stk/STK/Bowed.cpp

/******************************************/
/*  Bowed String model ala Smith          */
/*  after McIntyre, Schumacher, Woodhouse */
/*  by Perry Cook, 1995-96                */
/*                                        */
/*  This is a waveguide model, and thus   */
/*  relates to various Stanford Univ.     */
/*  and possibly Yamaha and other patents.*/
/*                                        */
/*   Controls:    CONTROL1 = bowPressure  */
/*                CONTROL2 = bowPosition  */
/*	                CONTROL3 = vibrFreq     */
/*                MOD_WHEEL= vibrGain     */
/*                                        */
/******************************************/

#include "Bowed.h"
#include "SKINI11.msg"

Bowed :: Bowed(MY_FLOAT lowestFreq)
{
  long length;
  length = (long) (SRATE / lowestFreq + 1);
  neckDelay = new DLineL(length);
  length >>= 1;
  bridgeDelay = new DLineL(length);
  bowTabl = new BowTabl;
  reflFilt = new OnePole;
  bodyFilt = new BiQuad;

  // Concatenate the STK RAWWAVE_PATH to the rawwave file
  char file[128];
  strcpy(file, RAWWAVE_PATH);
  vibr = new RawWvIn(strcat(file,"rawwaves/sinewave.raw"),"looping");

  adsr = new ADSR;
  vibrGain = (MY_FLOAT) 0.0;

  neckDelay->setDelay((MY_FLOAT) 100.0);
  bridgeDelay->setDelay((MY_FLOAT) 29.0);

  bowTabl->setSlope((MY_FLOAT) 3.0);

  reflFilt->setPole((MY_FLOAT) (0.6 - (0.1 * 22050.0 / SRATE)));
  reflFilt->setGain((MY_FLOAT) 0.95);

  bodyFilt->setFreqAndReson((MY_FLOAT) 500.0, (MY_FLOAT) 0.85);
  bodyFilt->setEqualGainZeroes();
  bodyFilt->setGain((MY_FLOAT) 0.2);

  vibr->normalize();
  vibr->setFreq((MY_FLOAT) 6.12723);

  adsr->setAllTimes((MY_FLOAT) 0.02,(MY_FLOAT) 0.005,(MY_FLOAT) 0.9,(MY_FLOAT) 0.01);
    
  betaRatio = (MY_FLOAT) 0.127236;
}

Bowed :: ~Bowed()
{
  delete neckDelay;
  delete bridgeDelay;
  delete bowTabl;
  delete reflFilt;
  delete bodyFilt;
  delete vibr;
  delete adsr;
}

void Bowed :: clear()
{
  neckDelay->clear();
  bridgeDelay->clear();
}

void Bowed :: setFreq(MY_FLOAT frequency)
{
  baseDelay = SRATE / frequency - (MY_FLOAT) 4.0;   	/* delay - approx. filter delay */
  bridgeDelay->setDelay(baseDelay * betaRatio); 	    /* bow to bridge length */
  neckDelay->setDelay(baseDelay * ((MY_FLOAT) 1.0 - betaRatio)); /* bow to nut (finger) length */
}

void Bowed :: startBowing(MY_FLOAT amplitude, MY_FLOAT rate)
{
  adsr->setRate(rate);
  adsr->keyOn();
  maxVelocity = (MY_FLOAT) 0.03 + ((MY_FLOAT) 0.2 * amplitude); 
}

void Bowed :: stopBowing(MY_FLOAT rate)
{
  adsr->setRate(rate);
  adsr->keyOff();
}

void Bowed :: noteOn(MY_FLOAT freq, MY_FLOAT amp)
{
  this->startBowing(amp,amp * (MY_FLOAT) 0.001);
  this->setFreq(freq);
#if defined(_debug_)        
  printf("Bowed : NoteOn: Freq=%lf Amp=%lf\n",freq,amp);
#endif    
}

void Bowed :: noteOff(MY_FLOAT amp)
{
  this->stopBowing(((MY_FLOAT) 1.0 - amp) * (MY_FLOAT) 0.005);
#if defined(_debug_)        
  printf("Bowed : NoteOff: Amp=%lf\n",amp);
#endif    
}

void Bowed :: setVibrato(MY_FLOAT amount)
{
  vibrGain = amount;
}

MY_FLOAT Bowed :: tick()
{
  MY_FLOAT bowVelocity;
  MY_FLOAT bridgeRefl=(MY_FLOAT) 0,nutRefl=(MY_FLOAT) 0;
  MY_FLOAT newVel=(MY_FLOAT) 0,velDiff=(MY_FLOAT) 0,stringVel=(MY_FLOAT) 0;
    
  bowVelocity = maxVelocity * adsr->tick();

  bridgeRefl = -reflFilt->tick(
                               bridgeDelay->lastOut());          /* Bridge Reflection      */
  nutRefl = -neckDelay->lastOut();              /* Nut Reflection         */
  stringVel = bridgeRefl + nutRefl;             /* Sum is String Velocity */
  velDiff = bowVelocity - stringVel;            /* Differential Velocity  */
  newVel = velDiff * bowTabl->lookup(velDiff);  /* Non-Lin Bow Function   */
  neckDelay->tick(bridgeRefl + newVel);         /* Do string              */     
  bridgeDelay->tick(nutRefl + newVel);          /*   propagations         */
    
  if (vibrGain > 0.0)  {
    neckDelay->setDelay((baseDelay * ((MY_FLOAT) 1.0 - betaRatio)) + 
                        (baseDelay * vibrGain*vibr->tick()));
  }

  lastOutput = bodyFilt->tick(bridgeDelay->lastOut());                 

  return lastOutput;
}

void Bowed :: controlChange(int number, MY_FLOAT value)
{
#if defined(_debug_)        
  printf("Bowed : ControlChange: Number=%i Value=%f\n",number,value);
#endif    
  if (number == __SK_BowPressure_)
		bowTabl->setSlope((MY_FLOAT) 5.0 - ((MY_FLOAT) 4.0 * value * NORM_7));
  else if (number == __SK_BowPosition_)	{
		betaRatio = (MY_FLOAT) 0.027236 + ((MY_FLOAT) 0.2 * value * NORM_7);
    bridgeDelay->setDelay(baseDelay * betaRatio); 	/* bow to bridge length   */
    neckDelay->setDelay(baseDelay * ((MY_FLOAT) 1.0 - betaRatio)); /* bow to nut (finger) length   */
  }
  else if (number == __SK_ModFrequency_)
    vibr->setFreq((value * NORM_7 * (MY_FLOAT) 12.0));
  else if (number == __SK_ModWheel_)
    vibrGain = (value * NORM_7 * (MY_FLOAT) 0.4);
  else if (number == __SK_AfterTouch_Cont_)
    adsr->setTarget(value * NORM_7);
  else    {        
    printf("Bowed : Undefined Control Number!!\n");
  }    
}