SimpleVelocityLimiter.js

#pragma strict

// original maxvelocity on player gameobject as of 4/4/2012: 120
// This MonoBehaviour uses hard clamping to limit the velocity of a rigidbody.

// The maximum allowed velocity. The velocity will be clamped to keep
// it from exceeding this value.
var maxVelocity : float;

// The cached rigidbody reference.
private var rb : Rigidbody;
// A cached copy of the squared max velocity. Used in FixedUpdate.
private var sqrMaxVelocity : float;

// Awake is a built-in unity function that is called called only once during the lifetime of the script instance.
// It is called after all objects are initialized.
// For more info, see:
// http://unity3d.com/support/documentation/ScriptReference/MonoBehaviour.Awake.html
function Awake() {
	rb = GetComponent.<Rigidbody>();
	SetMaxVelocity(maxVelocity);
}

// Sets the max velocity and calculates the squared max velocity for use in FixedUpdate.
// Outside callers who wish to modify the max velocity should use this function. Otherwise,
// the cached squared velocity will not be recalculated.
function SetMaxVelocity(maxVelocity : float){
	this.maxVelocity = maxVelocity;
	sqrMaxVelocity = maxVelocity * maxVelocity;
}

function GetMaxVelocity() {
	return maxVelocity;
}

// FixedUpdate is a built-in Unity function that is called every fixed framerate frame.
// We use FixedUpdate instead of Update here because the docs recommend doing so when
// dealing with rigidbodies.
// For more info, see:
// http://unity3d.com/support/documentation/ScriptReference/MonoBehaviour.FixedUpdate.html
function FixedUpdate() {
	var v = rb.velocity;
	// Clamp the velocity, if necessary
	// Use sqrMagnitude instead of magnitude for performance reasons.
	if ((v.sqrMagnitude > sqrMaxVelocity) && (rb.isKinematic == false)) { // Equivalent to: rigidbody.velocity.magnitude > maxVelocity, but faster.
		// Vector3.normalized returns this vector with a magnitude
		// of 1. This ensures that we're not messing with the
		// direction of the vector, only its magnitude.
		rb.velocity = v.normalized * maxVelocity;
	}
//			Debug.Log (rb.velocity);
}

// Require a Rigidbody component to be attached to the same GameObject.
@script RequireComponent(Rigidbody)