midi_song.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2005 Angel Ortega <angel@triptico.com>
   5
   6     midi_song.c - MIDI song event stream management
   7
   8     This program is free software; you can redistribute it and/or
   9     modify it under the terms of the GNU General Public License
  10     as published by the Free Software Foundation; either version 2
  11     of the License, or (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     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21
  22     http://www.triptico.com
  23
  24 */
  25
  26 #include "config.h"
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <math.h>
  32 #include <time.h>
  33 #include <unistd.h>
  34
  35 #include "song.h"
  36
  37 /*******************
  38         Data
  39 ********************/
  40
  41 struct midi_ev_generic
  42 {
  43         song_ev_type type;      /* event type */
  44         int msecs;              /* time in milliseconds */
  45         int trk_id;             /* track id */
  46         int channel;            /* MIDI channel */
  47 };
  48
  49 struct midi_ev_program
  50 {
  51         song_ev_type type;      /* SONG_EV_MIDI_PROGRAM */
  52         int msecs;
  53         int trk_id;
  54         int channel;
  55         int program;            /* MIDI program number */
  56 };
  57
  58 struct midi_ev_note_off
  59 {
  60         song_ev_type type;      /* SONG_EV_NOTE_OFF */
  61         int msecs;
  62         int trk_id;
  63         int channel;
  64         int note;               /* MIDI note */
  65 };
  66
  67 struct midi_ev_note_on
  68 {
  69         song_ev_type type;      /* SONG_EV_NOTE_ON */
  70         int msecs;
  71         int trk_id;
  72         int channel;
  73         int note;               /* MIDI note */
  74         int vel;                /* velocity (volume) */
  75 };
  76
  77 union midi_ev
  78 {
  79         struct midi_ev_generic generic;
  80         struct midi_ev_program midi_program;
  81         struct midi_ev_note_on note_on;
  82         struct midi_ev_note_off note_off;
  83 };
  84
  85
  86 /* the MIDI song stream */
  87
  88 static union midi_ev * midi_song=NULL;
  89 static int n_midi_ev=0;
  90
  91 /* the MIDI tracks: just a track/channel table */
  92
  93 #define MIDI_TRACK_NUM 256
  94 static int track_channel[MIDI_TRACK_NUM];
  95
  96 /* MIDI message types */
  97
  98 #define MIDI_MSG_NOTE_ON    0x90
  99 #define MIDI_MSG_NOTE_OFF   0x80
 100 #define MIDI_MSG_CONTROLLER 0xB0
 101 #define MIDI_MSG_PROGRAM    0xC0
 102
 103 /* MIDI device fd */
 104 int midi_fd=2;
 105
 106
 107 /*******************
 108         Code
 109 ********************/
 110
 111 static void add_midi_ev(union midi_ev * e)
 112 /* adds a MIDI song event */
 113 {
 114         /* reallocs */
 115         midi_song=(union midi_ev *)realloc(midi_song,
 116                 (n_midi_ev + 1) * sizeof(union midi_ev));
 117
 118         /* store */
 119         memcpy(&midi_song[n_midi_ev], e, sizeof(union midi_ev));
 120
 121         n_midi_ev++;
 122 }
 123
 124
 125 static int midi_ev_cmp_by_time(const void * v1, const void * v2)
 126 /* MIDI song event compare function for qsort(), by time (for playing) */
 127 {
 128         struct midi_ev_generic * e1;
 129         struct midi_ev_generic * e2;
 130
 131         e1=(struct midi_ev_generic *)v1; e2=(struct midi_ev_generic *)v2;
 132
 133         if(e1->msecs == e2->msecs)
 134                 return(e1->type - e2->type);
 135
 136         return(e1->msecs - e2->msecs);
 137 }
 138
 139
 140 static int midi_song_convert_events(void)
 141 /* converts generic song_ev events to MIDI events */
 142 {
 143         union song_ev * e;
 144         union midi_ev me;
 145         int msecs, msecs_ac;
 146         int time_ac;
 147         int num, den;
 148         double mspw;
 149         int n;
 150         int b_track=-1;
 151
 152         /* resets the MIDI stream */
 153         if(midi_song != NULL)
 154         {
 155                 free(midi_song);
 156                 midi_song=NULL;
 157         }
 158
 159         n_midi_ev=0;
 160
 161         /* sorts the song */
 162         song_sort();
 163
 164         mspw=0;
 165         msecs_ac=0;
 166         time_ac=0;
 167         num=den=4;
 168
 169         /* sets the default track channels sparsely */
 170         for(n=0;n < MIDI_TRACK_NUM;n++)
 171                 track_channel[n]=n % 16;
 172
 173         /* travels the song events generating MIDI song events */
 174         for(n=0;n < n_song_ev;n++)
 175         {
 176                 /* gets the song event */
 177                 e=&song[n];
 178
 179                 /* calculates the msecs */
 180                 msecs=((e->generic.time - time_ac) * mspw) + msecs_ac;
 181
 182                 /* generic event data */
 183                 me.generic.type=e->generic.type;
 184                 me.generic.msecs=msecs;
 185                 me.generic.trk_id=e->generic.trk_id;
 186
 187                 /* if it's not a generic message, set MIDI channel */
 188                 if(e->generic.trk_id >= 0)
 189                         me.generic.channel=track_channel[e->generic.trk_id];
 190
 191                 /* account the biggest track number seen */
 192                 if(b_track < e->generic.trk_id) b_track=e->generic.trk_id;
 193
 194                 switch(e->generic.type)
 195                 {
 196                 case SONG_EV_TEMPO:
 197
 198                         /* updates accumulations */
 199                         msecs_ac += msecs;
 200                         time_ac += e->generic.time;
 201
 202                         /* calculates milliseconds-per-whole based on new tempo */
 203                         mspw = 1000.0 * 60.0;
 204                         mspw /= (e->tempo.tempo / 4.0);
 205
 206                         break;
 207
 208                 case SONG_EV_METER:
 209
 210                         /* just store the values */
 211                         num=e->meter.num;
 212                         den=e->meter.den;
 213
 214                         break;
 215
 216                 case SONG_EV_MEASURE:
 217
 218                         printf("measure boundary check (must be 0): %d\n",
 219                                 ((int) e->generic.time * num) % den);
 220
 221                         break;
 222
 223                 case SONG_EV_MIDI_CHANNEL:
 224
 225                         /* stores the channel for this track */
 226                         track_channel[e->midi_channel.trk_id]=
 227                                 e->midi_channel.channel - 1;
 228                         break;
 229
 230                 case SONG_EV_NOTE:
 231
 232                         /* convert to note on / off pairs */
 233
 234                         me.note_on.type=SONG_EV_NOTE_ON;
 235                         me.note_on.note=e->note.note;
 236                         me.note_on.vel=(int)(e->note.vol * 127.0);
 237
 238                         add_midi_ev(&me);
 239
 240                         msecs += (int)(e->note.len * mspw);
 241
 242                         me.note_off.type=SONG_EV_NOTE_OFF;
 243                         me.note_off.msecs=msecs;
 244
 245                         add_midi_ev(&me);
 246                         break;
 247
 248                 case SONG_EV_MIDI_PROGRAM:
 249
 250                         /* set MIDI program (instrument) */
 251                         me.midi_program.program=e->midi_program.program;
 252
 253                         add_midi_ev(&me);
 254                         break;
 255
 256                 case SONG_EV_SS_PITCH_STRETCH:
 257                 case SONG_EV_SS_WAV:
 258                 case SONG_EV_SS_PAT:
 259                 case SONG_EV_SS_SUSTAIN:
 260                 case SONG_EV_SS_CHANNEL:
 261                 case SONG_EV_SS_EFF_DELAY:
 262                 case SONG_EV_SS_EFF_ECHO:
 263                 case SONG_EV_SS_EFF_COMB:
 264                 case SONG_EV_SS_EFF_ALLPASS:
 265                 case SONG_EV_SS_EFF_FLANGER:
 266                 case SONG_EV_SS_EFF_WOBBLE:
 267                 case SONG_EV_SS_EFF_SQWOBBLE:
 268                 case SONG_EV_SS_EFF_FADER:
 269                 case SONG_EV_SS_EFF_REVERB:
 270                 case SONG_EV_SS_EFF_OFF:
 271
 272                         /* softsynth events are ignored */
 273                         break;
 274
 275                 case SONG_EV_NOTE_ON:
 276                 case SONG_EV_NOTE_OFF:
 277                 case SONG_EV_END:
 278
 279                         /* never found in generic song streams */
 280                         break;
 281                 }
 282         }
 283
 284         /* generates an end of event mark, a time after the last one */
 285         me.generic.type=SONG_EV_END;
 286         me.generic.msecs=msecs + 1000;
 287         add_midi_ev(&me);
 288
 289         /* return the number of tracks */
 290         return(b_track + 1);
 291 }
 292
 293
 294 int midi_song_play(void)
 295 {
 296         union midi_ev * e;
 297         int msecs, msecs_p, msecs_d;
 298         int go;
 299         int n_tracks;
 300         struct timespec ts;
 301         unsigned char midimsg[10];
 302
 303         /* convert the song to MIDI events */
 304         n_tracks=midi_song_convert_events();
 305
 306         /* sort by time */
 307         qsort(midi_song, n_midi_ev, sizeof(union midi_ev), midi_ev_cmp_by_time);
 308
 309         msecs=msecs_p=0;
 310         go=1;
 311         e=midi_song;
 312
 313         /* loop the events */
 314         while(go)
 315         {
 316                 /* process all events for this exact time */
 317                 while(e->generic.msecs == msecs)
 318                 {
 319                         switch(e->generic.type)
 320                         {
 321                         case SONG_EV_NOTE_ON:
 322
 323                                 midimsg[0]=MIDI_MSG_NOTE_ON|e->note_on.channel;
 324                                 midimsg[1]=e->note_on.note;
 325                                 midimsg[2]=e->note_on.vel;
 326
 327                                 write(midi_fd, midimsg, 3);
 328
 329                                 break;
 330
 331                         case SONG_EV_NOTE_OFF:
 332
 333                                 midimsg[0]=MIDI_MSG_NOTE_OFF|e->note_off.channel;
 334                                 midimsg[1]=e->note_off.note;
 335                                 midimsg[2]=0;
 336
 337                                 write(midi_fd, midimsg, 3);
 338
 339                                 break;
 340
 341                         case SONG_EV_MIDI_PROGRAM:
 342
 343                                 midimsg[0]=MIDI_MSG_PROGRAM|e->midi_program.channel;
 344                                 midimsg[1]=e->midi_program.program;
 345
 346                                 write(midi_fd, midimsg, 2);
 347
 348                                 break;
 349
 350                         case SONG_EV_END:
 351
 352                                 go=0;
 353                                 break;
 354
 355                         default:
 356                                 /* ignore the rest */
 357                                 break;
 358                         }
 359
 360                         /* next event */
 361                         e++;
 362                 }
 363
 364                 if(!go)
 365                         break;
 366
 367                 /* get time of next event */
 368                 msecs_p=msecs;
 369                 msecs=e->generic.msecs;
 370                 msecs_d=msecs - msecs_p;
 371
 372                 /* calculate the time to sleep */
 373                 ts.tv_sec=(time_t) msecs_d / 1000;
 374                 ts.tv_nsec=(long) ((msecs_d * 1000000) % 1000000000);
 375
 376                 nanosleep(&ts, NULL);
 377         }
 378
 379         return(0);
 380 }