mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 02:12:45 +00:00
a749b16674
LibDSP is a library for digital signal processing, and is primarily intended to support the future DAW version of Piano.
146 lines
3.3 KiB
C++
146 lines
3.3 KiB
C++
/*
|
|
* Copyright (c) 2021, kleines Filmröllchen <malu.bertsch@gmail.com>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Types.h>
|
|
#include <AK/Variant.h>
|
|
#include <AK/Vector.h>
|
|
#include <LibAudio/Buffer.h>
|
|
|
|
namespace LibDSP {
|
|
|
|
// FIXME: Audio::Frame is 64-bit float, which is quite large for long clips.
|
|
using Sample = Audio::Frame;
|
|
|
|
Sample const SAMPLE_OFF = { 0.0, 0.0 };
|
|
|
|
struct RollNote {
|
|
u32 length() const { return (off_sample - on_sample) + 1; }
|
|
|
|
u32 on_sample;
|
|
u32 off_sample;
|
|
u8 pitch;
|
|
i8 velocity;
|
|
};
|
|
|
|
enum class SignalType : u8 {
|
|
Invalid,
|
|
Sample,
|
|
Note
|
|
};
|
|
|
|
struct Signal : public Variant<Sample, Vector<RollNote>> {
|
|
using Variant::Variant;
|
|
ALWAYS_INLINE SignalType type() const
|
|
{
|
|
return has<Sample>() ? SignalType::Sample : has<Vector<RollNote>>() ? SignalType::Note
|
|
: 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];
|
|
|
|
}
|