portamento.h

   1 /* -*- Mode: C ; c-basic-offset: 2 -*- */
   2 /*****************************************************************************
   3  *
   4  *   Copyright (C) 2006,2007,2008,2009 Nedko Arnaudov <nedko@arnaudov.name>
   5  *   Copyright (C) 2002-2005 Nasca Octavian Paul
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; version 2 of the License
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  *****************************************************************************/
  21
  22 #ifndef PORTAMENTO_H__83CC72B6_3F89_4791_ACEF_098A31CB368A__INCLUDED
  23 #define PORTAMENTO_H__83CC72B6_3F89_4791_ACEF_098A31CB368A__INCLUDED
  24
  25 struct zyn_portamento
  26 {
  27   bool enabled;                 // whether portamento is enabled
  28
  29   float time;
  30
  31   // the threshold of enabling protamento
  32   // Minimum or max. difference of the notes in order to do the portamento (x 100 cents)
  33   float pitch_threshold;
  34
  35   // whether to enable the portamento only below (false) or above (true) the threshold
  36   bool pitch_threshold_above;
  37
  38   // 'up portanemto' means when the frequency is rising (eg: the portamento is from 200Hz to 300 Hz)
  39   // 'down portanemto' means when the frequency is lowering (eg: the portamento is from 300Hz to 200 Hz)
  40
  41   // Portamento time stretch (up/down)
  42   // this value represent how the portamento time is reduced
  43   // -1.0 - for down portamento
  44   // (-1.0,0) - the up portamento's time is smaller than the down portamento
  45   // 0 - the portamento time is always the same
  46   // (0,1.0) - the down portamento's time is smaller than the up portamento
  47   // 1.0 - for upper portamento
  48   float up_down_time_stretch;
  49
  50   // this value is used to compute the actual portamento
  51   float freqrap;
  52
  53   // whether portamento is used by a note
  54   bool used;
  55
  56   // x is from 0.0 (start portamento) to 1.0 (finished portamento)
  57   float x;
  58
  59   // dx is x increment
  60   float dx;
  61
  62   // this is used for computing oldfreq value from x
  63   float origfreqrap;
  64 };
  65
  66 #ifdef __cplusplus
  67 extern "C" {
  68 #endif
  69 #if 0
  70 } /* Adjust editor indent */
  71 #endif
  72
  73 void
  74 zyn_portamento_init(
  75   struct zyn_portamento * portamento_ptr);
  76
  77 // returns true if the portamento's conditions are true, else returns false
  78 bool
  79 zyn_portamento_start(
  80   float sample_rate,
  81   struct zyn_portamento * portamento_ptr,
  82   float oldfreq,
  83   float newfreq);
  84
  85 // update portamento values
  86 void
  87 zyn_portamento_update(
  88   struct zyn_portamento * portamento_ptr);
  89
  90 #if 0
  91 { /* Adjust editor indent */
  92 #endif
  93 #ifdef __cplusplus
  94 } /* extern "C" */
  95 #endif
  96
  97 #endif /* #ifndef PORTAMENTO_H__83CC72B6_3F89_4791_ACEF_098A31CB368A__INCLUDED */