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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* Copyright (c) 2021, kleines Filmröllchen <filmroellchen@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/Types.h>
#include <AK/Variant.h>
#include <AK/Vector.h>
#include <LibAudio/Buffer.h>
#include <LibDSP/Envelope.h>
namespace LibDSP {
// FIXME: Audio::Frame is 64-bit float, which is quite large for long clips.
using Sample = Audio::Sample;
Sample const SAMPLE_OFF = { 0.0, 0.0 };
struct RollNote {
constexpr u32 length() const { return (off_sample - on_sample) + 1; }
u32 on_sample;
u32 off_sample;
u8 pitch;
i8 velocity;
Envelope to_envelope(u32 time, u32 attack_samples, u32 decay_samples, u32 release_samples)
{
i64 time_since_end = static_cast<i64>(time) - static_cast<i64>(off_sample);
// We're before the end of this note.
if (time_since_end < 0) {
i64 time_since_start = static_cast<i64>(time) - static_cast<i64>(on_sample);
if (time_since_start < 0)
return {};
if (time_since_start < attack_samples) {
if (attack_samples == 0)
return Envelope::from_attack(0);
return Envelope::from_attack(static_cast<double>(time_since_start) / static_cast<double>(attack_samples));
}
if (time_since_start < attack_samples + decay_samples) {
if (decay_samples == 0)
return Envelope::from_decay(0);
return Envelope::from_decay(static_cast<double>(time_since_start - attack_samples) / static_cast<double>(decay_samples));
}
// This is a note-dependent value!
u32 sustain_samples = length() - attack_samples - decay_samples;
return Envelope::from_sustain(static_cast<double>(time_since_start - attack_samples - decay_samples) / static_cast<double>(sustain_samples));
}
// Overshot the release time
if (time_since_end > release_samples)
return {};
return Envelope::from_release(static_cast<double>(time_since_end) / static_cast<double>(release_samples));
}
constexpr bool is_playing(u32 time) { return on_sample <= time && time <= off_sample; }
};
enum class SignalType : u8 {
Invalid,
Sample,
Note
};
using RollNotes = OrderedHashMap<u8, RollNote>;
struct Signal : public Variant<Sample, RollNotes> {
using Variant::Variant;
ALWAYS_INLINE SignalType type() const
{
if (has<Sample>())
return SignalType::Sample;
if (has<RollNotes>())
return SignalType::Note;
return SignalType::Invalid;
}
};
// Equal temperament, A = 440Hz
// We calculate note frequencies relative to A4:
// 440.0 * pow(pow(2.0, 1.0 / 12.0), N)
// Where N is the note distance from A.
constexpr double note_frequencies[] = {
// Octave 1
32.703195662574764,
34.647828872108946,
36.708095989675876,
38.890872965260044,
41.203444614108669,
43.653528929125407,
46.249302838954222,
48.99942949771858,
51.913087197493056,
54.999999999999915,
58.270470189761156,
61.735412657015416,
// Octave 2
65.406391325149571,
69.295657744217934,
73.416191979351794,
77.781745930520117,
82.406889228217381,
87.307057858250872,
92.4986056779085,
97.998858995437217,
103.82617439498618,
109.99999999999989,
116.54094037952237,
123.4708253140309,
// Octave 3
130.8127826502992,
138.59131548843592,
146.83238395870364,
155.56349186104035,
164.81377845643485,
174.61411571650183,
184.99721135581709,
195.99771799087452,
207.65234878997245,
219.99999999999989,
233.08188075904488,
246.94165062806198,
// Octave 4
261.62556530059851,
277.18263097687202,
293.66476791740746,
311.12698372208081,
329.62755691286986,
349.22823143300383,
369.99442271163434,
391.99543598174927,
415.30469757994513,
440,
466.16376151808993,
493.88330125612413,
// Octave 5
523.25113060119736,
554.36526195374427,
587.32953583481526,
622.25396744416196,
659.25511382574007,
698.456462866008,
739.98884542326903,
783.99087196349899,
830.60939515989071,
880.00000000000034,
932.32752303618031,
987.76660251224882,
// Octave 6
1046.5022612023952,
1108.7305239074892,
1174.659071669631,
1244.5079348883246,
1318.5102276514808,
1396.9129257320169,
1479.977690846539,
1567.9817439269987,
1661.2187903197821,
1760.000000000002,
1864.6550460723618,
1975.5332050244986,
// Octave 7
2093.0045224047913,
2217.4610478149793,
2349.3181433392633,
2489.0158697766506,
2637.020455302963,
2793.8258514640347,
2959.9553816930793,
3135.9634878539991,
3322.437580639566,
3520.0000000000055,
3729.3100921447249,
3951.0664100489994,
};
constexpr size_t note_count = array_size(note_frequencies);
constexpr double middle_c = note_frequencies[36];
}
|
