robert@464: /*
robert@464:  *
robert@464:  * Excitation Junction for two waveguides
robert@464:  *
robert@464:  * Christian Heinrichs 04/2015
robert@464:  *
robert@464:  */
robert@464: 
robert@464: #include "Junction.h"
robert@464: #include "../include/Utilities.h"
robert@464: 
robert@464: Junction::Junction()	{
robert@464: 
robert@464: 	setFrequency(440);
robert@464: 	_dt = 1.0/44100.0;
robert@464: 
robert@464: 	// initialize variables
robert@464: 	for(int i=0;i<WG_BUFFER_SIZE;i++)	{
robert@464: 		_buffer_l[i] = 0;
robert@464: 		_buffer_r[i] = 0;
robert@464: 	}
robert@464: 	_excitation = 0;
robert@464: 	_lastPlectrumDisplacement = 0;
robert@464: 	_readPtr = 0;
robert@464: 
robert@464: }
robert@464: 
robert@464: void Junction::update(float excitation, float left, float right)	{
robert@464: 
robert@464: 	// 1. advance delay buffer read pointer
robert@464: 
robert@464: 	if(++_readPtr>=WG_BUFFER_SIZE)
robert@464: 		_readPtr=0;
robert@464: 
robert@464: 	// 2. add excitation sample into buffer
robert@464: 
robert@464: 	_buffer_l[(_readPtr+_delay_l+WG_BUFFER_SIZE)%WG_BUFFER_SIZE] = excitation;
robert@464: 	_buffer_r[(_readPtr+_delay_r+WG_BUFFER_SIZE)%WG_BUFFER_SIZE] = excitation;
robert@464: 
robert@464: 	// 3. feed right input to left output and vice versa
robert@464: 
robert@464: 	_buffer_l[_readPtr] += right;
robert@464: 	_buffer_r[_readPtr] += left;
robert@464: 
robert@464: 	// 4. store excitation value for later use
robert@464: 	_excitation = excitation;
robert@464: 
robert@464: }
robert@464: 
robert@464: float Junction::getOutput(int direction)	{
robert@464: 
robert@464: 	if(direction = 0)
robert@464: 		return _buffer_l[_readPtr];
robert@464: 	else
robert@464: 		return _buffer_r[_readPtr];
robert@464: 
robert@464: }
robert@464: 
robert@464: float Junction::getExcitationDisplacement()	{
robert@464: 
robert@464: 	// string displacement and excitation force
robert@464: 	// use delayed value to account for excitation position
robert@464: 	float in = _buffer_l[(_readPtr+_delay_l+WG_BUFFER_SIZE)%WG_BUFFER_SIZE] + _excitation;
robert@464: 
robert@464: 	// integrate total force
robert@464: 	float out = 0.00001 * in + 0.99999 * _lastPlectrumDisplacement;
robert@464: 
robert@464: 	// store variable for next iteration
robert@464: 	_lastPlectrumDisplacement = out;
robert@464: 
robert@464: 	// multiply by delta time
robert@464: 	return out * _dt;
robert@464: 
robert@464: }
robert@464: 
robert@464: void Junction::setPluckPosition(float pluckPos){
robert@464: 
robert@464: 	pluckPos = constrain(pluckPos,0,1);
robert@464: 	_delay_l = pluckPos * _periodInSamples;
robert@464: 	_delay_r = (1-pluckPos) * _periodInSamples;
robert@464: 
robert@464: }
robert@464: 
robert@464: void Junction::setPeriod(float period)	{
robert@464: 
robert@464: 	_periodInMilliseconds = period;
robert@464: 
robert@464: }
robert@464: 
robert@464: void Junction::setFrequency(float frequency)	{
robert@464: 
robert@464: 	_periodInMilliseconds = 1000.0/frequency;
robert@464: 	_periodInSamples = (int)(_periodInMilliseconds * 44.1);
robert@464: 
robert@464: }