share/audio.c

   1 /*
   2  * Copyright (C) 2003 Robert Kooima
   3  *
   4  * NEVERBALL is  free software; you can redistribute  it and/or modify
   5  * it under the  terms of the GNU General  Public License as published
   6  * by the Free  Software Foundation; either version 2  of the License,
   7  * or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT  ANY  WARRANTY;  without   even  the  implied  warranty  of
  11  * MERCHANTABILITY or  FITNESS FOR A PARTICULAR PURPOSE.   See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #include <SDL.h>
  16
  17 #define OV_EXCLUDE_STATIC_CALLBACKS
  18 #include <vorbis/codec.h>
  19 #include <vorbis/vorbisfile.h>
  20
  21 #include <string.h>
  22 #include <stdlib.h>
  23
  24 #include "config.h"
  25 #include "audio.h"
  26 #include "common.h"
  27 #include "fs.h"
  28 #include "fs_ov.h"
  29
  30 /*---------------------------------------------------------------------------*/
  31
  32 #define AUDIO_RATE 44100
  33 #define AUDIO_CHAN 2
  34
  35 struct voice
  36 {
  37     OggVorbis_File  vf;
  38     float          amp;
  39     float         damp;
  40     int           chan;
  41     int           play;
  42     int           loop;
  43     char         *name;
  44     struct voice *next;
  45 };
  46
  47 static int   audio_state = 0;
  48 static float sound_vol   = 1.0f;
  49 static float music_vol   = 1.0f;
  50
  51 static SDL_AudioSpec spec;
  52
  53 static struct voice *music  = NULL;
  54 static struct voice *queue  = NULL;
  55 static struct voice *voices = NULL;
  56 static short        *buffer = NULL;
  57
  58 static ov_callbacks callbacks = {
  59     fs_ov_read, fs_ov_seek, fs_ov_close, fs_ov_tell
  60 };
  61
  62 /*---------------------------------------------------------------------------*/
  63
  64 #define MIX(d, s) {                           \
  65         int T = (int) (d) + (int) (s);        \
  66         if      (T >  32767) (d) =  32767;    \
  67         else if (T < -32768) (d) = -32768;    \
  68         else                 (d) = (short) T; \
  69     }
  70
  71 static int voice_step(struct voice *V, float volume, Uint8 *stream, int length)
  72 {
  73 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
  74     int order = 1;
  75 #else
  76     int order = 0;
  77 #endif
  78
  79     short *obuf = (short *) stream;
  80     char  *ibuf = (char  *) buffer;
  81
  82     int i, b = 0, n = 1, c = 0, r = 0;
  83
  84     /* Compute the total request size for the current stream. */
  85
  86     if (V->chan == 1) r = length / 2;
  87     if (V->chan == 2) r = length    ;
  88
  89     /* While data is coming in and data is still needed... */
  90
  91     while (n > 0 && r > 0)
  92     {
  93         /* Read audio from the stream. */
  94
  95         if ((n = (int) ov_read(&V->vf, ibuf, r, order, 2, 1, &b)) > 0)
  96         {
  97             /* Mix mono audio. */
  98
  99             if (V->chan == 1)
 100                 for (i = 0; i < n / 2; i += 1)
 101                 {
 102                     short M = (short) (V->amp * volume * buffer[i]);
 103
 104                     MIX(obuf[c], M); c++;
 105                     MIX(obuf[c], M); c++;
 106
 107                     V->amp += V->damp;
 108
 109                     if (V->amp < 0.0f) V->amp = 0.0;
 110                     if (V->amp > 1.0f) V->amp = 1.0;
 111                 }
 112
 113             /* Mix stereo audio. */
 114
 115             if (V->chan == 2)
 116                 for (i = 0; i < n / 2; i += 2)
 117                 {
 118                     short L = (short) (V->amp * volume * buffer[i + 0]);
 119                     short R = (short) (V->amp * volume * buffer[i + 1]);
 120
 121                     MIX(obuf[c], L); c++;
 122                     MIX(obuf[c], R); c++;
 123
 124                     V->amp += V->damp;
 125
 126                     if (V->amp < 0.0f) V->amp = 0.0;
 127                     if (V->amp > 1.0f) V->amp = 1.0;
 128                 }
 129
 130             r -= n;
 131         }
 132         else
 133         {
 134             /* We're at EOF.  Loop or end the voice. */
 135
 136             if (V->loop)
 137             {
 138                 ov_raw_seek(&V->vf, 0);
 139                 n = 1;
 140             }
 141             else return 1;
 142         }
 143     }
 144     return 0;
 145 }
 146
 147 static struct voice *voice_init(const char *filename, float a)
 148 {
 149     struct voice *V;
 150     fs_file      fp;
 151
 152     /* Allocate and initialize a new voice structure. */
 153
 154     if ((V = (struct voice *) calloc(1, sizeof (struct voice))))
 155     {
 156         /* Note the name. */
 157
 158         V->name = strdup(filename);
 159
 160         /* Attempt to open the named Ogg stream. */
 161
 162         if ((fp = fs_open(filename, "r")))
 163         {
 164             if (ov_open_callbacks(fp, &V->vf, NULL, 0, callbacks) == 0)
 165             {
 166                 vorbis_info *info = ov_info(&V->vf, -1);
 167
 168                 /* On success, configure the voice. */
 169
 170                 V->amp  = a;
 171                 V->damp = 0;
 172                 V->chan = info->channels;
 173                 V->play = 1;
 174                 V->loop = 0;
 175
 176                 if (V->amp > 1.0f) V->amp = 1.0;
 177                 if (V->amp < 0.0f) V->amp = 0.0;
 178
 179                 /* The file will be closed when the Ogg is cleared. */
 180             }
 181             else fs_close(fp);
 182         }
 183     }
 184     return V;
 185 }
 186
 187 static void voice_free(struct voice *V)
 188 {
 189     ov_clear(&V->vf);
 190
 191     free(V->name);
 192     free(V);
 193 }
 194
 195 /*---------------------------------------------------------------------------*/
 196
 197 static void audio_step(void *data, Uint8 *stream, int length)
 198 {
 199     struct voice *V = voices;
 200     struct voice *P = NULL;
 201
 202     /* Zero the output buffer. */
 203
 204     memset(stream, 0, length);
 205
 206     /* Mix the background music. */
 207
 208     if (music)
 209     {
 210         voice_step(music, music_vol, stream, length);
 211
 212         /* If the track has faded out, move to a queued track. */
 213
 214         if (music->amp <= 0.0f && music->damp < 0.0f && queue)
 215         {
 216             voice_free(music);
 217             music = queue;
 218             queue = NULL;
 219         }
 220     }
 221
 222     /* Iterate over all active voices. */
 223
 224     while (V)
 225     {
 226         /* Mix this voice. */
 227
 228         if (V->play && voice_step(V, sound_vol, stream, length))
 229         {
 230             /* Delete a finished voice... */
 231
 232             struct voice *T = V;
 233
 234             if (P)
 235                 V = P->next = V->next;
 236             else
 237                 V = voices  = V->next;
 238
 239             voice_free(T);
 240         }
 241         else
 242         {
 243             /* ... or continue to the next. */
 244
 245             P = V;
 246             V = V->next;
 247         }
 248     }
 249 }
 250
 251 /*---------------------------------------------------------------------------*/
 252
 253 void audio_init(void)
 254 {
 255     audio_state = 0;
 256
 257     /* Configure the audio. */
 258
 259     spec.format   = AUDIO_S16SYS;
 260     spec.channels = AUDIO_CHAN;
 261     spec.samples  = config_get_d(CONFIG_AUDIO_BUFF);
 262     spec.freq     = AUDIO_RATE;
 263     spec.callback = audio_step;
 264
 265     /* Allocate an input buffer. */
 266
 267     if ((buffer = (short *) malloc(spec.samples * 4)))
 268     {
 269         /* Start the audio thread. */
 270
 271         if (SDL_OpenAudio(&spec, NULL) == 0)
 272         {
 273             audio_state = 1;
 274             SDL_PauseAudio(0);
 275         }
 276         else log_printf("Failure to open audio device (%s)\n", SDL_GetError());
 277     }
 278
 279     /* Set the initial volumes. */
 280
 281     audio_volume(config_get_d(CONFIG_SOUND_VOLUME),
 282                  config_get_d(CONFIG_MUSIC_VOLUME));
 283 }
 284
 285 void audio_free(void)
 286 {
 287     /* Halt the audio thread. */
 288
 289     SDL_CloseAudio();
 290
 291     /* Release the input buffer. */
 292
 293     free(buffer);
 294
 295     /* Ogg streams and voice structure remain open to allow quality setting. */
 296 }
 297
 298 void audio_play(const char *filename, float a)
 299 {
 300     if (audio_state)
 301     {
 302         struct voice *V;
 303
 304         /* If we're already playing this sound, preempt the running copy. */
 305
 306         SDL_LockAudio();
 307         {
 308             for (V = voices; V; V = V->next)
 309                 if (strcmp(V->name, filename) == 0)
 310                 {
 311                     ov_raw_seek(&V->vf, 0);
 312
 313                     V->amp = a;
 314
 315                     if (V->amp > 1.0f) V->amp = 1.0;
 316                     if (V->amp < 0.0f) V->amp = 0.0;
 317
 318                     SDL_UnlockAudio();
 319                     return;
 320                 }
 321         }
 322         SDL_UnlockAudio();
 323
 324         /* Create a new voice structure. */
 325
 326         V = voice_init(filename, a);
 327
 328         /* Add it to the list of sounding voices. */
 329
 330         SDL_LockAudio();
 331         {
 332             V->next = voices;
 333             voices  = V;
 334         }
 335         SDL_UnlockAudio();
 336     }
 337 }
 338
 339 /*---------------------------------------------------------------------------*/
 340
 341 void audio_music_play(const char *filename)
 342 {
 343     if (audio_state)
 344     {
 345         audio_music_stop();
 346
 347         SDL_LockAudio();
 348         {
 349             if ((music = voice_init(filename, 0.0f)))
 350             {
 351                 music->loop = 1;
 352             }
 353         }
 354         SDL_UnlockAudio();
 355     }
 356 }
 357
 358 void audio_music_queue(const char *filename, float t)
 359 {
 360     if (audio_state)
 361     {
 362         SDL_LockAudio();
 363         {
 364             if ((queue = voice_init(filename, 0.0f)))
 365             {
 366                 queue->loop = 1;
 367
 368                 if (t > 0.0f)
 369                     queue->damp = +1.0f / (AUDIO_RATE * t);
 370             }
 371         }
 372         SDL_UnlockAudio();
 373     }
 374 }
 375
 376 void audio_music_stop(void)
 377 {
 378     if (audio_state)
 379     {
 380         SDL_LockAudio();
 381         {
 382             if (music)
 383             {
 384                 voice_free(music);
 385             }
 386             music = NULL;
 387         }
 388         SDL_UnlockAudio();
 389     }
 390 }
 391
 392 /*---------------------------------------------------------------------------*/
 393
 394 void audio_music_fade_out(float t)
 395 {
 396     SDL_LockAudio();
 397     {
 398         if (music) music->damp = -1.0f / (AUDIO_RATE * t);
 399     }
 400     SDL_UnlockAudio();
 401 }
 402
 403 void audio_music_fade_in(float t)
 404 {
 405     SDL_LockAudio();
 406     {
 407         if (music) music->damp = +1.0f / (AUDIO_RATE * t);
 408     }
 409     SDL_UnlockAudio();
 410 }
 411
 412 void audio_music_fade_to(float t, const char *filename)
 413 {
 414     if (music)
 415     {
 416         if (strcmp(filename, music->name) != 0)
 417         {
 418             audio_music_fade_out(t);
 419             audio_music_queue(filename, t);
 420         }
 421         else
 422         {
 423             /*
 424              * We're fading to the current track.  Chances are,
 425              * whatever track is still in the queue, we don't want to
 426              * hear it anymore.
 427              */
 428
 429             if (queue)
 430             {
 431                 voice_free(queue);
 432                 queue = NULL;
 433             }
 434
 435             audio_music_fade_in(t);
 436         }
 437     }
 438     else
 439     {
 440         audio_music_play(filename);
 441         audio_music_fade_in(t);
 442     }
 443 }
 444
 445 void audio_volume(int s, int m)
 446 {
 447     sound_vol = (float) s / 10.0f;
 448     music_vol = (float) m / 10.0f;
 449 }
 450
 451 /*---------------------------------------------------------------------------*/