                 collisions.push(c) if c
         return collisions
 
-    # Return a collision if the two elements are colliding, null 
+    # Return a collision if the two elements are colliding, null
     # otherwise.
     detectCollision : (e1, e2) ->
         #FIXME: add an error of margin

    # Resolve the collision so as to prevent further handler.
    resolve : () ->
        @resolved = true
    
    # Return true if the collision has been resolved.
    isResolved : () ->
        return @resolved


    # Return the collision's contact normal vector, relative
    # to the first element in the collision.
    getContactNormal : () ->
        return @getRelativeVelocity().normalize()

    # Return the seperating velocity of the two elements.
    getSeperatingVelocity : () ->
        return @getRelativeVelocity().dotProduct(@getContactNormal())
