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stk::ADSR Class Reference

STK ADSR envelope class. More...

#include <ADSR.h>

Inheritance diagram for stk::ADSR:
stk::Generator stk::Stk

Public Types

enum  {
 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.
StkFramestick (StkFrames &frames, unsigned int channel=0)
 Fill a channel of the StkFrames object with computed outputs. More...
- 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 StkFrameslastFrame (void) const
 Return an StkFrames reference to the last output sample frame.
- 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. More...

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. More...
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.
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, 1995–2014.

Member Enumeration Documentation

anonymous enum

ADSR envelope states.










Before attack / after release

29  {
31  DECAY,
34  IDLE
35  };

Member Function Documentation

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

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.

161 {
162 #if defined(_STK_DEBUG_)
163  if ( channel >= frames.channels() ) {
164  oStream_ << "ADSR::tick(): channel and StkFrames arguments are incompatible!";
165  handleError( StkError::FUNCTION_ARGUMENT );
166  }
167 #endif
169  StkFloat *samples = &frames[channel];
170  unsigned int hop = frames.channels();
171  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop )
172  *samples = ADSR::tick();
174  return frames;
175 }

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

The Synthesis ToolKit in C++ (STK)
©1995--2014 Perry R. Cook and Gary P. Scavone. All Rights Reserved.