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/*
* Copyright (c) 2021, kleines Filmröllchen <filmroellchen@serenityos.org>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/StdLibExtras.h>
namespace LibDSP {
// For now, this cannot be optimal as clang doesn't know underlying type specifications.
enum EnvelopeState {
Off,
Attack,
Decay,
Sustain,
Release,
};
struct Envelope {
constexpr Envelope() = default;
constexpr Envelope(double envelope)
: envelope(envelope)
{
}
constexpr bool is_attack() const { return 0 <= envelope && envelope < 1; }
constexpr double attack() const { return clamp(envelope, 0, 1); }
constexpr void set_attack(double offset) { envelope = offset; }
static constexpr Envelope from_attack(double attack) { return Envelope(attack); }
constexpr bool is_decay() const { return 1 <= envelope && envelope < 2; }
constexpr double decay() const { return clamp(envelope, 1, 2) - 1; }
constexpr void set_decay(double offset) { envelope = 1 + offset; }
static constexpr Envelope from_decay(double decay) { return Envelope(decay + 1); }
constexpr bool is_sustain() const { return 2 <= envelope && envelope < 3; }
constexpr double sustain() const { return clamp(envelope, 2, 3) - 2; }
constexpr void set_sustain(double offset) { envelope = 2 + offset; }
static constexpr Envelope from_sustain(double decay) { return Envelope(decay + 2); }
constexpr bool is_release() const { return 3 <= envelope && envelope < 4; }
constexpr double release() const { return clamp(envelope, 3, 4) - 3; }
constexpr void set_release(double offset) { envelope = 3 + offset; }
static constexpr Envelope from_release(double decay) { return Envelope(decay + 3); }
constexpr bool is_active() const { return 0 <= envelope && envelope < 4; }
constexpr void reset() { envelope = -1; }
constexpr operator EnvelopeState() const
{
if (!is_active())
return EnvelopeState::Off;
if (is_attack())
return EnvelopeState::Attack;
if (is_decay())
return EnvelopeState::Decay;
if (is_sustain())
return EnvelopeState::Sustain;
if (is_release())
return EnvelopeState::Release;
VERIFY_NOT_REACHED();
}
double envelope { -1 };
};
}
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