(* $Id: glMisc.ml,v 1.8 2008-10-25 02:22:58 garrigue Exp $ *) open StdLabels external get_string : [`vendor|`renderer|`version|`extensions] -> string    = "ml_glGetString" let rec check_substring ~sep ~start ~buf s =  let len = String.length s in  if String.length buf < len + start then false else  if String.sub buf ~pos:start ~len = s &&    (String.length buf = len + start || buf.[len+start] = sep) then true  else match    try Some (String.index_from buf start sep) with Not_found -> None  with  | None -> false  | Some n -> check_substring ~sep ~start:(n+1) ~buf s let check_extension s =  check_substring ~sep:' ' ~start:0 ~buf:(get_string `extensions) s type equation = float * float * float * floatexternal clip_plane : plane:int -> equation -> unit    = "ml_glClipPlane"let clip_plane ~plane equation =  if plane < 0 || plane > 5 then invalid_arg "Gl.clip_plane";  clip_plane ~plane equation type hint_target =    [`fog|`line_smooth|`perspective_correction|`point_smooth|`polygon_smooth]external hint : hint_target -> [`fastest|`nicest|`dont_care] -> unit    = "ml_glHint" external init_names : unit -> unit = "ml_glInitNames"external load_name : int -> unit = "ml_glLoadName"external pop_name : unit -> unit = "ml_glPopName"external push_name : int -> unit = "ml_glPushName" external pop_attrib : unit -> unit = "ml_glPopAttrib"type attrib =    [ `accum_buffer|`color_buffer|`current|`depth_buffer|`enable|`eval|`fog    | `hint|`lighting|`line|`list|`pixel_mode|`point|`polygon|`polygon_stipple    | `scissor|`stencil_buffer|`texture|`transform|`viewport ]external push_attrib : attrib list -> unit = "ml_glPushAttrib" external pass_through : float -> unit = "ml_glPassThrough"external render_mode : [`render|`select|`feedback] -> int = "ml_glRenderMode"external select_buffer : int -> [`uint] Raw.t -> unit = "ml_glSelectBuffer"let select_buffer raw =  if not (Raw.static raw) then    invalid_arg "GlMisc.select_buffer : buffer must be static";  select_buffer (Raw.length raw) rawtype feedback_mode =    [`_2d |`_3d |`_3d_color |`_3d_color_texture |`_4d_color_texture]external feedback_buffer : int -> feedback_mode -> [`float] Raw.t -> unit  = "ml_glFeedbackBuffer"let feedback_buffer ~mode buf =  if not (Raw.static buf) then    invalid_arg "GlMisc.feedback_buffer : buffer must be static";  feedback_buffer (Raw.length buf) mode buf external scissor : x:int -> y:int -> width:int -> height:int -> unit  = "ml_glScissor"