf, spec->silence, spec->size);
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323
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324 /* Get the parent process id (we're the parent of the audio thread) */
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325 parent = getpid();
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326
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327 /* We're ready to rock and roll. :-) */
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328 return(0);
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329 }