// attract positive repel negative



#pragma once



#include "Force.h"

#include "Particle.h"



namespace traer { namespace physics {



class Attraction : public Force

{

public:



	Particle* a;

	Particle* b;

	float k;

	bool on;

	float distanceMin;

	float distanceMinSquared;

	

	Attraction( Particle* a, Particle* b, float k, float distanceMin );



	float getMinimumDistance();



	void setMinimumDistance( float d );



	void turnOff();



	void turnOn();



	void setStrength( float k );



	Particle* getOneEnd();



	Particle* getTheOtherEnd();



	void apply();



	float getStrength();



	bool isOn() const;

	

	bool isOff() const;

	

private:

    // http://en.wikipedia.org/wiki/Fast_inverse_square_root

    float Q_rsqrt( float number );

    

};



} } // namespace traer::physics