1 /* FluidSynth - A Software Synthesizer
2 *
3 * Copyright (C) 2003 Peter Hanappe and others.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public License
7 * as published by the Free Software Foundation; either version 2 of
8 * the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the Free
17 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA
19 */
20
21 #ifndef _FLUID_LFO_H
22 #define _FLUID_LFO_H
23
24 #include "fluidsynth_priv.h"
25
26 typedef struct _fluid_lfo_t fluid_lfo_t;
27
28 struct _fluid_lfo_t {
29 fluid_real_t val; /* the current value of the LFO */
30 unsigned int delay; /* the delay of the lfo in samples */
31 fluid_real_t increment; /* the lfo frequency is converted to a per-buffer increment */
32 };
33
34 static inline void
fluid_lfo_reset(fluid_lfo_t * lfo)35 fluid_lfo_reset(fluid_lfo_t* lfo)
36 {
37 lfo->val = 0.0f;
38 }
39
40 // These two cannot be inlined since they're used by event_dispatch
41 void fluid_lfo_set_incr(fluid_lfo_t* lfo, fluid_real_t increment);
42 void fluid_lfo_set_delay(fluid_lfo_t* lfo, unsigned int delay);
43
44 static inline fluid_real_t
fluid_lfo_get_val(fluid_lfo_t * lfo)45 fluid_lfo_get_val(fluid_lfo_t* lfo)
46 {
47 return lfo->val;
48 }
49
50 static inline void
fluid_lfo_calc(fluid_lfo_t * lfo,unsigned int cur_delay)51 fluid_lfo_calc(fluid_lfo_t* lfo, unsigned int cur_delay)
52 {
53 if (cur_delay < lfo->delay)
54 return;
55
56 lfo->val += lfo->increment;
57
58 if (lfo->val > (fluid_real_t) 1.0)
59 {
60 lfo->increment = -lfo->increment;
61 lfo->val = (fluid_real_t) 2.0 - lfo->val;
62 }
63 else if (lfo->val < (fluid_real_t) -1.0)
64 {
65 lfo->increment = -lfo->increment;
66 lfo->val = (fluid_real_t) -2.0 - lfo->val;
67 }
68
69 }
70
71 #endif
72
73