stk::ADSR Class Reference

STK ADSR envelope class. More...

#include <ADSR.h>

Inheritance diagram for stk::ADSR:

Public Types
enum	{   ATTACK , DECAY , SUSTAIN , RELEASE ,   IDLE }
	ADSR envelope states. More...

Public Member Functions
	ADSR (void)
	Default constructor.
	~ADSR (void)
	Class destructor.
void	keyOn (void)
	Set target = 1, state = ADSR::ATTACK.
void	keyOff (void)
	Set target = 0, state = ADSR::RELEASE.
void	setAttackRate (StkFloat rate)
	Set the attack rate (gain / sample).
void	setAttackTarget (StkFloat target)
	Set the target value for the attack (default = 1.0).
void	setDecayRate (StkFloat rate)
	Set the decay rate (gain / sample).
void	setSustainLevel (StkFloat level)
	Set the sustain level.
void	setReleaseRate (StkFloat rate)
	Set the release rate (gain / sample).
void	setAttackTime (StkFloat time)
	Set the attack rate based on a time duration (seconds).
void	setDecayTime (StkFloat time)
	Set the decay rate based on a time duration (seconds).
void	setReleaseTime (StkFloat time)
	Set the release rate based on a time duration (seconds).
void	setAllTimes (StkFloat aTime, StkFloat dTime, StkFloat sLevel, StkFloat rTime)
	Set sustain level and attack, decay, and release time durations (seconds).
void	setTarget (StkFloat target)
	Set a sustain target value and attack or decay from current value to target.
int	getState (void) const
	Return the current envelope state (ATTACK, DECAY, SUSTAIN, RELEASE, IDLE).
void	setValue (StkFloat value)
	Set to state = ADSR::SUSTAIN with current and target values of value.
StkFloat	lastOut (void) const
	Return the last computed output value.
StkFloat	tick (void)
	Compute and return one output sample.
StkFrames &	tick (StkFrames &frames, unsigned int channel=0)
	Fill a channel of the StkFrames object with computed outputs.
Public Member Functions inherited from stk::Generator
	Generator (void)
	Class constructor.
unsigned int	channelsOut (void) const
	Return the number of output channels for the class.
const StkFrames &	lastFrame (void) const
	Return an StkFrames reference to the last output sample frame.
virtual StkFrames &	tick (StkFrames &frames, unsigned int channel=0)=0
	Fill the StkFrames object with computed sample frames, starting at the specified channel.
Public Member Functions inherited from stk::Stk
void	ignoreSampleRateChange (bool ignore=true)
	A function to enable/disable the automatic updating of class data when the STK sample rate changes.

Additional Inherited Members
Static Public Member Functions inherited from stk::Stk
static StkFloat	sampleRate (void)
	Static method that returns the current STK sample rate.
static void	setSampleRate (StkFloat rate)
	Static method that sets the STK sample rate.
static void	clear_alertList ()
	Static method that frees memory from alertList_.
static std::string	rawwavePath (void)
	Static method that returns the current rawwave path.
static void	setRawwavePath (std::string path)
	Static method that sets the STK rawwave path.
static void	swap16 (unsigned char *ptr)
	Static method that byte-swaps a 16-bit data type.
static void	swap32 (unsigned char *ptr)
	Static method that byte-swaps a 32-bit data type.
static void	swap64 (unsigned char *ptr)
	Static method that byte-swaps a 64-bit data type.
static void	sleep (unsigned long milliseconds)
	Static cross-platform method to sleep for a number of milliseconds.
static bool	inRange (StkFloat value, StkFloat min, StkFloat max)
	Static method to check whether a value is within a specified range.
static void	handleError (const char *message, StkError::Type type)
	Static function for error reporting and handling using c-strings.
static void	handleError (std::string message, StkError::Type type)
	Static function for error reporting and handling using c++ strings.
static void	showWarnings (bool status)
	Toggle display of WARNING and STATUS messages.
static void	printErrors (bool status)
	Toggle display of error messages before throwing exceptions.
Static Public Attributes inherited from stk::Stk
static const StkFormat	STK_SINT8
static const StkFormat	STK_SINT16
static const StkFormat	STK_SINT24
static const StkFormat	STK_SINT32
static const StkFormat	STK_FLOAT32
static const StkFormat	STK_FLOAT64
Protected Member Functions inherited from stk::Stk
	Stk (void)
	Default constructor.
virtual	~Stk (void)
	Class destructor.
virtual void	sampleRateChanged (StkFloat newRate, StkFloat oldRate)
	This function should be implemented in subclasses that depend on the sample rate.
void	addSampleRateAlert (Stk *ptr)
	Add class pointer to list for sample rate change notification.
void	removeSampleRateAlert (Stk *ptr)
	Remove class pointer from list for sample rate change notification.
void	handleError (StkError::Type type) const
	Internal function for error reporting that assumes message in oStream_ variable.

Detailed Description

STK ADSR envelope class.

This class implements a traditional ADSR (Attack, Decay, Sustain, Release) envelope. It responds to simple keyOn and keyOff messages, keeping track of its state. The state = ADSR::IDLE before being triggered and after the envelope value reaches 0.0 in the ADSR::RELEASE state. All rate, target and level settings must be non-negative. All time settings are in seconds and must be positive.

by Perry R. Cook and Gary P. Scavone, 1995–2023.

Member Enumeration Documentation

anonymous enum

anonymous enum

ADSR envelope states.

Enumerator
ATTACK	Attack
DECAY	Decay
SUSTAIN	Sustain
RELEASE	Release
IDLE	Before attack / after release

       {
    ATTACK,   
    DECAY,    
    SUSTAIN,  
    RELEASE,  
    IDLE      
  };

Member Function Documentation

tick()

StkFrames & stk::ADSR::tick ( StkFrames &  frames, unsigned int  channel = 0  )

inlinevirtual

Fill a channel of the StkFrames object with computed outputs.

The channel argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

Implements stk::Generator.

{
#if defined(_STK_DEBUG_)
  if ( channel >= frames.channels() ) {
    oStream_ << "ADSR::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *samples = &frames[channel];
  unsigned int hop = frames.channels();
  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop )
    *samples = ADSR::tick();
 
  return frames;
}

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

• ADSR.h