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