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(*    Lablgtk - Examples                                                  *)
(*                                                                        *)
(*    This code is in the public domain.                                  *)
(*    You may freely copy parts of it in your application.                *)
(*                                                                        *)
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(* $Id$ *)

(*
 * 3-D gear wheels.  This program is in the public domain.
 *
 * Brian Paul
 * LablGL version by Jacques Garrigue
 * Lablgtk version by Eric Cooper <ecc@cmu.edu>
 *)

open StdLabels

let pi = acos (-1.)

(*
 * Draw a gear wheel.  You'll probably want to call this function when
 * building a display list since we do a lot of trig here.
 *
 * Input:  inner_radius - radius of hole at center
 *         outer_radius - radius at center of teeth
 *         width - width of gear
 *         teeth - number of teeth
 *         tooth_depth - depth of tooth
 *)
let gear ~inner ~outer ~width ~teeth ~tooth_depth =
  let r0 = inner
  and r1 = outer -. tooth_depth /. 2.0
  and r2 = outer +. tooth_depth /. 2.0 in

  let ta = 2.0 *. pi /. float teeth in
  let da = ta /. 4.0 in

  GlDraw.shade_model `flat;

  GlDraw.normal ~z:1.0 ();

  let vertex ~r ~z ?(s=0) i =
    let angle = float i *. ta +. float s *. da in
    GlDraw.vertex ~x:(r *. cos angle) ~y:(r *. sin angle) ~z ()
  in

  (* draw front face *)
  let z = width *. 0.5 in
  GlDraw.begins `quad_strip;
  for i=0 to teeth do
    vertex i ~r:r0 ~z;
    vertex i ~r:r1 ~z;
    vertex i ~r:r0 ~z;
    vertex i ~r:r1 ~z ~s:3;
  done;
  GlDraw.ends ();
  
  (* draw front sides of teeth *)
  GlDraw.begins `quads;
  for i=0 to teeth - 1 do
    vertex i ~r:r1 ~z;
    vertex i ~r:r2 ~s:1 ~z;
    vertex i ~r:r2 ~s:2 ~z;
    vertex i ~r:r1 ~s:3 ~z;
  done;
  GlDraw.ends ();

  GlDraw.normal ~z:(-1.0) ();

  (* draw back face *)
  let z = -. width *. 0.5 in
  GlDraw.begins `quad_strip;
  for i=0 to teeth do
    vertex i ~r:r1 ~z;
    vertex i ~r:r0 ~z;
    vertex i ~r:r1 ~s:3 ~z;
    vertex i ~r:r0 ~z;
  done;
  GlDraw.ends ();

  (* draw back sides of teeth *)
  GlDraw.begins `quads;
  for i=0 to teeth - 1 do
    vertex i ~r:r1 ~s:3 ~z;
    vertex i ~r:r2 ~s:2 ~z;
    vertex i ~r:r2 ~s:1 ~z;
    vertex i ~r:r1 ~z;
  done;
  GlDraw.ends ();

  (* draw outward faces of teeth *)
  let z = width *. 0.5 and z' = width *. (-0.5) in
  GlDraw.begins `quad_strip;
  for i=0 to teeth - 1 do
    let angle = float i *. ta in
    vertex i ~r:r1 ~z;
    vertex i ~r:r1 ~z:z';
    let u = r2 *. cos(angle+.da) -. r1 *. cos(angle)
    and v = r2 *. sin(angle+.da) -. r1 *. sin(angle) in
    GlDraw.normal ~x:v ~y:(-.u) ();
    vertex i ~r:r2 ~s:1 ~z;
    vertex i ~r:r2 ~s:1 ~z:z';
    GlDraw.normal ~x:(cos angle) ~y:(sin angle) ();
    vertex i ~r:r2 ~s:2 ~z;
    vertex i ~r:r2 ~s:2 ~z:z';
    let u = r1 *. cos(angle +. 3. *. da) -. r2 *. cos(angle +. 2. *. da)
    and v = r1 *. sin(angle +. 3. *. da) -. r2 *. sin(angle +. 2. *. da) in
    GlDraw.normal ~x:v ~y:(-.u) ();
    vertex i ~r:r1 ~s:3 ~z;
    vertex i ~r:r1 ~s:3 ~z:z';
    GlDraw.normal ~x:(cos angle) ~y:(sin angle) ();
  done;
  vertex 0 ~r:r1 ~z;
  vertex 0 ~r:r1 ~z:z';
  GlDraw.ends ();

  GlDraw.shade_model `smooth;

  (* draw inside radius cylinder *)
  GlDraw.begins `quad_strip;
  for i=0 to teeth do
    let angle = float i *. ta in
    GlDraw.normal ~x:(-. cos angle) ~y:(-. sin angle) ();
    vertex i ~r:r0 ~z:z';
    vertex i ~r:r0 ~z;
  done;
  GlDraw.ends ()

class view area = object (self)
  val mutable gears = None
  val mutable view_rotx = 0.0
  val mutable view_roty = 0.0
  val mutable view_rotz = 0.0
  val mutable angle = 0.0

  method rotx a = view_rotx <- a
  method roty a = view_roty <- a
  method rotz a = view_rotz <- a

  method draw () =
    let (gear1, gear2, gear3) =
      match gears with Some x -> x
      | None -> failwith "draw : not yet initialized" in

    GlClear.clear [`color;`depth];

    GlMat.push ();
    GlMat.rotate ~angle:view_rotx ~x:1.0 ();
    GlMat.rotate ~angle:view_roty ~y:1.0 ();
    GlMat.rotate ~angle:view_rotz ~z:1.0 ();

    GlMat.push ();
    GlMat.translate ~x:(-3.0) ~y:(-2.0) ();
    GlMat.rotate ~angle:angle ~z:1.0 ();
    (* gear inner:1.0 outer:4.0 width:1.0 teeth:20 tooth_depth:0.7; *)
    GlList.call gear1;
    GlMat.pop ();

    GlMat.push ();
    GlMat.translate ~x:3.1 ~y:(-2.0) ();
    GlMat.rotate ~angle:(-2.0 *. angle -. 9.0) ~z:1.0 ();
    (* gear inner:0.5 outer:2.0 width:2.0 teeth:10 tooth_depth:0.7; *)
    GlList.call gear2;
    GlMat.pop ();

    GlMat.push ();
    GlMat.translate ~x:(-3.1) ~y:4.2 ();
    GlMat.rotate ~angle:(-2.0 *. angle -. 25.0) ~z:1.0 ();
    (* gear inner:1.3 outer:2.0 width:0.5 teeth:10 tooth_depth:0.7; *)
    GlList.call gear3;
    GlMat.pop ();

    GlMat.pop ();

    Gl.flush ();
    area#swap_buffers ()

  method idle () =
    angle <- angle +. 2.0;
    if area#misc#visible then self#draw ();
    true

  method reshape ~width:w ~height:h =
    GlDraw.viewport ~x:0 ~y:0 ~w ~h;
    GlMat.mode `projection;
    GlMat.load_identity ();
    let r = float w /. float h in
    let r' = 1. /. r in
    if (w>h) then
      GlMat.frustum ~x:(-. r,r) ~y:(-1.0,1.0) ~z:(5.0,60.0)
    else
      GlMat.frustum ~x:(-1.0,1.0) ~y:(-.r',r') ~z:(5.0,60.0);

    GlMat.mode `modelview;
    GlMat.load_identity();
    GlMat.translate ~z:(-40.0) ();
    GlClear.clear[`color;`depth]

  method init () =
    let pos = 5.0, 5.0, 10.0, 0.0
    and red = 0.8, 0.1, 0.0, 1.0
    and green = 0.0, 0.8, 0.2, 1.0
    and blue = 0.2, 0.2, 1.0, 1.0 in

    GlLight.light ~num:0 (`position pos);
    List.iter ~f:Gl.enable
      [`cull_face;`lighting;`light0;`depth_test;`normalize];

    (* make the gears *)
    let make_gear ~inner ~outer ~width ~teeth ~color =
      let list = GlList.create `compile in
      GlLight.material ~face:`front (`ambient_and_diffuse color);
      gear ~inner ~outer ~width ~teeth ~tooth_depth:0.7;
      GlList.ends ();
      list
    in
    let gear1 = make_gear ~inner:1.0 ~outer:4.0 ~width:1.0 ~teeth:20 ~color:red
    and gear2 = make_gear ~inner:0.5 ~outer:2.0 ~width:2.0 ~teeth:10 ~color:green
    and gear3 = make_gear ~inner:1.3 ~outer:2.0 ~width:0.5 ~teeth:10 ~color:blue in
    gears <- Some (gear1, gear2, gear3)

  initializer
    area#connect#realize ~callback: self#init;
    area#connect#display ~callback: self#draw;
    area#connect#reshape ~callback: self#reshape;
    ()
end

open GMain

let main () =
  let window = GWindow.window ~title: "ML Gears" () in
  window#connect#destroy ~callback:Main.quit;
  window#set_resize_mode `IMMEDIATE;

  let table = GPack.table ~rows: 2 ~columns: 3 ~packing: window#add () in

  let area = GlGtk.area [`DEPTH_SIZE 1; `RGBA; `DOUBLEBUFFER]
      ~width: 300 ~height: 300
      ~packing: (table#attach ~left: 1 ~top: 0 ~expand: `BOTH) () in

  let view = new view area in

  let scale ~orientation ~callback ~value ?packing () =
    let adjustment = GData.adjustment ~lower: 0.0 ~upper: 360.0 () in
    adjustment#connect#value_changed
      ~callback: (fun () -> callback adjustment#value);
    adjustment#set_value value;
    GRange.scale orientation ~adjustment ~draw_value: false ?packing ()
  in
  let sx = scale ~orientation: `VERTICAL ~callback: view#rotx  ~value: 40.0
      ~packing: (table#attach ~left: 2 ~top: 0 ~expand: `Y) () in
  let sy = scale ~orientation: `HORIZONTAL ~callback: view#roty ~value: 20.0
      ~packing: (table#attach ~left: 1 ~top: 1 ~expand: `X) () in
  let sz = scale ~orientation: `VERTICAL ~callback: view#rotz ~value: 10.0
      ~packing: (table#attach ~left: 0 ~top: 0 ~expand: `Y) () in

  Timeout.add ~ms: 20 ~callback: view#idle;
  window#show ();
  Main.main ()

let _ = Printexc.print main ()
