effect.c

   1 /*
   2
   3     PROGRAM_NAME PROGRAM_VERSION - PROGRAM_DESCRIPTION
   4
   5     Copyright (C) 2003 Angel Ortega <angel@triptico.com>
   6
   7     This program is free software; you can redistribute it and/or
   8     modify it under the terms of the GNU General Public License
   9     as published by the Free Software Foundation; either version 2
  10     of the License, or (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20
  21     http://www.triptico.com
  22
  23 */
  24
  25 #include "config.h"
  26
  27 #include <stdlib.h>
  28 #include <math.h>
  29
  30 #include "core.h"
  31 #include "effect.h"
  32
  33 /*******************
  34         Data
  35 ********************/
  36
  37 /*******************
  38         Code
  39 ********************/
  40
  41 void init_delay(struct effect_delay * e, int size, double gain)
  42 {
  43         e->lbuffer=(int *) malloc(size * sizeof(int));
  44         memset(e->lbuffer, '\0', size * sizeof(int));
  45         e->rbuffer=(int *) malloc(size * sizeof(int));
  46         memset(e->rbuffer, '\0', size * sizeof(int));
  47
  48         e->size=size;
  49         e->gain=gain;
  50         e->cursor=0;
  51 }
  52
  53
  54 void process_delay(struct effect_delay * e, int * lsample, int * rsample)
  55 {
  56         int l,r;
  57
  58         l=e->lbuffer[e->cursor];
  59         r=e->lbuffer[e->cursor];
  60
  61         l=*lsample + (int)(e->gain * (double)l);
  62         r=*rsample + (int)(e->gain * (double)r);
  63
  64         e->lbuffer[e->cursor]=*lsample;
  65         e->rbuffer[e->cursor]=*rsample;
  66
  67         if(++e->cursor == e->size) e->cursor=0;
  68
  69         *lsample=l;
  70         *rsample=r;
  71 }
  72
  73
  74 void process_comb(struct effect_delay * e, int * lsample, int * rsample)
  75 {
  76         int l,r;
  77
  78         l=e->lbuffer[e->cursor];
  79         r=e->lbuffer[e->cursor];
  80
  81         e->lbuffer[e->cursor]=*lsample + (int)(e->gain * (double)l);
  82         e->rbuffer[e->cursor]=*rsample + (int)(e->gain * (double)r);
  83
  84         l+=*lsample;
  85         r+=*rsample;
  86
  87         if(++e->cursor == e->size) e->cursor=0;
  88
  89         *lsample=l;
  90         *rsample=r;
  91 }
  92
  93
  94 double _depth=150;
  95 double _lfo=0;
  96
  97 double lfo(double f, double * p)
  98 {
  99         double i;
 100
 101         i=(f * 6.28) / (double) _frequency;
 102         *p+=i;
 103
 104         return(sin(*p));
 105 }
 106
 107
 108 void process_flanger(struct effect_delay * e, int * lsample, int * rsample)
 109 {
 110         int l,r;
 111         double c,s;
 112 /*
 113         s=(double) e->size;
 114         c=(double) e->cursor + (s / 2);
 115         c-=(s / 2) * sin((c * 6.28) / s);
 116         if(c > s) c-=s;
 117 */
 118         s=(double) e->size;
 119         c=(double) e->cursor;
 120         c-=_depth * lfo(0.1, &_lfo);
 121         if(c > s) c-=s;
 122
 123         l=get_sample(e->lbuffer, s, c);
 124         r=get_sample(e->rbuffer, s, c);
 125
 126         e->lbuffer[e->cursor]=*lsample;
 127         e->rbuffer[e->cursor]=*rsample;
 128
 129         if(++e->cursor == e->size) e->cursor=0;
 130
 131         *lsample+=l;
 132         *rsample+=r;
 133 }