stk/ADSR.cpp

/*******************************************/
/*  ADSR Subclass of the Envelope Class,   */
/*  by Perry R. Cook, 1995-96              */ 
/*  This is the traditional ADSR (Attack   */
/*  Decay, Sustain, Release) ADSR.         */
/*  It responds to simple KeyOn and KeyOff */
/*  messages, keeping track of it's state. */         
/*  There are two tick (update value)      */
/*  methods, one returns the value, and    */
/*  other returns the state (0 = A, 1 = D, */
/*  2 = S, 3 = R)                          */
/*******************************************/

#include "ADSR.h"    

ADSR :: ADSR() : Envelope()
{    
  target = (MY_FLOAT) 0.0;
  value = (MY_FLOAT) 0.0;
  attackRate = (MY_FLOAT) 0.001;
  decayRate = (MY_FLOAT) 0.001;
  sustainLevel = (MY_FLOAT) 0.5;
  releaseRate = (MY_FLOAT) 0.01;
  state = 0;
}

ADSR :: ~ADSR()
{    
  /* Nothing to do here */
}

void ADSR :: keyOn()
{
  target = (MY_FLOAT) 1.0;
  rate = attackRate;
  state = 0;
}

void ADSR :: keyOff()
{
  target = (MY_FLOAT) 0.0;
  rate = releaseRate;
  state = 3;
}

void ADSR :: setAttackRate(MY_FLOAT aRate)
{
  if (aRate < 0.0) {
    printf("negative rates not allowed!!, correcting\n");
    attackRate = -aRate;
  }
  else attackRate = aRate;
}

void ADSR :: setDecayRate(MY_FLOAT aRate)
{
  if (aRate < 0.0) {
    printf("negative rates not allowed!!, correcting\n");
    decayRate = -aRate;
  }
  else decayRate = aRate;
}

void ADSR :: setSustainLevel(MY_FLOAT aLevel)
{
  if (aLevel < 0.0 ) {
    printf("Sustain level out of range!!, correcting\n");
    sustainLevel = (MY_FLOAT)  0.0;
  }
  else sustainLevel = aLevel;
}

void ADSR :: setReleaseRate(MY_FLOAT aRate)
{
  if (aRate < 0.0) {
    printf("negative rates not allowed!!, correcting\n");
    releaseRate = -aRate;
  }
  else releaseRate = aRate;
}

void ADSR :: setAttackTime(MY_FLOAT aTime)
{
  if (aTime < 0.0) {
    printf("negative times not allowed!!, correcting\n");
    attackRate = ONE_OVER_SRATE / -aTime;
  }
  else attackRate = ONE_OVER_SRATE / aTime;
}

void ADSR :: setDecayTime(MY_FLOAT aTime)
{
  if (aTime < 0.0) {
    printf("negative times not allowed!!, correcting\n");
    decayRate = ONE_OVER_SRATE / -aTime;
  }
  else decayRate = ONE_OVER_SRATE / aTime;
}

void ADSR :: setReleaseTime(MY_FLOAT aTime)
{
  if (aTime < 0.0) {
    printf("negative times not allowed!!, correcting\n");
    releaseRate = ONE_OVER_SRATE / -aTime;
  }
  else releaseRate = ONE_OVER_SRATE / aTime;
}

void ADSR :: setAllTimes(MY_FLOAT attTime, MY_FLOAT decTime, MY_FLOAT susLevel, MY_FLOAT relTime)
{
  this->setAttackTime(attTime);
  this->setDecayTime(decTime);
  this->setSustainLevel(susLevel);
  this->setReleaseTime(relTime);
}

void ADSR :: setTarget(MY_FLOAT aTarget)
{
  target = aTarget;
  if (value < target) {
    state = ATTACK;
    this->setSustainLevel(target);
    rate = attackRate;
  }
  if (value > target) {
    this->setSustainLevel(target);
    state = DECAY;
    rate = decayRate;
  }
}

void ADSR :: setValue(MY_FLOAT aValue)
{
  state = SUSTAIN;
  target = aValue;
  value = aValue;
  this->setSustainLevel(aValue);
  rate = (MY_FLOAT)  0.0;
}

MY_FLOAT ADSR :: tick()
{
  if (state==ATTACK)  {
    value += rate;
    if (value >= target)    {
      value = target;
      rate = decayRate;
      target = sustainLevel;
	    state = DECAY;
    }
  }    
  else if (state==DECAY)  {
    value -= decayRate;
    if (value <= sustainLevel)    {
      value = sustainLevel;
      rate = (MY_FLOAT) 0.0;
      state = SUSTAIN;
    }
  }
  else if (state==RELEASE)  {
    value -= releaseRate;
    if (value <= 0.0)       {
      value = (MY_FLOAT) 0.0;
      state = 4;
    }
  }
  return value;
}

int ADSR :: informTick()
{
  this->tick();
  return state;
}

MY_FLOAT ADSR :: lastOut()
{
  return value;
}

/************  Test Main  ************************/
/*
void main()
{
    long i;
    ADSR test;
    
    test.setAttackRate(0.15);
    test.keyOn();
    while(test.informTick()==ATTACK) printf("%lf\n",test.tick());
    test.setDecayRate(0.1);
    while (test.informTick()==DECAY) printf("%lf\n",test.lastOut());
    test.setReleaseRate(0.05);
    test.keyOff();
    while(test.informTick()==RELEASE) printf("%lf\n",test.lastOut());
}
*/