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 "effect.h"
  31
  32 /*******************
  33         Data
  34 ********************/
  35
  36 /*******************
  37         Code
  38 ********************/
  39
  40 void init_delay(struct effect_delay * e, int size, double vol)
  41 {
  42         e->lbuffer=(int *) malloc(size * sizeof(int));
  43         memset(e->lbuffer, '\0', size * sizeof(int));
  44         e->rbuffer=(int *) malloc(size * sizeof(int));
  45         memset(e->rbuffer, '\0', size * sizeof(int));
  46
  47         e->size=size;
  48         e->vol=vol;
  49         e->cursor=0;
  50 }
  51
  52
  53 void process_delay(struct effect_delay * e, int * lsample, int * rsample)
  54 {
  55         int l,r;
  56
  57         l=e->lbuffer[e->cursor];
  58         r=e->lbuffer[e->cursor];
  59
  60         l=*lsample + (int)(e->vol * (double)l);
  61         r=*rsample + (int)(e->vol * (double)r);
  62
  63         e->lbuffer[e->cursor]=*lsample;
  64         e->rbuffer[e->cursor]=*rsample;
  65
  66         if(++e->cursor == e->size) e->cursor=0;
  67
  68         *lsample=l;
  69         *rsample=r;
  70 }
  71
  72
  73 void process_reverb(struct effect_delay * e, int * lsample, int * rsample)
  74 {
  75         int l,r;
  76
  77         l=e->lbuffer[e->cursor];
  78         r=e->lbuffer[e->cursor];
  79
  80         e->lbuffer[e->cursor]=*lsample + (int)(e->vol * (double)l);
  81         e->rbuffer[e->cursor]=*rsample + (int)(e->vol * (double)r);
  82
  83         l+=*lsample;
  84         r+=*rsample;
  85
  86         if(++e->cursor == e->size) e->cursor=0;
  87
  88         *lsample=l;
  89         *rsample=r;
  90 }
  91
  92
  93 void process_flanger(struct effect_delay * e, int * lsample, int * rsample)
  94 {
  95         int l,r;
  96         double c;
  97
  98         c=(double) (e->cursor / 2);
  99         c+=c * sin((c * 6.28) / (double) e->size);
 100
 101         e->lbuffer[e->cursor]=*lsample;
 102         e->rbuffer[e->cursor]=*rsample;
 103
 104         if(++e->cursor == e->size) e->cursor=0;
 105
 106         *lsample=l;
 107         *rsample=r;
 108 }