open Graphics ;;
open_graph "" ;;

type point_float = 
    {mutable x : float ;
     mutable y : float } ;;

let point = {x = 0.0 ; y = 0.0} ;;

let point_courant_float () = (point.x, point.y) ;;

let moveto_float x_float y_float =
  moveto (int_of_float x_float) (int_of_float y_float) ;
  point.x <- x_float ;
  point.y <- y_float;;

let lineto_float x_float y_float =
  lineto (int_of_float x_float) (int_of_float y_float) ;
  point.x <- x_float ;
  point.y <- y_float ;;
 
let avance distance angle =
  let (x_courant_float, y_courant_float) = point_courant_float () in
  let x_cible_float = x_courant_float +. distance *. (cos angle)
  and y_cible_float = y_courant_float +. distance *. (sin angle) in
  lineto_float x_cible_float y_cible_float ;;

let pi = 3.1415926535 ;;

let pi_sur_trois = pi /. 3. ;;

let rec motif generation distance angle = match generation with
  0 -> avance distance angle
| n -> let nouvelle_distance = distance /. 3. in
           motif (n-1) nouvelle_distance angle ;
           motif (n-1) nouvelle_distance (angle +. pi_sur_trois) ;
           motif (n-1) nouvelle_distance (angle -. pi_sur_trois) ;
           motif (n-1) nouvelle_distance angle ;;

let flocon n distance =
  clear_graph() ;
  moveto_float 10. (distance /. 3.) ;
  motif n distance pi_sur_trois ;
  motif n distance (-. pi_sur_trois) ;
  motif n distance (-. pi) ;; 

clear_graph();;
moveto_float 10. 10.;;
motif 0 300. 0.;;
moveto_float 10. 50.;;
motif 1 300. 0.;
moveto_float 10. 150.;;
motif 2 300. 0.;;
moveto_float 10. 250.;;
motif 3 300. 0.;;
moveto_float 10. 350.;;
motif 4 300. 0.;;
moveto_float 395. 10. ;;
motif 5 300. (pi /. 2.);;
moveto_float 490. 10. ;;
motif 6 300. (pi /. 2.);;
moveto_float 580. 10. ;;
motif 7 300. (pi /. 2.);;
 

  while not(key_pressed()) do
   ()
 done;;