public void applyForce() {
// force is proportional to the diff between restLen and current idst
// a vector from A --> B
Vector diff = new Vector(endA.pos, endB.pos);
// compute the current distance
float dist = diff.getMagnitude();
// compute dx, which is what the force depends on
float dx = Math.abs(dist - restLen);
// a vector containing just the direction component of A --> B
Vector dir = diff.copy().normalize();
Vector force = dir.copy().scale(-K * dx, -K * dx);
if (restLen < getDistance()) {
// forces go INWARDS
endB.addForce(force);
endA.addForce(force.reverse());
} else {
// forces go OUTWARDS
endA.addForce(force);
endB.addForce(force.reverse());
}
}
public float getKineticEnergy() {
float speed = vel.getMagnitude();
float ke = 0.5f * mass * speed * speed;
return ke; // 0.5 m * (v^2)
}