ss_ins.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2005 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 "annhell.h"
  34
  35 /*******************
  36         Data
  37 ********************/
  38
  39 /*******************
  40         Code
  41 ********************/
  42
  43 /* grows a dynamic array */
  44 #define GROW(b,n,t) b=(t *)realloc(b,((n) + 1) * sizeof(t))
  45
  46 /**
  47  * ss_ins_init - Initializes an instrument.
  48  * @i: the instrument
  49  *
  50  * Initializes an instrument structure.
  51  */
  52 void ss_ins_init(struct ss_ins * i)
  53 {
  54         memset(i, '\0', sizeof(struct ss_ins));
  55
  56         /* default channels: stereo left and right, full volume */
  57         ss_ins_set_channel(i, 0, 1.0);
  58         ss_ins_set_channel(i, 1, 1.0);
  59
  60         /* sustain shouldn't be 0 to avoid end of note clicks */
  61         ss_ins_set_sustain(i, 50.0);
  62         ss_ins_set_vibrato(i, 0.0, 0.0);
  63 }
  64
  65
  66 /**
  67  * ss_ins_add_layer - Adds a layer to an instrument.
  68  * @i: the instrument
  69  * @w: wave describing the layer
  70  *
  71  * Adds a layer to an instrument.
  72  *
  73  * Returns 0 if the layer was added successfully.
  74  */
  75 void ss_ins_add_layer(struct ss_ins * i, struct ss_wave * w)
  76 {
  77         /* grow layers */
  78         GROW(i->layers, i->n_layers, struct ss_wave *);
  79
  80         i->layers[i->n_layers]=w;
  81
  82         i->n_layers++;
  83 }
  84
  85
  86 /**
  87  * ss_ins_find_layer - Finds a layer inside an instrument
  88  * @i: the instrument
  89  * @freq: the desired frequency
  90  * @off: pointer to element offset to start searching
  91  *
  92  * Finds a layer inside the @i instrument with a matching @freq, starting
  93  * from the layer number pointed by @off. If a matching layer is found, its
  94  * struct ss_wave is returned and @off is left pointing to the next layer
  95  * (allowing it to be used as an enumerator). If no layer is found, NULL
  96  * is returned.
  97  */
  98 struct ss_wave * ss_ins_find_layer(struct ss_ins * i, double freq, int * off)
  99 {
 100         struct ss_wave * w=NULL;
 101
 102         /* find a matching layer, starting from *off */
 103         for(;*off < i->n_layers;(*off)++)
 104         {
 105                 w=i->layers[*off];
 106
 107                 if(freq >= w->min_freq && freq <= w->max_freq)
 108                         break;
 109         }
 110
 111         /* passed the end; none found */
 112         if(*off == i->n_layers)
 113                 w=NULL;
 114         else
 115                 (*off)++;
 116
 117         return(w);
 118 }
 119
 120
 121 /**
 122  * ss_ins_set_channel - Sets the volume for an instrument's channel.
 123  * @i: the instrument
 124  * @channel: channel number
 125  * @vol: volume
 126  *
 127  * Sets the volume for an instrument's channel. If the channel does
 128  * not exist, it's created and space allocated for it in the volume and
 129  * effect dynamic arrays.
 130  */
 131 void ss_ins_set_channel(struct ss_ins * i, int channel, float vol)
 132 {
 133         /* if channel is new, alloc space for it */
 134         if(channel <= i->n_channels)
 135         {
 136                 int n;
 137
 138                 GROW(i->vols, channel, float);
 139                 GROW(i->effs, channel, struct ss_eff *);
 140
 141                 /* fill newly allocated space */
 142                 for(n=i->n_channels;n <= channel;n++)
 143                 {
 144                         i->vols[n]=1.0;
 145                         i->effs[n]=NULL;
 146                 }
 147
 148                 i->n_channels=channel + 1;
 149         }
 150
 151         /* store volume */
 152         i->vols[channel]=vol;
 153 }
 154
 155
 156 /**
 157  * ss_ins_set_sustain - Sets the sustain for an instrument.
 158  * @i: the instrument
 159  * @sustain: the sustain time in milliseconds
 160  *
 161  * Sets the sustain for an instrument. @sustain is expressed in
 162  * milliseconds.
 163  */
 164 void ss_ins_set_sustain(struct ss_ins * i, double sustain)
 165 {
 166         i->sustain=sustain;
 167 }
 168
 169
 170 /**
 171  * ss_ins_set_vibrato - Sets the vibrato for an instrument.
 172  * @i: the instrument
 173  * @depth: vibrato depth in msecs
 174  * @freq: vibrato frequency in Hzs
 175  *
 176  * Sets the vibrato for an instrument. @depth is expressed in
 177  * milliseconds and @freq in Hzs.
 178  */
 179 void ss_ins_set_vibrato(struct ss_ins * i, double depth, double freq)
 180 {
 181         i->vib_depth=depth;
 182         i->vib_freq=freq;
 183 }
 184
 185
 186 /**
 187  * ss_ins_play - Plays a note given the desired wave.
 188  * @i: the instrument
 189  * @w: the wave
 190  * @freq: frequency
 191  * @vol: volume
 192  * @note_id: note id
 193  *
 194  * Orders the instrument to start playing a note, given a specific wave.
 195  * The wave is usually one of the instrument's layers, but it doesn't
 196  * have to.
 197  *
 198  * Returns zero if there were no free generators, or non-zero otherwise.
 199  */
 200 int ss_ins_play(struct ss_ins * i, double freq, float vol, int note_id,
 201         struct ss_wave * w)
 202 {
 203         struct ss_gen * g;
 204
 205         /* get a free generator, or fail */
 206         if((g=ss_gen_alloc(&i->gens)) == NULL)
 207                 return(0);
 208
 209         /* start the generator */
 210         ss_gen_play(g, freq, vol, note_id, w);
 211
 212         /* set sustain and vibrato */
 213         ss_gen_sustain(g, i->sustain);
 214         ss_gen_vibrato(g, i->vib_depth, i->vib_freq);
 215
 216         return(1);
 217 }
 218
 219
 220 /**
 221  * ss_ins_note_on - Plays a note.
 222  * @i: the instrument
 223  * @note: MIDI note to be played
 224  * @vol: note volume
 225  * @note_id: note id
 226  *
 227  * Locates a layer to play a note, and starts generators to
 228  * play it. The @note is expressed as a MIDI note and the
 229  * desired volume (from 0 to 1) stored in @vol. The note @id
 230  * should be a positive, unique identifier for this note; no two
 231  * simultaneously playing notes should share this id.
 232  *
 233  * Returns the number of generators that were activated.
 234  */
 235 int ss_ins_note_on(struct ss_ins * i, int note, float vol, int note_id)
 236 {
 237         int n, g;
 238         struct ss_wave * w;
 239         double freq;
 240
 241         freq=ss_note_frequency(note);
 242
 243         for(n=g=0;(w=ss_ins_find_layer(i, freq, &n)) != NULL;g++)
 244         {
 245                 if(!ss_ins_play(i, freq, vol, note_id, w))
 246                         break;
 247         }
 248
 249         return(g);
 250 }
 251
 252
 253 /**
 254  * ss_ins_note_off - Releases a note.
 255  * @i: the instrument
 256  * @note_id: the id of the note to be released
 257  *
 258  * Releases a note. The generators associated to it will enter release mode.
 259  */
 260 void ss_ins_note_off(struct ss_ins * i, int note_id)
 261 {
 262         struct ss_gen * g;
 263
 264         /* releases all generators with that note_id */
 265         for(g=i->gens;g != NULL;g=g->next)
 266         {
 267                 if(g->note_id == note_id)
 268                         ss_gen_release(g);
 269         }
 270 }
 271
 272
 273 /**
 274  * ss_ins_frame - Generates a frame of samples.
 275  * @i: the instrument
 276  * @frame: array where the output samples will be stored
 277  *
 278  * Generates a frame of samples mixing all the active generators
 279  * of a track.
 280  */
 281 void ss_ins_frame(struct ss_ins * i, float frame[])
 282 {
 283         struct ss_gen * g;
 284         struct ss_gen * t;
 285         int n;
 286         float l_frame[SS_MAX_CHANNELS];
 287
 288         /* resets this local frame */
 289         ss_output_init_frame(l_frame);
 290
 291         /* loops through the generators */
 292         for(g=i->gens;g != NULL;g=t)
 293         {
 294                 t=g->next;
 295
 296                 /* if the generator has stopped, free it */
 297                 if(ss_gen_frame(g, i->n_channels, l_frame))
 298                         ss_gen_free(&i->gens, g);
 299         }
 300
 301         /* loops through the effects and remixes */
 302         for(n=0;n < i->n_channels;n++)
 303                 frame[n] += ss_eff_process(i->effs[n],
 304                         l_frame[n] * i->vols[n]);
 305 }