type t

val directional: Point.t -> Point.t -> t
val point: Point.t -> Point.t -> t
val spot: Point.t -> Point.t -> Point.t -> float -> float -> t

val color_from_lights:
  scene: Object.t ->
  pt: Point.t -> 
  v: Vector.t ->
  n: Vector.t ->
  kd: float ->
  ks: float ->
  phong: float ->
  lights: t array ->
  Point.t