You shouldn't need to do any uv work. Just some clever texturing. Make a gradient bar then have an alpha cutoff based on how loaded the scene is.

See Eric's answer here for a good place to start.

http://answers.unity3d.com/questions/14770/creating-a-circular-progressbar-timer.html

I'm puzzled by your 'not flexible' and 'inaccuracy' comments to @Peter G. Care to explain?

Here are two different solutions:

• Attach the following script to an empty game object.

• Drag and drop a texture onto the 'tex' variable.

• Run the app

• Adjust 'fraction' in the inspector.

  ---

  pragma strict

  var tex : Texture; var fraction : float = 0.5; private var screenRect = new Rect(0,0,200,50); private var sourceRect = new Rect(0,0,1,1);

  function Start () { screenRect.width = tex.width; screenRect.height = tex.height; }

  function OnGUI() { if(Event.current.type.Equals(EventType.Repaint)) { fraction = Mathf.Clamp01(fraction); screenRect.width = tex.width * fraction; sourceRect.width = fraction; Graphics.DrawTexture(screenRect, tex, sourceRect, 0,0,0,0); } }

For this one:

• Use the CreatePlane editor script to create a plane (1x1 vertical)

• Put a material with your texture on the plane

• Size the plane

• Attach the script below

• Specify the width in world units of the plane

• Run the app and adjust the 'fraction' in the inspector.

  ---

  pragma strict

  var fraction : float = 0.5; var width : float; // World unit width

  private var position : Vector3; private var startScaleX : float; private var scale : Vector3;

  function Start () { position = transform.position; scale = transform.localScale; startScaleX = scale.x; }

  function Update() { fraction = Mathf.Clamp01(fraction); transform.localScale.x = startScaleX * fraction;

     var posT = position;
       posT.x -= width * (1.0 - fraction) * 0.5;
       transform.position = posT;
       
       renderer.material.SetTextureScale("_MainTex", new Vector2(fraction, 1.0)); 
   }