Tutorial Script: DontGoTroughThings

#pragma strict

var layerMask : LayerMask; //make sure we aren't in this layer
var skinWidth : float = 0.1; //probably doesn't need to be changed
var skipFixedUpdates : int = 0;
private var skips : int;
private var minimumExtent : float;
private var partialExtent : float;
private var sqrMinimumExtent : float;
private var previousPosition : Vector3;
private var myRigidbody : Rigidbody;
//initialize values
function Awake() {
   myRigidbody = rigidbody;
   previousPosition = myRigidbody.position;
   minimumExtent = Mathf.Min(Mathf.Min(collider.bounds.extents.x, collider.bounds.extents.y), collider.bounds.extents.z);
   partialExtent = minimumExtent*(1.0 - skinWidth);
   sqrMinimumExtent = minimumExtent*minimumExtent;
}

function OnEnable() {
    myRigidbody = rigidbody;
    previousPosition = myRigidbody.position;
    minimumExtent = Mathf.Min(Mathf.Min(collider.bounds.extents.x, collider.bounds.extents.y), collider.bounds.extents.z);
    partialExtent = minimumExtent*(1.0 - skinWidth);
    sqrMinimumExtent = minimumExtent*minimumExtent;
}

function FixedUpdate() {
    if(skips >= skipFixedUpdates)
    {
        skips = 0;
        //have we moved more than our minimum extent?
        var movementThisStep : Vector3 = myRigidbody.position - previousPosition;
        var movementSqrMagnitude : float = movementThisStep.sqrMagnitude;
        if (movementSqrMagnitude > sqrMinimumExtent) {
            var movementMagnitude : float = Mathf.Sqrt(movementSqrMagnitude);
            var hitInfo : RaycastHit;
            //check for obstructions we might have missed
            if (Physics.Raycast(previousPosition, movementThisStep, hitInfo, movementMagnitude, layerMask.value))
                myRigidbody.position = hitInfo.point - (movementThisStep/movementMagnitude)*partialExtent;
        }
        previousPosition = myRigidbody.position;
    }
    else
    {
        skips += 1;
    }
}