//  Blue sky style
//  Last edited on 1998-12-23 23:02:44 by stolfi

//  Defines
//    sib_sky_color_n  = sky color at nadir
//    sib_sky_color_h  = sky color at horizon
//    sib_sky_color_z  = sky color at zenith
//    sib_sky_pigment  = suitable for a sky_sphere

#declare sib_sky_color_n = < 0.36, 0.63, 1.00 >;
#declare sib_sky_color_h = < 0.18, 0.42, 0.90 >;
#declare sib_sky_color_z = < 0.36, 0.63, 1.00 >;

#declare sib_sky_pigment =
  pigment {
    gradient z
    color_map {
      [ 0.00  color rgb sib_sky_color_n ]
      [ 0.40  color rgb sib_sky_color_n ]
      [ 0.50  color rgb sib_sky_color_h ]
      [ 0.60  color rgb sib_sky_color_z ]
      [ 1.00  color rgb sib_sky_color_z ]
    }
    scale 2
    translate -1
  }