Classic ADSR envelope generator with exponential curves. More...

#include <EnvelopeGenerator.h>

Public Types
enum class	State { Idle , Attack , Decay , Sustain , Release }

Public Member Functions
	ADSREnvelope () noexcept

void	prepare (double sampleRate) noexcept
	Prepares the envelope for the given sample rate.

void	prepare (const AudioSpec &spec) noexcept
	Prepares from AudioSpec (unified API).

void	setAttack (T ms) noexcept
	Sets attack time in milliseconds (0 -> 1).

void	setDecay (T ms) noexcept
	Sets decay time in milliseconds (1 -> sustain).

void	setSustain (T level) noexcept
	Sets sustain level (0.0 to 1.0).

void	setRelease (T ms) noexcept
	Sets release time in milliseconds (full scale -> silence).

void	setParameters (T attackMs, T decayMs, T sustain, T releaseMs) noexcept
	Sets all ADSR parameters at once.

void	setCurvature (T curve) noexcept
	Sets the curvature of all exponential stages at once.

void	setCurvature (T attackCurve, T decayCurve, T releaseCurve) noexcept
	Sets independent curvatures per stage.

void	noteOn () noexcept
	Triggers the attack phase (note on). Legato: continues from the current value.

void	noteOff () noexcept
	Triggers the release phase (note off).

void	reset () noexcept
	Resets the envelope to idle with zero output.

T	getNextValue () noexcept
	Returns the next envelope value and advances the state machine.

void	processBlock (T *output, int numSamples) noexcept
	Fills a buffer with envelope values.

T	getCurrentValue () const noexcept
	Returns the current envelope value.

State	getState () const noexcept
	Returns the current state.

bool	isActive () const noexcept
	Returns true if the envelope is actively producing output.

Detailed Description

template<FloatType T>
class dspark::ADSREnvelope< T >

Classic ADSR envelope generator with exponential curves.

Each stage runs an asymptotic RC-style one-pole toward a target that overshoots the stage endpoint, so the stage completes in finite time with the exact duration set by its parameter:

Attack: 0 -> 1 in attackMs (from a retrigger it starts at the current value and arrives earlier, click-free legato).
Decay: 1 -> sustain in decayMs for any sustain level (the overshoot scales with the stage depth, matching the self-similar RC discharge).
Release: calibrated for full scale -> silence in releaseMs. Like an analog RC release (fixed dB-per-second slope), releasing from a lower sustain reaches silence proportionally sooner.

Curvature shapes each stage: high values are strongly exponential, 0.1 is near-linear. Stage durations stay exact across the whole curvature range.

State machine: Idle -> Attack -> Decay -> Sustain -> Release -> Idle. The recursion state is double regardless of T (the framework rule for recursive state): in float, very long stages stall short of their target when the per-sample increment rounds to zero.

Threading is owner-managed: call setters, triggers and processing from the owning (audio) thread, the pattern of a synth voice. A default-constructed envelope is functional at 48 kHz; prepare() adapts it to the real rate.

Template Parameters

T	Output type (float or double). Constrained to IEEE 754 floats.

Definition at line 56 of file EnvelopeGenerator.h.

Member Enumeration Documentation

◆ State

template<FloatType T>

enum class dspark::ADSREnvelope::State

strong

Enumerator
Idle
Attack
Decay
Sustain
Release

Definition at line 59 of file EnvelopeGenerator.h.

Constructor & Destructor Documentation

◆ ADSREnvelope()

template<FloatType T>

dspark::ADSREnvelope< T >::ADSREnvelope ( )

inlinenoexcept

Definition at line 61 of file EnvelopeGenerator.h.

Member Function Documentation

◆ getCurrentValue()

template<FloatType T>

T dspark::ADSREnvelope< T >::getCurrentValue ( ) const

inlinenoexcept

Returns the current envelope value.

Definition at line 328 of file EnvelopeGenerator.h.

◆ getNextValue()

template<FloatType T>

T dspark::ADSREnvelope< T >::getNextValue ( )

inlinenoexcept

Returns the next envelope value and advances the state machine.

Returns: Envelope value in [0, 1].

Definition at line 167 of file EnvelopeGenerator.h.

◆ getState()

template<FloatType T>

State dspark::ADSREnvelope< T >::getState ( ) const

inlinenoexcept

Returns the current state.

Definition at line 331 of file EnvelopeGenerator.h.

◆ isActive()

template<FloatType T>

bool dspark::ADSREnvelope< T >::isActive ( ) const

inlinenoexcept

Returns true if the envelope is actively producing output.

Definition at line 334 of file EnvelopeGenerator.h.

◆ noteOff()

template<FloatType T>

void dspark::ADSREnvelope< T >::noteOff ( )

inlinenoexcept

Triggers the release phase (note off).

Definition at line 148 of file EnvelopeGenerator.h.

◆ noteOn()

template<FloatType T>

void dspark::ADSREnvelope< T >::noteOn ( )

inlinenoexcept

Triggers the attack phase (note on). Legato: continues from the current value.

Definition at line 142 of file EnvelopeGenerator.h.

◆ prepare() [1/2]

template<FloatType T>

void dspark::ADSREnvelope< T >::prepare ( const AudioSpec & spec )

inlinenoexcept

Prepares from AudioSpec (unified API).

Parameters

spec	Audio specification containing the sample rate.

Definition at line 78 of file EnvelopeGenerator.h.

◆ prepare() [2/2]

template<FloatType T>

void dspark::ADSREnvelope< T >::prepare ( double sampleRate )

inlinenoexcept

Prepares the envelope for the given sample rate.

Parameters

sampleRate The operating sample rate in Hz.

Definition at line 67 of file EnvelopeGenerator.h.

◆ processBlock()

template<FloatType T>

void dspark::ADSREnvelope< T >::processBlock	(	T *	output,
		int	numSamples
	)

inlinenoexcept

Fills a buffer with envelope values.

Runs each stage as a tight loop with its constants hoisted (no state dispatch per sample). Sample-exact match with getNextValue().

Parameters

output	Buffer to fill with envelope values.
numSamples	Number of samples to generate.

Definition at line 227 of file EnvelopeGenerator.h.

◆ reset()

template<FloatType T>

void dspark::ADSREnvelope< T >::reset ( )

inlinenoexcept

Resets the envelope to idle with zero output.

Definition at line 155 of file EnvelopeGenerator.h.

◆ setAttack()

template<FloatType T>

void dspark::ADSREnvelope< T >::setAttack ( T ms )

inlinenoexcept

Sets attack time in milliseconds (0 -> 1).

Definition at line 83 of file EnvelopeGenerator.h.

◆ setCurvature() [1/2]

template<FloatType T>

void dspark::ADSREnvelope< T >::setCurvature	(	T	attackCurve,
		T	decayCurve,
		T	releaseCurve
	)

inlinenoexcept

Sets independent curvatures per stage.

Classic analog envelopes shape each stage differently (near-linear attack, strongly exponential release). Higher values = more curved.

Parameters

attackCurve	Attack curvature (0.1 to 10.0; low = near-linear).
decayCurve	Decay curvature.
releaseCurve	Release curvature.

Definition at line 131 of file EnvelopeGenerator.h.

◆ setCurvature() [2/2]

template<FloatType T>

void dspark::ADSREnvelope< T >::setCurvature ( T curve )

inlinenoexcept

Sets the curvature of all exponential stages at once.

Parameters

curve Curvature factor (default: 3.0, range: 0.1 to 10.0).

Definition at line 114 of file EnvelopeGenerator.h.

◆ setDecay()

template<FloatType T>

void dspark::ADSREnvelope< T >::setDecay ( T ms )

inlinenoexcept

Sets decay time in milliseconds (1 -> sustain).

Definition at line 86 of file EnvelopeGenerator.h.

◆ setParameters()

template<FloatType T>

void dspark::ADSREnvelope< T >::setParameters	(	T	attackMs,
		T	decayMs,
		T	sustain,
		T	releaseMs
	)

inlinenoexcept

Sets all ADSR parameters at once.

Parameters

attackMs	Attack time in ms.
decayMs	Decay time in ms.
sustain	Sustain level (0-1).
releaseMs	Release time in ms.

Definition at line 101 of file EnvelopeGenerator.h.

◆ setRelease()

template<FloatType T>

void dspark::ADSREnvelope< T >::setRelease ( T ms )

inlinenoexcept

Sets release time in milliseconds (full scale -> silence).

Definition at line 92 of file EnvelopeGenerator.h.

◆ setSustain()

template<FloatType T>

void dspark::ADSREnvelope< T >::setSustain ( T level )

inlinenoexcept

Sets sustain level (0.0 to 1.0).

Definition at line 89 of file EnvelopeGenerator.h.

The documentation for this class was generated from the following file:

Core/EnvelopeGenerator.h

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ State

Constructor & Destructor Documentation

◆ ADSREnvelope()

Member Function Documentation

◆ getCurrentValue()

◆ getNextValue()

◆ getState()

◆ isActive()

◆ noteOff()

◆ noteOn()

◆ prepare() [1/2]

◆ prepare() [2/2]

◆ processBlock()

◆ reset()

◆ setAttack()

◆ setCurvature() [1/2]

◆ setCurvature() [2/2]

◆ setDecay()

◆ setParameters()

◆ setRelease()

◆ setSustain()