type color_material =
    [ `ambient | `ambient_and_diffuse | `diffuse | `emission | `specular ]
val color_material : face:Gl.face -> color_material -> unit
type fog_param =
    [ `End of float
    | `color of Gl.rgba
    | `density of float
    | `index of float
    | `mode of [ `exp | `exp2 | `linear ]
    | `start of float ]
val fog : fog_param -> unit
type light_param =
    [ `ambient of Gl.rgba
    | `constant_attenuation of float
    | `diffuse of Gl.rgba
    | `linear_attenuation of float
    | `position of Gl.point4
    | `quadratic_attenuation of float
    | `specular of Gl.rgba
    | `spot_cutoff of float
    | `spot_direction of Gl.point3
    | `spot_exponent of float ]
val light : num:int -> light_param -> unit
val light_model :
  [ `ambient of Gl.rgba
  | `color_control of [ `separate_specular_color | `single_color ]
  | `local_viewer of bool
  | `two_side of bool ] -> unit
type material_param =
    [ `ambient of Gl.rgba
    | `ambient_and_diffuse of Gl.rgba
    | `color_indexes of float * float * float
    | `diffuse of Gl.rgba
    | `emission of Gl.rgba
    | `shininess of float
    | `specular of Gl.rgba ]
val material : face:Gl.face -> material_param -> unit