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