Mercurial > sdl-ios-xcode
annotate src/audio/arts/SDL_artsaudio.c @ 261:1c5f68da5fc2
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| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Fri, 04 Jan 2002 20:48:51 +0000 |
| parents | e8157fcb3114 |
| children | d2d48e10f370 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
| 3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga | |
| 4 | |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
0
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changeset
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20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* Allow access to a raw mixing buffer */ | |
| 29 | |
| 30 #include <sys/types.h> | |
| 31 #include <stdlib.h> | |
| 32 #include <stdio.h> | |
| 33 #include <string.h> | |
| 34 #include <errno.h> | |
| 35 #include <signal.h> | |
| 36 #include <unistd.h> | |
| 37 | |
| 38 #include "SDL_audio.h" | |
| 39 #include "SDL_error.h" | |
| 40 #include "SDL_audiomem.h" | |
| 41 #include "SDL_audio_c.h" | |
| 42 #include "SDL_timer.h" | |
| 43 #include "SDL_audiodev_c.h" | |
| 44 #include "SDL_artsaudio.h" | |
| 45 | |
| 46 /* The tag name used by artsc audio */ | |
| 47 #define ARTSC_DRIVER_NAME "artsc" | |
| 48 | |
| 49 /* Audio driver functions */ | |
| 50 static int ARTSC_OpenAudio(_THIS, SDL_AudioSpec *spec); | |
| 51 static void ARTSC_WaitAudio(_THIS); | |
| 52 static void ARTSC_PlayAudio(_THIS); | |
| 53 static Uint8 *ARTSC_GetAudioBuf(_THIS); | |
| 54 static void ARTSC_CloseAudio(_THIS); | |
| 55 | |
| 56 /* Audio driver bootstrap functions */ | |
| 57 | |
| 58 static int Audio_Available(void) | |
| 59 { | |
| 60 if(arts_init()) | |
| 61 return 0; | |
| 62 else | |
| 63 return 1; | |
| 64 } | |
| 65 | |
| 66 static void Audio_DeleteDevice(SDL_AudioDevice *device) | |
| 67 { | |
| 68 free(device->hidden); | |
| 69 free(device); | |
| 70 } | |
| 71 | |
| 72 static SDL_AudioDevice *Audio_CreateDevice(int devindex) | |
| 73 { | |
| 74 SDL_AudioDevice *this; | |
| 75 | |
| 76 /* Initialize all variables that we clean on shutdown */ | |
| 77 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice)); | |
| 78 if ( this ) { | |
| 79 memset(this, 0, (sizeof *this)); | |
| 80 this->hidden = (struct SDL_PrivateAudioData *) | |
| 81 malloc((sizeof *this->hidden)); | |
| 82 } | |
| 83 if ( (this == NULL) || (this->hidden == NULL) ) { | |
| 84 SDL_OutOfMemory(); | |
| 85 if ( this ) { | |
| 86 free(this); | |
| 87 } | |
| 88 return(0); | |
| 89 } | |
| 90 memset(this->hidden, 0, (sizeof *this->hidden)); | |
| 91 stream = 0; | |
| 92 | |
| 93 /* Set the function pointers */ | |
| 94 this->OpenAudio = ARTSC_OpenAudio; | |
| 95 this->WaitAudio = ARTSC_WaitAudio; | |
| 96 this->PlayAudio = ARTSC_PlayAudio; | |
| 97 this->GetAudioBuf = ARTSC_GetAudioBuf; | |
| 98 this->CloseAudio = ARTSC_CloseAudio; | |
| 99 | |
| 100 this->free = Audio_DeleteDevice; | |
| 101 | |
| 102 return this; | |
| 103 } | |
| 104 | |
| 105 AudioBootStrap ARTSC_bootstrap = { | |
| 106 ARTSC_DRIVER_NAME, "Analog Realtime Synthesizer", | |
| 107 Audio_Available, Audio_CreateDevice | |
| 108 }; | |
| 109 | |
| 110 /* This function waits until it is possible to write a full sound buffer */ | |
| 111 static void ARTSC_WaitAudio(_THIS) | |
| 112 { | |
| 113 Sint32 ticks; | |
| 114 | |
| 115 /* Check to see if the thread-parent process is still alive */ | |
| 116 { static int cnt = 0; | |
| 117 /* Note that this only works with thread implementations | |
| 118 that use a different process id for each thread. | |
| 119 */ | |
| 120 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */ | |
| 121 if ( kill(parent, 0) < 0 ) { | |
| 122 this->enabled = 0; | |
| 123 } | |
| 124 } | |
| 125 } | |
| 126 | |
| 127 /* Use timer for general audio synchronization */ | |
| 128 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS; | |
| 129 if ( ticks > 0 ) { | |
| 130 SDL_Delay(ticks); | |
| 131 } | |
| 132 } | |
| 133 | |
| 134 static void ARTSC_PlayAudio(_THIS) | |
| 135 { | |
| 136 int written; | |
| 137 | |
| 138 /* Write the audio data */ | |
| 139 written = arts_write(stream, mixbuf, mixlen); | |
| 140 | |
| 141 /* If timer synchronization is enabled, set the next write frame */ | |
| 142 if ( frame_ticks ) { | |
| 143 next_frame += frame_ticks; | |
| 144 } | |
| 145 | |
| 146 /* If we couldn't write, assume fatal error for now */ | |
| 147 if ( written < 0 ) { | |
| 148 this->enabled = 0; | |
| 149 } | |
| 150 #ifdef DEBUG_AUDIO | |
| 151 fprintf(stderr, "Wrote %d bytes of audio data\n", written); | |
| 152 #endif | |
| 153 } | |
| 154 | |
| 155 static Uint8 *ARTSC_GetAudioBuf(_THIS) | |
| 156 { | |
| 157 return(mixbuf); | |
| 158 } | |
| 159 | |
| 160 static void ARTSC_CloseAudio(_THIS) | |
| 161 { | |
| 162 if ( mixbuf != NULL ) { | |
| 163 SDL_FreeAudioMem(mixbuf); | |
| 164 mixbuf = NULL; | |
| 165 } | |
| 166 if ( stream ) { | |
| 167 arts_close_stream(stream); | |
| 168 stream = 0; | |
| 169 } | |
| 170 } | |
| 171 | |
| 172 static int ARTSC_OpenAudio(_THIS, SDL_AudioSpec *spec) | |
| 173 { | |
| 174 int bits, frag_spec; | |
| 175 Uint16 test_format, format; | |
| 176 | |
| 177 /* Reset the timer synchronization flag */ | |
| 178 frame_ticks = 0.0; | |
| 179 | |
| 180 mixbuf = NULL; | |
| 181 | |
| 182 /* Try for a closest match on audio format */ | |
| 183 format = 0; | |
| 184 bits = 0; | |
| 185 for ( test_format = SDL_FirstAudioFormat(spec->format); | |
| 186 ! format && test_format; ) { | |
| 187 #ifdef DEBUG_AUDIO | |
| 188 fprintf(stderr, "Trying format 0x%4.4x\n", test_format); | |
| 189 #endif | |
| 190 switch ( test_format ) { | |
| 191 case AUDIO_U8: | |
| 192 bits = 8; | |
| 193 format = 1; | |
| 194 break; | |
| 195 case AUDIO_S16LSB: | |
| 196 bits = 16; | |
| 197 format = 1; | |
| 198 break; | |
| 199 default: | |
| 200 format = 0; | |
| 201 break; | |
| 202 } | |
| 203 if ( ! format ) { | |
| 204 test_format = SDL_NextAudioFormat(); | |
| 205 } | |
| 206 } | |
| 207 if ( format == 0 ) { | |
| 208 SDL_SetError("Couldn't find any hardware audio formats"); | |
| 209 return(-1); | |
| 210 } | |
| 211 spec->format = test_format; | |
| 212 | |
| 213 stream = arts_play_stream(spec->freq, bits, spec->channels, "SDL"); | |
| 214 | |
| 215 /* Calculate the final parameters for this audio specification */ | |
| 216 SDL_CalculateAudioSpec(spec); | |
| 217 | |
| 218 /* Determine the power of two of the fragment size */ | |
| 219 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec ); | |
| 220 if ( (0x01<<frag_spec) != spec->size ) { | |
| 221 SDL_SetError("Fragment size must be a power of two"); | |
| 222 return(-1); | |
| 223 } | |
| 224 frag_spec |= 0x00020000; /* two fragments, for low latency */ | |
| 225 | |
| 226 #ifdef ARTS_P_PACKET_SETTINGS | |
| 227 arts_stream_set(stream, ARTS_P_PACKET_SETTINGS, frag_spec); | |
| 228 #else | |
| 229 arts_stream_set(stream, ARTS_P_PACKET_SIZE, frag_spec&0xffff); | |
| 230 arts_stream_set(stream, ARTS_P_PACKET_COUNT, frag_spec>>16); | |
| 231 #endif | |
| 232 spec->size = arts_stream_get(stream, ARTS_P_PACKET_SIZE); | |
| 233 | |
| 234 /* Allocate mixing buffer */ | |
| 235 mixlen = spec->size; | |
| 236 mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen); | |
| 237 if ( mixbuf == NULL ) { | |
| 238 return(-1); | |
| 239 } | |
| 240 memset(mixbuf, spec->silence, spec->size); | |
| 241 | |
| 242 /* Get the parent process id (we're the parent of the audio thread) */ | |
| 243 parent = getpid(); | |
| 244 | |
| 245 /* We're ready to rock and roll. :-) */ | |
| 246 return(0); | |
| 247 } |