Sha256: d8c3745177902c4496bf27e11123248bda3612276fff41f176d73d484a795f42
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Versions: 6
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Contents
####################################################
# The DavidTour fractal has been used to study the
# Euclidean travelling salesman problem
####################################################
load_library :grammar
class DavidTour
import 'grammar'
attr_reader :draw_length, :xpos, :ypos, :theta, :axiom, :grammar
DELTA = Math::PI/3 # 60 degrees
def initialize(xpos, ypos)
@axiom = 'FX-XFX-XFX-XFX-XFX-XF' # Axiom
@theta = 0
@grammar = Grammar.new(
axiom,
'F' => '!F!-F-!F!', # Rules
'X' => '!X'
)
@draw_length = 15
@xpos = xpos
@ypos = ypos
end
def create_grammar(gen)
@draw_length *= draw_length * 0.5**gen
grammar.generate(gen)
end
def translate_rules(prod)
swap = false
points = [] # An empty array to store lines as a flat array of points
prod.each do |ch|
case(ch)
when 'F'
points << xpos << ypos << (@xpos += draw_length * Math.cos(theta)) << (@ypos -= draw_length * Math.sin(theta))
when '+'
@theta += DELTA
when '-'
@theta += swap ? DELTA : -DELTA
when '!'
swap = !swap
when 'X'
else
puts("character '#{ch}' not in grammar")
end
end
return points
end
end
########################################################
# A David Tour fractal implemented using a
# Lindenmayer System in ruby-processing by Martin Prout
########################################################
attr_reader :points
def setup
size(800, 900)
david = DavidTour.new(width * 0.6, height/4)
production = david.create_grammar(5)
@points = david.translate_rules(production)
no_loop
end
def draw
background(0)
stroke(255)
points.each_slice(4) do |point|
line(*point)
end
end
Version data entries
6 entries across 6 versions & 1 rubygems