robert@464: /*
robert@464:  *
robert@464:  * Plectrum model for touching and plucking strings
robert@464:  *
robert@464:  * Christian Heinrichs 04/2015
robert@464:  *
robert@464:  * [inspired by E. Berdahl's pluck~ abstraction for the FireFader]
robert@464:  *
robert@464:  */
robert@464: 
robert@464: #include "Plectrum.h"
robert@464: 
robert@464: #include "../include/Utilities.h"
robert@464: #include <cmath>
robert@464: #include <stdio.h>
robert@464: #include <cstdlib>
robert@464: 
robert@464: Plectrum::Plectrum()	{
robert@464: 
robert@464: 	_contact = 0;
robert@464: 	_lastDistance = 0;
robert@464: 
robert@464: }
robert@464: 
robert@464: void Plectrum::setup(float spring, float damp, float hyst)	{
robert@464: 
robert@464: 	_spring = spring;
robert@464: 	_damp = damp;
robert@464: 	_hyst = hyst;
robert@464: 
robert@464: }
robert@464: 
robert@464: float Plectrum::update(float position, float stringPosition)	{
robert@464: 
robert@464: 	float distance = position - stringPosition;
robert@464: 
robert@464: 	// Calculate spring/damp forces based on distance to string
robert@464: 
robert@464: 	float springOut = distance * _spring;
robert@464: 
robert@464: 	float dampOut = (distance - _lastDistance) * 44100;
robert@464: 
robert@464: 	float out = springOut+dampOut;
robert@464: 
robert@464: 	// If distance crosses zero, enable contact
robert@464: 
robert@464: 	if((distance>0 && _lastDistance<=0)||(distance<0 && _lastDistance>=0))
robert@464: 		_contact = 1;
robert@464: 
robert@464: 	// If distance exceeds hysteresis threshold, jump to zero (i.e. 'pluck')
robert@464: 
robert@464: 	if(fabs(distance)>_hyst)
robert@464: 		_contact = 0;
robert@464: 
robert@464: 	// FIXME: contact doesn't switch back to zero if distance goes back in original direction
robert@464: 
robert@464: 	_lastDistance = distance;
robert@464: 
robert@464: 	return out * _contact;
robert@464: 
robert@464: }