void evaluatePixel()
    {    
      float2 pos = (outCoord() - center) / imgSize;
  
      float pi = 3.141592653589793;
      float a = atan(pos.y,pos.x);
      float r = sqrt(pow(pos.x,2.0)+pow(pos.y,2.0));
      
      float u = 0.0;
      float v = 0.0;
      float w = 0.0;