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