1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
/*
Copyright (C) 2000 Stefan Westerfeld
stefan@space.twc.de
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
#include "artsmodulessynth.h"
#include "debug.h"
#include "stdsynthmodule.h"
using namespace Arts;
class Synth_ENVELOPE_ADSR_impl : virtual public Synth_ENVELOPE_ADSR_skel,
virtual public StdSynthModule
{
protected:
enum { NOOUT, ATTACK, SUSTAIN, DECAY, RELEASE } currentphase;
float level,increment,decrement;
public:
void streamInit()
{
currentphase = NOOUT;
level = 0;
}
void calculateBlock(unsigned long samples);
};
void Synth_ENVELOPE_ADSR_impl::calculateBlock(unsigned long samples)
{
/* FIXME:
* should be rewritten as generic envelope, would certainly
* be faster & more flexible
*/
unsigned long i;
for(i=0;i<samples;i++)
{
done[i] = 0;
if(active[i] < 0.5)
{
if(currentphase == NOOUT)
{
level = 0;
done[i] = 1;
}
else
{
if(currentphase != RELEASE) {
artsdebug("ADSR: entering release phase\n");
currentphase = RELEASE;
decrement = level / (release[i] * samplingRateFloat);
}
level -= decrement;
if(level <= 0)
{
level = 0;
currentphase = NOOUT;
}
}
}
else
{
switch(currentphase)
{
//quickly kill the note that is still there (channel busy ;)
case RELEASE:
level -= 1/200;
if(level <= 0) {
currentphase = NOOUT;
level = 0;
}
break;
case NOOUT:
artsdebug("ADSR: entering attack\n");
increment = 1 / (attack[i] * samplingRateFloat);
currentphase = ATTACK;
break;
case ATTACK:
level += increment;
if (level >= 1)
{
level = 1;
currentphase = DECAY;
decrement = (1-sustain[i]) /
(decay[i] * samplingRateFloat);
}
break;
case DECAY:
level -= decrement;
if (level <= sustain[i])
{
level = sustain[i];
currentphase = SUSTAIN;
}
break;
case SUSTAIN:
level = sustain[i];
break;
}
}
outvalue[i] = invalue[i] * level;
}
}
REGISTER_IMPLEMENTATION(Synth_ENVELOPE_ADSR_impl);
|
