ドラゴン曲線

turtle_dragon_curve.rb

require 'oekaki'
require_relative 'turtle'

Width, Height = 600, 450

Oekaki.app width: Width, height: Height, title: "Dragon curve" do
  draw do
    clear
    
    depth = 12
    
    l = 350
    t = Turtle.new(Width, Height, self)
    t.color(0xf0ff, 0xffff, 0xffff)
    t.move(-l / 2, 50)
    
    drawing = lambda do |length, depth|
      if depth.zero?
        t.forward(length)
      else
        len = length / sqrt(2)
        po1 = t.pen_po
        t.forward(length, false)
        po2, t.pen_po = t.pen_po, po1
        t.right(45)
        drawing[len, depth - 1]
        t.pen_po = po2
        t.right(90)
        drawing[len, depth - 1]
        t.pen_po = po2
        t.left(135)
      end
    end
    
    drawing[l, depth]
  end
end