global_settings{assumed_gamma 1.0 hf_gray_16}

camera{
  orthographic
  up y*(image_height+1)
  right x*(image_width+1)
//image size increased by 1 pixel for heightfield creation
//for just pattern use:
//  up y*image_height
//  right x*image_width
  location -z
  look_at  0
}

#declare Ptrn=
function{
  pigment{
    bozo turbulence 0.72
    color_map{
      [0 rgb 1]
      [1 rgb 0]
    }
    scale 1/2
  }
}

plane{z 0
  pigment{function{Ptrn(cos(x),sin(y),(sin(x)+cos(y))/2).gray}}
  scale <image_width,image_height,1>/radians(360)
  finish{ambient 1}
}