dsp::adsr Class Reference

#include <envelope.h>

Public Types
enum	env_state {   STOP , ATTACK , DECAY , SUSTAIN ,   RELEASE , LOCKDECAY }

Public Member Functions
	adsr ()
void	reset ()
	Stop (reset) the envelope.
void	set (float a, float d, float s, float r, float er, float f=0.f)
bool	released () const
bool	stopped () const
void	note_on ()
	Start the envelope.
void	note_off ()
	Release the envelope.
void	advance ()
	Calculate next envelope value.
double	interpolate (double pos)
float	get_amp_value ()

Public Attributes
env_state	state
	Current envelope stage.
double	attack
double	decay
double	sustain
double	release
double	fade
double	release_time
	Requested release time (not the rate!) in frames, used for recalculating the rate if sustain is changed.
double	value
	Current envelope (output) level.
double	thisrelease
double	thiss
double	old_value
	Value from the time before advance() was called last time.

Detailed Description

Rate-based ADSFR envelope class. Note that if release rate is slower than decay rate, this envelope won't use release rate until output level falls below sustain level it's different to what certain hardware synth companies did, but it prevents the very un-musical (IMHO) behaviour known from (for example) SoundFont 2.

Member Enumeration Documentation

env_state

enum dsp::adsr::env_state

Enumerator
STOP	envelope is stopped
ATTACK	attack - rise from 0 to 1
DECAY	decay - fall from 1 to sustain level
SUSTAIN	sustain - remain at sustain level (unless sustain is 0 - then it gets stopped); with fade != 0 it goes towards 0% (positive fade) or 100% (negative fade)
RELEASE	release - fall from sustain (or pre-sustain) level to 0
LOCKDECAY	locked decay

Constructor & Destructor Documentation

adsr()

dsp::adsr::adsr ( )

inline

Member Function Documentation

advance()

void dsp::adsr::advance ( )

inline

Calculate next envelope value.

get_amp_value()

float dsp::adsr::get_amp_value ( )

inline

interpolate()

double dsp::adsr::interpolate ( double pos )

inline

Return a value between old_value (previous step) and value (current step)

Parameters

pos	between 0 and 1

note_off()

void dsp::adsr::note_off ( )

inline

Release the envelope.

note_on()

void dsp::adsr::note_on ( )

inline

Start the envelope.

released()

bool dsp::adsr::released ( ) const

inline

Return values

true	if envelope is in released state (forced decay, release or stopped)

reset()

void dsp::adsr::reset ( )

inline

Stop (reset) the envelope.

set()

void dsp::adsr::set ( float a, float d, float s, float r, float er, float f = 0.f )

inline

Set the envelope parameters (updates rate member variables based on values passed)

Parameters

a	attack time
d	decay time
s	sustain level
r	release time
er	Envelope (update) rate
f	fade time (if applicable)

stopped()

bool dsp::adsr::stopped ( ) const

inline

Return values

true	if envelope is stopped (has not been started or has run till its end)

Member Data Documentation

attack

double dsp::adsr::attack

Note

these are rates, not times

decay

double dsp::adsr::decay

fade

double dsp::adsr::fade

old_value

double dsp::adsr::old_value

Value from the time before advance() was called last time.

release

double dsp::adsr::release

release_time

double dsp::adsr::release_time

Requested release time (not the rate!) in frames, used for recalculating the rate if sustain is changed.

state

env_state dsp::adsr::state

Current envelope stage.

sustain

double dsp::adsr::sustain

thisrelease

double dsp::adsr::thisrelease

Release rate used for the current note (calculated from this note's sustain level, and not the current sustain level, which may have changed after note has been released)

thiss

double dsp::adsr::thiss

Sustain level used for the current note (used to calculate release rate if sustain changed during release stage of the current note)

value

double dsp::adsr::value

Current envelope (output) level.

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

• /home/runner/work/lmms-fork/lmms-fork/plugins/LadspaEffect/calf/veal/src/calf/envelope.h