blob: ed9ead738e91f3d936306c7c24fd2d9f45453637 (
plain)
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
|
/*
* Copyright 2009 Phil Burk, Mobileer Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.jsyn.unitgen;
import com.jsyn.ports.UnitInputPort;
/**
* Wave Folder
*
* Fold the input waveform by passing it through a sine function
* and output the results in the range of -1.0 to 1.0.
*
* This works best if the amplitude of the input waveform is close to 1.0.
*
* @author Phil Burk (C) 2020 Mobileer Inc
*/
public class WaveFolder extends UnitFilter
{
/**
* The depth of the wave-folding effect.
* At zero there should be no audible effect.
*/
public UnitInputPort amount;
private static final double MAX_SCALE = 8.0;
/* Define Unit Ports used by connect() and set(). */
public WaveFolder() {
addPort(amount = new UnitInputPort("Amount"));
amount.setup(0.0, 0.0, MAX_SCALE);
}
@Override
public void generate( int start, int limit )
{
double[] inputs = input.getValues();
double[] scales = amount.getValues();
double[] outputs = output.getValues();
for (int i = start; i < limit; i++) {
double inputValue = inputs[i];
double scaleValue = scales[i];
// Prevent blowup near zero.
scaleValue = Math.max(scaleValue, 0.00001);
double phase = inputValue * scaleValue;
double folded;
// if (true) {
// Clip to -1/+1 range for fastSin even for extreme ranges.
phase = (phase + 256.0 + 1.0) * 0.5;
phase -= Math.floor(phase);
phase = (phase * 2.0) - 1.0;
// Fold using a sine function that ranges -1 to +1.
folded = SineOscillator.fastSin(phase);
// } else {
// folded = Math.sin(phase * Math.PI); // slow
// }
// Try to maintain constant amplitude at small scale value.
// Based on sin(x) ~= x for low values of x.
if (scaleValue < 1.0) {
folded /= scaleValue * (((1 - Math.PI) * scaleValue) + Math.PI);
}
outputs[i] = folded;
}
}
}
|
