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 "annhell.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 }
  61
  62
  63 /**
  64  * ss_ins_add_layer - Adds a layer to an instrument.
  65  * @i: the instrument
  66  * @w: wave describing the layer
  67  *
  68  * Adds a layer to an instrument.
  69  *
  70  * Returns 0 if the layer was added successfully.
  71  */
  72 void ss_ins_add_layer(struct ss_ins * i, struct ss_wave * w)
  73 {
  74         /* grow layers */
  75         GROW(i->layers, i->n_layers, struct ss_wave *);
  76
  77         i->layers[i->n_layers] = w;
  78
  79         i->n_layers++;
  80 }
  81
  82
  83 /**
  84  * ss_ins_find_layer - Finds a layer inside an instrument
  85  * @i: the instrument
  86  * @freq: the desired frequency
  87  * @off: pointer to element offset to start searching
  88  *
  89  * Finds a layer inside the @i instrument with a matching @freq, starting
  90  * from the layer number pointed by @off. If a matching layer is found, its
  91  * struct ss_wave is returned and @off is left pointing to the next layer
  92  * (allowing it to be used as an enumerator). If no layer is found, NULL
  93  * is returned.
  94  */
  95 struct ss_wave * ss_ins_find_layer(struct ss_ins * i, double freq, int * off)
  96 {
  97         int n = 0;
  98         struct ss_wave * w = NULL;
  99
 100         /* if off is NULL, point to the first layer */
 101         if(off == NULL) off = &n;
 102
 103         /* find a matching layer, starting from *off */
 104         for(;*off < i->n_layers;(*off)++)
 105         {
 106                 w = i->layers[*off];
 107
 108                 if(freq >= w->min_freq && freq <= w->max_freq)
 109                         break;
 110         }
 111
 112         /* passed the end; none found */
 113         if(*off == i->n_layers)
 114                 w = NULL;
 115         else
 116                 (*off)++;
 117
 118         return(w);
 119 }
 120
 121
 122 /**
 123  * ss_ins_set_channel - Sets the volume for an instrument's channel.
 124  * @i: the instrument
 125  * @channel: channel number
 126  * @vol: volume
 127  *
 128  * Sets the volume for an instrument's channel. If the channel does
 129  * not exist, it's created and space allocated for it in the volume and
 130  * effect dynamic arrays.
 131  */
 132 void ss_ins_set_channel(struct ss_ins * i, int channel, sample_t vol)
 133 {
 134         /* if channel is new, alloc space for it */
 135         if(channel <= i->n_channels)
 136         {
 137                 int n;
 138
 139                 GROW(i->vols, channel, sample_t);
 140                 GROW(i->effs, channel, struct ss_eff *);
 141
 142                 /* fill newly allocated space */
 143                 for(n = i->n_channels;n <= channel;n++)
 144                 {
 145                         i->vols[n] = 1.0;
 146                         i->effs[n] = NULL;
 147                 }
 148
 149                 i->n_channels = channel + 1;
 150         }
 151
 152         /* store volume */
 153         i->vols[channel] = vol;
 154 }
 155
 156
 157 /**
 158  * ss_ins_set_sustain - Sets the sustain for an instrument.
 159  * @i: the instrument
 160  * @sustain: the sustain time in milliseconds
 161  *
 162  * Sets the sustain for an instrument. @sustain is expressed in
 163  * milliseconds.
 164  */
 165 void ss_ins_set_sustain(struct ss_ins * i, double sustain)
 166 {
 167         i->sustain = sustain;
 168 }
 169
 170
 171 /**
 172  * ss_ins_set_vibrato - Sets the vibrato for an instrument.
 173  * @i: the instrument
 174  * @depth: vibrato depth in msecs
 175  * @freq: vibrato frequency in Hzs
 176  *
 177  * Sets the vibrato for an instrument. @depth is expressed in
 178  * milliseconds and @freq in Hzs.
 179  */
 180 void ss_ins_set_vibrato(struct ss_ins * i, double depth, double freq)
 181 {
 182         i->vib_depth = depth;
 183         i->vib_freq = freq;
 184 }
 185
 186
 187 /**
 188  * ss_ins_play - Plays a note given the desired wave.
 189  * @i: the instrument
 190  * @freq: frequency
 191  * @vol: volume
 192  * @note_id: note id
 193  * @w: the wave
 194  *
 195  * Orders the instrument to start playing a note, given a specific wave.
 196  * The wave is usually one of the instrument's layers, but it doesn't
 197  * have to.
 198  *
 199  * Returns zero if there were no free generators, or non-zero otherwise.
 200  */
 201 int ss_ins_play(struct ss_ins * i, double freq, sample_t vol, int note_id,
 202         struct ss_wave * w)
 203 {
 204         struct ss_gen * g;
 205
 206         /* get a free generator, or fail */
 207         if((g = ss_gen_alloc(&i->gens)) == NULL)
 208                 return(0);
 209
 210         /* start the generator */
 211         ss_gen_play(g, freq, vol, note_id, w);
 212
 213         /* set sustain and vibrato */
 214         ss_gen_sustain(g, i->sustain);
 215         ss_gen_vibrato(g, i->vib_depth, i->vib_freq);
 216
 217         return(1);
 218 }
 219
 220
 221 /**
 222  * ss_ins_note_on - Plays a note.
 223  * @i: the instrument
 224  * @note: MIDI note to be played
 225  * @vol: note volume
 226  * @note_id: note id
 227  *
 228  * Locates a layer to play a note, and starts generators to
 229  * play it. The @note is expressed as a MIDI note and the
 230  * desired volume (from 0 to 1) stored in @vol. The note @id
 231  * should be a positive, unique identifier for this note; no two
 232  * simultaneously playing notes should share this id.
 233  *
 234  * Returns the number of generators that were activated.
 235  */
 236 int ss_ins_note_on(struct ss_ins * i, int note, sample_t vol, int note_id)
 237 {
 238         int n, g;
 239         struct ss_wave * w;
 240         double freq;
 241
 242         freq = ss_note_frequency(note);
 243
 244         for(n = g = 0;(w=ss_ins_find_layer(i, freq, &n)) != NULL;g++)
 245         {
 246                 if(!ss_ins_play(i, freq, vol, note_id, w))
 247                         break;
 248         }
 249
 250         return(g);
 251 }
 252
 253
 254 /**
 255  * ss_ins_note_off - Releases a note.
 256  * @i: the instrument
 257  * @note_id: the id of the note to be released
 258  *
 259  * Releases a note. The generators associated to it will enter release mode.
 260  */
 261 void ss_ins_note_off(struct ss_ins * i, int note_id)
 262 {
 263         struct ss_gen * g;
 264
 265         /* releases all generators with that note_id */
 266         for(g = i->gens;g != NULL;g = g->next)
 267         {
 268                 if(g->note_id == note_id)
 269                         ss_gen_release(g);
 270         }
 271 }
 272
 273
 274 /**
 275  * ss_ins_frame - Generates a frame of samples.
 276  * @i: the instrument
 277  * @frame: array where the output samples will be stored
 278  *
 279  * Generates a frame of samples mixing all the active generators
 280  * of a track.
 281  */
 282 void ss_ins_frame(struct ss_ins * i, sample_t frame[])
 283 {
 284         struct ss_gen * g;
 285         struct ss_gen * t;
 286         int n;
 287         sample_t l_frame[SS_MAX_CHANNELS];
 288
 289         /* resets this local frame */
 290         ss_output_init_frame(l_frame);
 291
 292         /* loops through the generators */
 293         for(g = i->gens;g != NULL;g = t)
 294         {
 295                 t = g->next;
 296
 297                 /* if the generator has stopped, free it */
 298                 if(ss_gen_frame(g, i->n_channels, l_frame))
 299                         ss_gen_free(&i->gens, g);
 300         }
 301
 302         /* loops through the effects and remixes */
 303         for(n = 0;n < i->n_channels;n++)
 304                 frame[n] += ss_eff_process(i->effs[n],
 305                         l_frame[n] * i->vols[n]);
 306 }