ss_ins.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2006 Angel Ortega <angel@triptico.com>
   5
   6     ss_ins.c - Software synthesizer's instruments
   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
  33 #include "ahxm.h"
  34
  35 /*******************
  36         Data
  37 ********************/
  38
  39 /*******************
  40         Code
  41 ********************/
  42
  43 /**
  44  * ss_ins_init - Initializes an instrument.
  45  * @i: the instrument
  46  *
  47  * Initializes an instrument structure.
  48  */
  49 void ss_ins_init(struct ss_ins * i)
  50 {
  51         memset(i, '\0', sizeof(struct ss_ins));
  52
  53         /* default channels: stereo left and right, full volume */
  54         ss_ins_set_channel(i, 0, 1.0);
  55         ss_ins_set_channel(i, 1, 1.0);
  56
  57         /* sustain shouldn't be 0 to avoid end of note clicks */
  58         ss_ins_set_sustain(i, 50.0);
  59         ss_ins_set_vibrato(i, 0.0, 0.0);
  60         ss_ins_set_portamento(i, 0.0);
  61 }
  62
  63
  64 /**
  65  * ss_ins_disable - Disables an instrument.
  66  * @i: the instrument
  67  *
  68  * Disables an instrument. From now on, no more notes can be played
  69  * on this instrument. If no note are left sounding, ss_ins_frame()
  70  * will return immediately.
  71  */
  72 void ss_ins_disable(struct ss_ins * i)
  73 {
  74         i->disabled = 1;
  75 }
  76
  77
  78 /**
  79  * ss_ins_add_layer - Adds a layer to an instrument.
  80  * @i: the instrument
  81  * @w: wave describing the layer
  82  *
  83  * Adds a layer to an instrument.
  84  *
  85  * Returns 0 if the layer was added successfully.
  86  */
  87 void ss_ins_add_layer(struct ss_ins * i, struct ss_wave * w)
  88 {
  89         /* grow layers */
  90         GROW(i->layers, i->n_layers, struct ss_wave *);
  91
  92         i->layers[i->n_layers] = w;
  93
  94         i->n_layers++;
  95 }
  96
  97
  98 /**
  99  * ss_ins_find_layer - Finds a layer inside an instrument
 100  * @i: the instrument
 101  * @freq: the desired frequency
 102  * @off: pointer to element offset to start searching
 103  *
 104  * Finds a layer inside the @i instrument with a matching @freq, starting
 105  * from the layer number pointed by @off. If a matching layer is found, its
 106  * struct ss_wave is returned and @off is left pointing to the next layer
 107  * (allowing it to be used as an enumerator). If no layer is found, NULL
 108  * is returned.
 109  */
 110 struct ss_wave * ss_ins_find_layer(struct ss_ins * i, double freq, int * off)
 111 {
 112         int n = 0;
 113         struct ss_wave * w = NULL;
 114
 115         /* if off is NULL, point to the first layer */
 116         if(off == NULL) off = &n;
 117
 118         /* find a matching layer, starting from *off */
 119         for(;*off < i->n_layers;(*off)++)
 120         {
 121                 w = i->layers[*off];
 122
 123                 if(freq >= w->min_freq && freq <= w->max_freq)
 124                         break;
 125         }
 126
 127         /* passed the end; none found */
 128         if(*off == i->n_layers)
 129                 w = NULL;
 130         else
 131                 (*off)++;
 132
 133         return(w);
 134 }
 135
 136
 137 /**
 138  * ss_ins_set_channel - Sets the volume for an instrument's channel.
 139  * @i: the instrument
 140  * @channel: channel number
 141  * @vol: volume
 142  *
 143  * Sets the volume for an instrument's channel. If the channel does
 144  * not exist, it's created and space allocated for it in the volume and
 145  * effect dynamic arrays.
 146  */
 147 void ss_ins_set_channel(struct ss_ins * i, int channel, sample_t vol)
 148 {
 149         /* if channel is new, alloc space for it */
 150         if(channel <= i->n_channels)
 151         {
 152                 int n;
 153
 154                 GROW(i->vols, channel, sample_t);
 155                 GROW(i->effs, channel, struct ss_eff *);
 156
 157                 /* fill newly allocated space */
 158                 for(n = i->n_channels;n <= channel;n++)
 159                 {
 160                         i->vols[n] = 1.0;
 161                         i->effs[n] = NULL;
 162                 }
 163
 164                 i->n_channels = channel + 1;
 165         }
 166
 167         /* store volume */
 168         i->vols[channel] = vol;
 169 }
 170
 171
 172 /**
 173  * ss_ins_set_sustain - Sets the sustain for an instrument.
 174  * @i: the instrument
 175  * @sustain: the sustain time in milliseconds
 176  *
 177  * Sets the sustain for an instrument. @sustain is expressed in
 178  * milliseconds.
 179  */
 180 void ss_ins_set_sustain(struct ss_ins * i, double sustain)
 181 {
 182         i->sustain = sustain;
 183 }
 184
 185
 186 /**
 187  * ss_ins_set_vibrato - Sets the vibrato for an instrument.
 188  * @i: the instrument
 189  * @depth: vibrato depth in msecs
 190  * @freq: vibrato frequency in Hzs
 191  *
 192  * Sets the vibrato for an instrument. @depth is expressed in
 193  * milliseconds and @freq in Hzs.
 194  */
 195 void ss_ins_set_vibrato(struct ss_ins * i, double depth, double freq)
 196 {
 197         i->vib_depth = depth;
 198         i->vib_freq = freq;
 199 }
 200
 201
 202 /**
 203  * ss_ins_set_portamento - Sets portamento for an instrument.
 204  * @i: the instrument
 205  * @portamento: portamento value
 206  *
 207  * Sets portamento for an instrument.
 208  */
 209 void ss_ins_set_portamento(struct ss_ins * i, double portamento)
 210 {
 211         i->portamento = portamento;
 212 }
 213
 214
 215 /**
 216  * ss_ins_play - Plays a note given the desired wave.
 217  * @i: the instrument
 218  * @freq: frequency
 219  * @vol: volume
 220  * @note_id: note id
 221  * @w: the wave
 222  *
 223  * Orders the instrument to start playing a note, given a specific wave.
 224  * The wave is usually one of the instrument's layers, but it doesn't
 225  * have to.
 226  *
 227  * Returns -1 if the instrument is disabled, -2 if no free generators
 228  * were found, or 0 if everything went ok.
 229  */
 230 int ss_ins_play(struct ss_ins * i, double freq, sample_t vol, int note_id,
 231         struct ss_wave * w)
 232 {
 233         struct ss_gen * g;
 234
 235         /* if the instrument is disabled, no more notes are allowed */
 236         if(i->disabled) return(-1);
 237
 238         /* get a free generator, or fail */
 239         if((g = ss_gen_alloc(&i->gens)) == NULL)
 240                 return(-2);
 241
 242         /* start the generator */
 243         ss_gen_play(g, freq, vol, note_id, w);
 244
 245         /* set sustain and vibrato */
 246         ss_gen_sustain(g, i->sustain);
 247         ss_gen_vibrato(g, i->vib_depth, i->vib_freq);
 248         ss_gen_portamento(g, i->portamento);
 249
 250         return(1);
 251 }
 252
 253
 254 /**
 255  * ss_ins_note_on - Plays a note.
 256  * @i: the instrument
 257  * @note: MIDI note to be played
 258  * @vol: note volume
 259  * @note_id: note id
 260  *
 261  * Locates a layer to play a note, and starts generators to
 262  * play it. The @note is expressed as a MIDI note and the
 263  * desired volume (from 0 to 1) stored in @vol. The note @id
 264  * should be a positive, unique identifier for this note; no two
 265  * simultaneously playing notes should share this id.
 266  *
 267  * Returns the number of generators that were activated.
 268  */
 269 int ss_ins_note_on(struct ss_ins * i, int note, sample_t vol, int note_id)
 270 {
 271         int n, g;
 272         struct ss_wave * w;
 273         double freq;
 274
 275         freq = ss_note_frequency(note);
 276
 277         for(n = g = 0;(w=ss_ins_find_layer(i, freq, &n)) != NULL;g++)
 278         {
 279                 if(ss_ins_play(i, freq, vol, note_id, w) < 0)
 280                         break;
 281         }
 282
 283         return(g);
 284 }
 285
 286
 287 /**
 288  * ss_ins_note_off - Releases a note.
 289  * @i: the instrument
 290  * @note_id: the id of the note to be released
 291  *
 292  * Releases a note. The generators associated to it will enter release mode.
 293  */
 294 void ss_ins_note_off(struct ss_ins * i, int note_id)
 295 {
 296         struct ss_gen * g;
 297
 298         /* releases all generators with that note_id */
 299         for(g = i->gens;g != NULL;g = g->next)
 300         {
 301                 if(g->note_id == note_id)
 302                         ss_gen_release(g);
 303         }
 304 }
 305
 306
 307 /**
 308  * ss_ins_frame - Generates a frame of samples.
 309  * @i: the instrument
 310  * @frame: array where the output samples will be stored
 311  *
 312  * Generates a frame of samples mixing all the active generators
 313  * of a track.
 314  */
 315 void ss_ins_frame(struct ss_ins * i, sample_t frame[])
 316 {
 317         struct ss_gen * g;
 318         struct ss_gen * t;
 319         int n;
 320         sample_t l_frame[SS_MAX_CHANNELS];
 321
 322         /* if instrument is disabled and there is no more generators, exit */
 323         if(i->disabled && i->gens == NULL) return;
 324
 325         /* resets this local frame */
 326         ss_output_init_frame(l_frame);
 327
 328         /* loops through the generators */
 329         for(g = i->gens;g != NULL;g = t)
 330         {
 331                 t = g->next;
 332
 333                 /* if the generator has stopped, free it */
 334                 if(ss_gen_frame(g, i->n_channels, l_frame))
 335                         ss_gen_free(&i->gens, g);
 336         }
 337
 338         /* loops through the effects and remixes */
 339         for(n = 0;n < i->n_channels;n++)
 340                 frame[n] += ss_eff_process(i->effs[n],
 341                         l_frame[n] * i->vols[n]);
 342 }