Contents

# Mandelbrot Set example
# by Jordan Scales (http://jordanscales.com)
# 27 Dec 2012


# default size 900x600
# no need to loop
def setup
  size 900, 600
  no_loop
end

# main drawing method
def draw
  (0..900).each do |x|
    (0..600).each do |y|
      c = Complex.new(map(x, 0, 900, -3, 1.5), map(y, 0, 600, -1.5, 1.5))
  
      # mandel will return 0 to 20 (20 is strong)
      #   map this to 0, 255 (and flip it)
      set(x, y, color(255 - map(mandel(c,20), 0, 20, 0, 255).to_i))
    end
  end
end

# calculates the "accuracy" of a given point in the mandelbrot set
#    : how many iterations the number survives without becoming chaotic
def mandel(z, max = 10)
  score = 0
  c = z.clone
  while score < max do
    # z = z^2 + c
    z.square
    z.add c
    break if z.abs > 2

    score += 1
  end

  score
end


# rolled my own Complex class
#   stripped of all functionality, except for what I needed (abs, square, add, to_s)
#   
#   Using this class, runs in ~12.5s on my MacBook Air
#     compared to ~22s using ruby's Complex struct
class Complex

  attr_accessor :real, :imag

  def initialize(real, imag)
    @real = real
    @imag = imag
  end

  # squares a complex number - overwriting it
  def square
    r = real * real - imag * imag
    i = 2 * real * imag

    @real = r
    @imag = i
  end

  # adds a given complex number
  def add(c)
    @real += c.real
    @imag += c.imag
  end

  # computes the magnitude
  def abs
    sqrt(real * real + imag * imag)
  end

  def to_s
    "#{real} + #{imag}i"
  end

end

Version data entries

9 entries across 9 versions & 1 rubygems

Version	Path
ruby-processing-2.6.2	samples/contributed/mandelbrot.rb
ruby-processing-2.6.1	samples/contributed/mandelbrot.rb
ruby-processing-2.6.0	samples/contributed/mandelbrot.rb
ruby-processing-2.5.1	samples/contributed/mandelbrot.rb
ruby-processing-2.5.0	samples/contributed/mandelbrot.rb
ruby-processing-2.4.4	samples/contributed/mandelbrot.rb
ruby-processing-2.4.3	samples/contributed/mandelbrot.rb
ruby-processing-2.4.2	samples/contributed/mandelbrot.rb
ruby-processing-2.4.1	samples/contributed/mandelbrot.rb