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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 DSP {
- // 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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