Contents

############################
# Simple lsystem grammar
############################
class Grammar
  def initialize(axiom, rules)
    @axiom = axiom
    @rules = rules
  end

  def expand(production, iterations, &block)
    production.each_char do |token|
      if @rules.has_key?(token) && iterations > 0 
        expand(@rules[token], iterations - 1, &block)
      else
        yield token
      end
    end
  end

  def each gen
    expand(@axiom, gen) {|token| yield token }
  end

  def generate gen
    output = []
    each(gen) { |token| output << token }
    output
  end

end


############################
# Hilbert Curves
###########################
class Hilbert
  include Processing::Proxy
  attr_reader :grammar, :axiom, :production, :premis, :rule,
  :theta, :distance, :phi, :gen, :adj_array

  def initialize(size: 1.0, gen: 1)
    @axiom = 'X'                                           # AXIOM
    @rule = {'X' => '^<XF^<XFX-F^>>XFX&F+>>XFX-F>X->'}     # RULE
    @gen = gen
    @grammar = Grammar.new(axiom, rule) 
    @production = grammar.generate gen
    @distance = size / (gen**2 - 1)
    @theta = 90.radians
    @phi = 90.radians  
    @adj_array = [0, 0.5, 1.5, 3.5, 7.5, 15].map { |x| Vec3D.new(x * -1, x, x * -1) }
  end

  def draw    
    adj = adj_array[gen] * distance
    translate(adj.x, adj.y, adj.z)
    fill(0, 75, 152)
    light_specular(204, 204, 204)
    specular(255, 255, 255)
    shininess(1.0)
    production.each do |ch|
      case(ch)
      when 'F'
        translate(0, distance / -2, 0)
        box(distance/9 , distance, distance/9)
        translate(0, distance / -2, 0)
      when '+'
        rotateX(-theta)
      when '-'
        rotateX(theta)
      when '>'
        rotateY(theta)
      when '<'
        rotateY(-theta)
      when '&'
        rotateZ(-phi)
      when '^'
        rotateZ(phi)
      when 'X'
      else
        puts("character '#{ch}' not in grammar")
      end
    end
  end
end   

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
ruby-processing-2.6.3	samples/processing_app/library/vecmath/vec3d/library/hilbert/hilbert.rb
ruby-processing-2.6.2	samples/processing_app/library/vecmath/vec3d/library/hilbert/hilbert.rb
ruby-processing-2.6.1	samples/processing_app/library/vecmath/vec3d/library/hilbert/hilbert.rb