libs/ardour/mtdm.cc

   1 /*
   2     Copyright (C) 2003-2008 Fons Adriaensen <fons@kokkinizita.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 #include "ardour/mtdm.h"
  20
  21 MTDM::MTDM (void)
  22         : _cnt (0)
  23         , _inv (0)
  24 {
  25         int   i;
  26         Freq  *F;
  27
  28         _freq [0].f = 4096;
  29         _freq [1].f =  512;
  30         _freq [2].f = 1088;
  31         _freq [3].f = 1544;
  32         _freq [4].f = 2049;
  33
  34         _freq [0].a = 0.2f;
  35         _freq [1].a = 0.1f;
  36         _freq [2].a = 0.1f;
  37         _freq [3].a = 0.1f;
  38         _freq [4].a = 0.1f;
  39
  40         for (i = 0, F = _freq; i < 5; i++, F++) {
  41                 F->p = 128;
  42                 F->xa = F->ya = 0.0f;
  43                 F->xf = F->yf = 0.0f;
  44         }
  45 }
  46
  47 int
  48 MTDM::process (size_t len, float *ip, float *op)
  49 {
  50         int    i;
  51         float  vip, vop, a, c, s;
  52         Freq   *F;
  53
  54         while (len--)
  55         {
  56                 vop = 0.0f;
  57                 vip = *ip++;
  58                 for (i = 0, F = _freq; i < 5; i++, F++)
  59                 {
  60                         a = 2 * (float) M_PI * (F->p & 65535) / 65536.0;
  61                         F->p += F->f;
  62                         c =  cosf (a);
  63                         s = -sinf (a);
  64                         vop += F->a * s;
  65                         F->xa += s * vip;
  66                         F->ya += c * vip;
  67                 }
  68                 *op++ = vop;
  69                 if (++_cnt == 16)
  70                 {
  71                         for (i = 0, F = _freq; i < 5; i++, F++)
  72                         {
  73                                 F->xf += 1e-3f * (F->xa - F->xf + 1e-20);
  74                                 F->yf += 1e-3f * (F->ya - F->yf + 1e-20);
  75                                 F->xa = F->ya = 0.0f;
  76                         }
  77                         _cnt = 0;
  78                 }
  79         }
  80
  81         return 0;
  82 }
  83
  84 int
  85 MTDM::resolve ()
  86 {
  87         int     i, k, m;
  88         double  d, e, f0, p;
  89         Freq    *F = _freq;
  90
  91         if (hypot (F->xf, F->yf) < 0.01) {
  92                 return -1;
  93         }
  94
  95         d = atan2 (F->yf, F->xf) / (2 * M_PI);
  96
  97         if (_inv) {
  98                 d += 0.5f;
  99         }
 100
 101         if (d > 0.5f) {
 102                 d -= 1.0f;
 103         }
 104
 105         f0 = _freq [0].f;
 106         m = 1;
 107         _err = 0.0;
 108
 109         for (i = 0; i < 4; i++) {
 110                 F++;
 111                 p = atan2 (F->yf, F->xf) / (2 * M_PI) - d * F->f / f0;
 112                 if (_inv) {
 113                         p += 0.5f;
 114                 }
 115                 p -= floor (p);
 116                 p *= 8;
 117                 k = (int)(floor (p + 0.5));
 118                 e = fabs (p - k);
 119                 if (e > _err) {
 120                         _err = e;
 121                 }
 122                 if (e > 0.4) {
 123                         return 1;
 124                 }
 125                 d += m * (k & 7);
 126                 m *= 8;
 127         }
 128
 129         _del = 16 * d;
 130
 131         return 0;
 132 }