Game Physics Engine Development, 2nd Edition

6.2 Spring-Like Force Generators 97

/**

* Holds the length of the bungee at the point it begins to

* generate a force.

*/

real restLength;

public:

/** Creates a new bungee with the given parameters. */

ParticleBungee(Particle *other,

real springConstant, real restLength);

/** Applies the spring force to the given particle. */

virtual void updateForce(Particle *particle, real duration);

};

Excerpt from file src/pfgen.cpp

void ParticleBungee::updateForce(Particle* particle, real duration)

{

// Calculate the vector of the spring.

Vector3 force;

particle->getPosition(&force);

force -= other->getPosition();

// Check if the bungee is compressed.

real magnitude = force.magnitud ...