@script ExecuteInEditMode
  
  class EdgeDetectEffectNormals extends ImageEffectBase
  {        
          function Start() {
                  camera.depthTextureMode = DepthTextureMode.DepthNormals;
          }
                  
          function OnRenderImage (source : RenderTexture, destination : RenderTexture)
          {
                  ImageEffects.BlitWithMaterial (material, source, destination);
          }
  }