type winding_rule =
    [ `abs_geq_two | `negative | `nonzero | `odd | `positive ]
type vertices = (float * float * float) list
val tesselate :
  ?winding:winding_rule ->
  ?boundary_only:bool -> ?tolerance:float -> vertices list -> unit
type triangles =
  GluTess.triangles = {
  singles : vertices list;
  strips : vertices list;
  fans : vertices list;
}
val tesselate_and_return :
  ?winding:winding_rule -> ?tolerance:float -> vertices list -> triangles