synth.c

   1 /*
   2    Cantaveria - action adventure platform game
   3    Copyright (C) 2009 2010 Evan Rinehart
   4
   5    This program is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License
   7    as published by the Free Software Foundation; either version 2
   8    of the License, or (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to
  17
  18    The Free Software Foundation, Inc.
  19    51 Franklin Street, Fifth Floor
  20    Boston, MA  02110-1301, USA
  21
  22    evanrinehart@gmail.com
  23 */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <math.h>
  28
  29 #include <util.h>
  30 #include <list.h>
  31 #include <org.h>
  32 #include <synth.h>
  33 #include <seq.h>
  34
  35 /*
  36 timing stuff
  37
  38 ticks -   384 per beat     (tpb)
  39 beats -   120 per minute   (bpm)
  40 samples - 22050 per second (srate)
  41
  42 control happens on tick boundaries
  43 control must take effect on nearest sample boundary
  44
  45 samples per tick = (srate*60) / (bpm*tpb)
  46 which in the above example = 28 and 32760/46080
  47
  48 */
  49
  50 typedef struct {
  51         float L, R, V;
  52         mix_callback mix;
  53         control_callback control;
  54         cleanup_callback cleanup;
  55         void* data;
  56 } channel;
  57
  58 int srate;
  59
  60 int serr = 0; // 1/1000 of a sample
  61
  62 int tick;
  63 int terr = 0; // 1/(bpm*tpb) of a sample
  64 int terrd = 46080; //bpm * tpb
  65
  66
  67 channel channels[16];
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78 void dummy_mix(void* v, float f[], int i){}
  79 void dummy_control(void* v, int a, int b, int c, int d){}
  80 void dummy_cleanup(void* v){}
  81
  82 channel make_dummy_channel(){
  83         channel ch;
  84         ch.L = 1;
  85         ch.R = 1;
  86         ch.V = 1;
  87         ch.mix = dummy_mix;
  88         ch.cleanup = dummy_cleanup;
  89         ch.control = dummy_control;
  90         ch.data = NULL;
  91         return ch;
  92 }
  93
  94 channel make_channel_from_instrument(enum instrument_name name){
  95         channel ch = make_dummy_channel();
  96         instrument ins = load_instrument(name);
  97         ch.mix = ins.mix;
  98         ch.control = ins.control;
  99         ch.cleanup = ins.cleanup;
 100         ch.data = ins.data;
 101         return ch;
 102 }
 103
 104
 105
 106 void set_music_volume(int percent){
 107
 108 }
 109
 110 void cut_music(){
 111
 112 }
 113
 114 void fade_clear(){
 115
 116 }
 117
 118 void fadeout(int seconds){
 119
 120 }
 121
 122
 123
 124 void mix(channel* ch, float in[], float left[], float right[], int count){
 125         int i;
 126         for(i=0; i<count; i++){
 127                 left[i] += in[i] * ch->L * ch->V;
 128                 right[i] += in[i] * ch->R * ch->V;
 129         }
 130 }
 131
 132 void zero(float buf[], int count){
 133         int i;
 134         for(i=0; i<count; i++){
 135                 buf[i] = 0;
 136         }
 137 }
 138
 139 void reduce(float buf[], int count, float factor){
 140         int i;
 141         for(i=0; i<count; i++){
 142                 buf[i] /= factor;
 143         }
 144 }
 145
 146 void clip(float buf[], int count){
 147         int i;
 148         int clipped = 0;
 149         float avg = 0;
 150         for(i=0; i<count; i++){
 151                 avg += buf[i]*buf[i];
 152                 if(buf[i] > 1.0){
 153                         clipped = 1;
 154                         buf[i] = 1.0;
 155                 }
 156                 else if(buf[i] < -1.0) buf[i] = -1.0;
 157         }
 158
 159         if(clipped){
 160                 printf("synth: clipping distortion due to output overload\n");
 161         }
 162
 163         avg /= count?count:1;
 164         avg = sqrt(avg);
 165 }
 166
 167 void generate(float left[], float right[], int count){
 168         float buf[4096];
 169         int i;
 170         float V = 1.0f;
 171
 172         zero(left, count);
 173         zero(right, count);
 174         for(i=0; i<16; i++){
 175                 channel* ch = &(channels[i]);
 176                 zero(buf, count);
 177                 ch->mix(ch->data, buf, count);
 178                 mix(ch, buf, left, right, count);
 179         }
 180         reduce(left, count, 16.0f/V);
 181         reduce(right, count, 16.0f/V);
 182         clip(left, count);
 183         clip(right, count);
 184 }
 185
 186 void control(event* e){
 187         if(e == NULL) return;
 188         int chan = e->chan;
 189         int type = e->type;
 190         int val1 = e->val1;
 191         int val2 = e->val2;
 192         int val  = (e->val2 << 7) | e->val1;
 193         channel* ch = &(channels[chan]);
 194
 195         switch(type){
 196                 case EVX_MUSICVOLUME: set_music_volume(val1); break;
 197                 case EVX_MUSICCUT: cut_music(); break;
 198                 case EVX_FADECLEAR: fade_clear(); break;
 199                 case EVX_FADEOUT: fadeout(val1); break;
 200                 default: ch->control(ch->data, type, val1, val2, val); break;
 201         }
 202 }
 203
 204 void immediate_control(){
 205         event* e = seq_get_immediate();
 206         while(e){
 207                 control(e);
 208                 e = seq_get_immediate();
 209         }
 210 }
 211
 212 void synth_generate(float left[], float right[], int samples){
 213         int i=0;
 214         int remaining = samples;
 215         int used = 0;
 216         event* e = NULL;
 217
 218         immediate_control();
 219
 220         while(remaining > 0){
 221                 e = seq_advance(remaining, &used);
 222                 generate(left+i, right+i, used);
 223                 control(e);
 224                 i += used;
 225                 remaining -= used;
 226                 if(e == NULL && used == 0){
 227                         error_msg("synth: sequencer failed to advance or provide a control event.");
 228                         break;
 229                 }
 230         };
 231 }
 232
 233
 234 void synth_init(){
 235         int i;
 236         printf("  synth: ... ");
 237
 238         for(i=0; i<16; i++){
 239                 channels[i] = make_dummy_channel();
 240         }
 241
 242         //channels[0] = make_channel_from_instrument(ORG_KARPLUS);
 243         //channels[1] = make_channel_from_instrument(ORG_KARPLUS);
 244         //channels[2] = make_channel_from_instrument(ORG_KARPLUS);
 245         //channels[3] = make_channel_from_instrument(ORG_KARPLUS);
 246         channels[0] = make_channel_from_instrument(ORG_DEFAULT);
 247         channels[1] = make_channel_from_instrument(ORG_DEFAULT);
 248         channels[2] = make_channel_from_instrument(ORG_DEFAULT);
 249         channels[3] = make_channel_from_instrument(ORG_DEFAULT);
 250
 251
 252         //srate = sample_rate;
 253
 254         printf("OK\n");
 255 }