Line render is choppy

Hi,

So what I'm trying to do is be able to click and drag the mouse to draw a line. I'm using the Line Renderer to create the line. It seems to be working, but as I drag the mouse completely vertical it looks like the rendering is incomplete and choppy. Going horizontally is fine. Below is my code and a picture of what it looks like.

 private var mouseLeftDownPoint : Vector2;
 private var mouseLeftUpPoint : Vector2;
 private var mouseDrag : boolean = false;
 private var raycastLength : float = 500;
 private var currentSelected : GameObject;
 private var movementPath : LineRenderer;
 private var numOfVertices : int = 1;
 private var vertexNo : int = 0;
 private var prevPnt : Vector3;
 private var lineTimer : float = 0;
 private var linePoints;
 
 function Start() 
 {
     movementPath = GetComponent(LineRenderer);
     prevPnt = Vector3(-1000, -1000, 0);
     linePoints = new Array(10000);
 }
 
 function Update() 
 {
     if(Input.GetButtonDown("Fire1")) 
     {
         MouseLeftDown(Input.mousePosition);
     }
 
     if (Input.GetButtonUp("Fire1")) 
     {
         MouseLeftUp(Input.mousePosition);
     }
 
     
 
     if (Input.GetButton("Fire1")) 
     {
         // Check to see if mouse is being dragged
 
         MouseLeftDrag(Input.mousePosition);
     }
 
     
 
     if(!mouseDrag)
     {
         lineTimer += Time.deltaTime;
         if(lineTimer > 1)
         {
             lineTimer = 0;
         }
     }
 }
 
 function MouseLeftDown(screenPosition : Vector2) 
 {
     mouseLeftDownPoint = screenPosition;    
 
     var hit : RaycastHit;
     var ray = Camera.main.ScreenPointToRay(mouseLeftUpPoint);
 
     if(Physics.Raycast(ray, hit, raycastLength)) 
     {
         Debug.Log(hit.point);
         numOfVertices = 1;
         vertexNo = 0;
         movementPath.SetVertexCount(numOfVertices);
         movementPath.SetPosition(0, hit.point);
     }
 }
 
 function MouseLeftUp(screenPosition : Vector2) 
 {
     mouseLeftUpPoint = screenPosition;
     mouseDrag = false;
 
     var hit : RaycastHit;
     var ray = Camera.main.ScreenPointToRay(mouseLeftUpPoint);
 
     if(Physics.Raycast(ray, hit, raycastLength)) 
     {
         Debug.Log(hit.point);
         // We hit a unit, now select it
         if(hit.collider.gameObject.name == "Spaceship")
         {
             currentSelected = hit.collider.gameObject;
             currentSelected.SendMessage("Selected");            
         }
     }
 }
 
 function MouseLeftDrag(screenPosition : Vector2)
 {
     if(screenPosition != mouseLeftDownPoint)
     {
         mouseDrag = true;
 
         var hit : RaycastHit;
         var ray = Camera.main.ScreenPointToRay(screenPosition);
 
         if(Physics.Raycast(ray, hit, raycastLength))
         {
             Debug.Log("hit point is " + hit.point);
             if(hit.point == prevPnt)
             {
                 // Don't do anything if the mouse is staying put
             }
             else
             {
                 movementPath.SetVertexCount(numOfVertices);
                 movementPath.SetPosition(vertexNo, hit.point);
                 numOfVertices++;
                 vertexNo++;
                 prevPnt = hit.point;
             }
         }
     }
 }
 
 @script RequireComponent(LineRenderer)

I'm not sure if it's the way I'm drawing it, or is it because the way Line Renderer works that it doesn't work well when rendering lines in real-time?

Any input is welcome :D.