Mokkosuでマンデルブロ集合を描画してみた

研究室の先輩が作ったプログラム言語Mokkosuで
マンデルブロ集合を描画するプログラムを作りました。

#スクリーンショット
![mandel.png]
(https://qiita-image-store.s3.amazonaws.com/0/70577/7e3b31ae-2435-18c4-3125-e72f1338bb23.png)

#ソースコード

include "Graphics.mok";

let window_size = 500;
let x = ~-. 0.740425 -. 0.3;
let y = 0.113265 +. 0.12;
let w = 0.5;
let iteration = 500;

let judge_mandel c =
  fun loop z count = 
    if count > iteration -> ~- 1 else 
    if pow (fst z) 2.0 +. pow (snd z) 2.0 > 2.0 -> count else 
    let zr = pow (fst z) 2.0 -. pow (snd z) 2.0 +. fst c in
    let zi = 2.0 *. (fst z) *. (snd z) +. snd c in  
    let next_z = (zr, zi) in
    loop (next_z) (count + 1)
  in
  loop (0.0, 0.0) 0;
  
let draw_mandel gr =
  let h = window_size / 2 in
  (for i <- ~-h .. h in
    let cr = w *. (int_to_double i) /. (int_to_double h) +. x in
    for j <- ~-h .. h in 
      let ci = w *. (int_to_double j) /. (int_to_double h) +. y in
      let judge = judge_mandel (cr, ci) in
      if (judge == ~- 1) -> ()
      else 
      let color = 360.0 *. pow ((int_to_double judge) /. (int_to_double iteration)) 0.33 in
      let h = color in
      let s = 0.60 in
      let v = 0.90 in
      let pixel_x = window_size / 2 + i in
      let pixel_y = window_size / 2 - j in
      let (r, g, b) = hsv_to_rgb h s v in
      draw_pixel gr r g b pixel_x pixel_y) |> ignore;
  
do scene "main" {
  ~Draw(gr) -> do
     draw_mandel gr;
   end;
  _ -> ();
};

do set_size window_size window_size;

do show_window "main";