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/*
* Copyright (c) 2021, kleines Filmröllchen <filmroellchen@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FixedArray.h>
#include <AK/HashMap.h>
#include <AK/Noncopyable.h>
#include <AK/Types.h>
#include <AK/Variant.h>
#include <AK/Vector.h>
#include <LibAudio/Sample.h>
#include <LibDSP/Envelope.h>
namespace DSP {
using Sample = Audio::Sample;
constexpr 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;
constexpr Envelope to_envelope(u32 time, u32 attack_samples, u32 decay_samples, u32 release_samples) const
{
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) const { return on_sample <= time && time <= off_sample; }
constexpr bool is_playing_during(u32 start_time, u32 end_time) const
{
// There are three scenarios for a playing note.
return
// 1. The note ends within our time frame.
(this->off_sample >= start_time && this->off_sample < end_time)
// 2. The note starts within our time frame.
|| (this->on_sample >= start_time && this->on_sample < end_time)
// 3. The note starts before our time frame and ends after it.
|| (this->on_sample < start_time && this->off_sample >= end_time);
}
constexpr bool overlaps_with(RollNote const& other) const
{
// Notes don't overlap if one is completely before or behind the other.
return !((this->on_sample < other.on_sample && this->off_sample < other.on_sample)
|| (this->on_sample >= other.off_sample && this->off_sample >= other.off_sample));
}
};
enum class SignalType : u8 {
Invalid,
Sample,
Note
};
// Perfect hashing for note (MIDI) values. This just uses the note value as the hash itself.
class PerfectNoteHashTraits : Traits<u8> {
public:
static constexpr bool equals(u8 const& a, u8 const& b) { return a == b; }
static constexpr unsigned hash(u8 value)
{
return static_cast<unsigned>(value);
}
};
// 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 Array<double, 84> 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,
};
using RollNotes = Array<Optional<RollNote>, note_frequencies.size()>;
constexpr size_t const notes_per_octave = 12;
constexpr double const middle_c = note_frequencies[36];
struct Signal : public Variant<FixedArray<Sample>, RollNotes> {
using Variant::Variant;
AK_MAKE_NONCOPYABLE(Signal);
public:
Signal& operator=(Signal&&) = default;
Signal(Signal&&) = default;
ALWAYS_INLINE SignalType type() const
{
if (has<FixedArray<Sample>>())
return SignalType::Sample;
if (has<RollNotes>())
return SignalType::Note;
return SignalType::Invalid;
}
};
}
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