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

(* $Id$ *)

open StdLabels

(*  Initialize material property and light source.
 *)
let myinit () =
  let light_ambient = 0.0, 0.0, 0.0, 1.0
  and light_diffuse = 1.0, 1.0, 1.0, 1.0
  and light_specular = 1.0, 1.0, 1.0, 1.0
  (*  light_position is NOT default value	*)
  and light_position = 1.0, 1.0, 1.0, 0.0
  in
  GlLight.light ~num:0 (`ambient light_ambient);
  GlLight.light ~num:0 (`diffuse light_diffuse);
  GlLight.light ~num:0 (`specular light_specular);
  GlLight.light ~num:0 (`position light_position);
  
  GlFunc.depth_func `less;
  List.iter ~f:Gl.enable [`lighting; `light0; `depth_test]

let pi = acos (-1.)

let solid_torus ~inner ~outer =
  let slices = 32 and faces = 16 in
  let slice_angle = 2.0 *. pi /. float slices
  and face_angle = 2.0 *. pi /. float faces in
  let vertex ~i ~j =
    let angle1 = slice_angle *. float i
    and angle2 = face_angle *. float j in
    GlDraw.normal3 (cos angle1 *. cos angle2,
		    -. sin angle1 *. cos angle2,
		    sin angle2);
    GlDraw.vertex3
      ((outer +. inner *. cos angle2) *. cos angle1,
       -. (outer +. inner *. cos angle2) *. sin angle1,
       inner *. sin angle2)
  in
  GlDraw.begins `quads;
  for i = 0 to slices - 1 do
    for j = 0 to faces - 1 do
      vertex ~i ~j;
      vertex ~i:(i+1) ~j;
      vertex ~i:(i+1) ~j:(j+1);
      vertex ~i ~j:(j+1);
    done
  done;
  GlDraw.ends ()

let solid_cone ~radius ~height =
  GluQuadric.cylinder ~base:radius ~top:0. ~height ~slices:15 ~stacks:10 ()

let solid_sphere ~radius =
  GluQuadric.sphere ~radius ~slices:32 ~stacks:32 ()

let display area =
  GlClear.clear [`color; `depth];

  GlMat.push ();
  GlMat.rotate ~angle:20.0 ~x:1.0 ();

  GlMat.push ();
  GlMat.translate ~x:(-0.75) ~y:0.5 ();
  GlMat.rotate ~angle:90.0 ~x:1.0 ();
  solid_torus ~inner:0.275 ~outer:0.85;
  GlMat.pop ();

  GlMat.push ();
  GlMat.translate ~x:(-0.75) ~y:(-0.5) (); 
  GlMat.rotate ~angle:270.0 ~x:1.0 ();
  solid_cone ~radius:1.0 ~height:2.0;
  GlMat.pop ();

  GlMat.push ();
  GlMat.translate ~x:0.75 ~z:(-1.0) (); 
  solid_sphere ~radius:1.0;
  GlMat.pop ();

  GlMat.pop ();
  Gl.flush ();
  area#swap_buffers ()

let my_reshape ~width:w ~height:h =
  GlDraw.viewport ~x:0 ~y:0 ~w ~h;
  GlMat.mode `projection;
  GlMat.load_identity ();
  if w <= h then
    GlMat.ortho ~x:(-2.5,2.5) ~z:(-10.0,10.0)
      ~y:(-2.5 *. float h /. float w, 2.5 *. float h /. float w)
  else 
    GlMat.ortho ~y:(-2.5,2.5) ~z:(-10.0,10.0)
      ~x:(-2.5 *. float w /. float h, 2.5 *. float w /. float h);
  GlMat.mode `modelview

(*  Main Loop
 *  Open window with initial window size, title bar, 
 *  RGBA display mode, and handle input events.
 *)

open GMain

let main () =
  let w = GWindow.window ~title:"Scene" () in
  w#connect#destroy ~callback:(fun () -> Main.quit (); exit 0);
  let area = GlGtk.area [`RGBA;`DEPTH_SIZE 1;`DOUBLEBUFFER]
      ~width:500 ~height:500 ~packing:w#add () in
  area#connect#realize ~callback:myinit;
  area#connect#reshape ~callback:my_reshape;
  area#connect#display ~callback:(fun () -> display area);
  area#event#add [`BUTTON_PRESS];
  area#event#connect#button_press ~callback:
    begin fun ev ->
      let p = (GdkEvent.Button.x ev, GdkEvent.Button.y ev, 0.) in
      area#make_current ();
      let (x, y, z) = GluMat.unproject p in
      Printf.printf "x=%f, y=%f, z=%f\n" x y z;
      flush stdout;
      true
    end;
  w#show ();
  Main.main ()

let _ = Printexc.print main ()
