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Contents
########################################################
# A MPeano fractal implemented using a
# Lindenmayer System in ruby-processing by Martin Prout
########################################################
load_library 'grammar'
####################################################
# The MPeano fractal has been used to study the
# Euclidean travelling salesman problem
####################################################
class MPeano
include Processing::Proxy
SQRT2 = Math.sqrt(2.0)
ISQRT2 = 1/SQRT2
attr_reader :draw_length, :xpos, :ypos, :theta, :axiom, :grammar, :delta
def initialize(xpos, ypos)
@axiom = 'XFF--AFF--XFF--AFF' # Axiom
rules = {
'X' => '+!X!FF-BQFI-!X!FF+', # LSystem Rules
'F' => '', # Example of a 'delete' replace
'Y' => 'FFY',
'A' => 'BQFI',
'B' => 'AFF'
}
@grammar = Grammar.new(axiom, rules)
@delta = QUARTER_PI # 45 degrees
@theta = HALF_PI
@draw_length = 8
@xpos = xpos
@ypos = ypos
end
def generate(gen)
grammar.generate gen
end
def translate_rules(prod)
points = [] # An empty array to store line vertices
prod.each do |ch|
case(ch)
when 'F'
points << xpos << ypos << (@xpos -= draw_length * cos(theta)) << (@ypos -= draw_length * sin(theta))
when '+'
@theta += delta
when '-'
@theta -= delta
when '!'
@delta = -delta
when 'I'
@draw_length *= ISQRT2
when 'Q'
@draw_length *= SQRT2
when 'X', 'A', 'B'
else
puts("character '#{ch}' not in grammar")
end
end
return points
end
end
attr_reader :points
def setup
size(600, 600)
mpeano = MPeano.new(width / 2, height * 0.95)
production = mpeano.generate 7 # 7 generations looks OK
@points = mpeano.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