Ruby gosu implementation of Cpnway's game of life

game_of_life.rb

require 'gosu'

ANIMATION_INTERVAL = 0.4

module GameOfLife
  class Cell
    attr_accessor :x, :y

    def initialize(hash)
      raise 'Bad attribute keys' unless (hash.keys - [:x, :y, :alive]).empty?
      hash.each { |k,v| eval "@#{k}= #{v}" }
    end

    def alive?;       @alive;         end
    def alive=(bool); @alive = bool;  end
    def kill!;        @alive = false; end
    def resurrect!;   @alive = true   end

    def to_s
      alive? ? "\e[1;32mO\e[0m" : "\e[1;30mX\e[0m"
    end
  end

  class Grid < Array
    def initialize(x,y=x)
      if x.is_a? String
        super x.lines.map { |l| l.chomp.split '|' }
        .transpose
        .map.with_index do |col, x|
          col.map.with_index { |cell, y| GameOfLife::Cell.new(x: x, y: y, alive: !!(cell =~ /o/i)) }
        end
      else
        super(x) do |x|
          Array.new(y) do
            GameOfLife::Cell.new(alive: [true,false].sample, x: x, y: y)
          end
        end
      end
    end

    def next!
      cells, cells_to_kill, cells_to_resurrect = [], [], []

      each_cell do |cell|
        cells << [cell, around(cell).flatten.compact.count(&:alive?)]
      end

      # Any live cell with fewer than two live neighbours dies, as if caused by under-population.
      cells_to_kill.concat cells.select { |cell,ln| cell.alive? and ln < 2 }
      # Any live cell with two or three live neighbours lives on to the next generation.
        # Do nothing...
      # Any live cell with more than three live neighbours dies, as if by overcrowding.
      cells_to_kill.concat cells.select { |cell,ln| cell.alive? and ln > 3 }
      # Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
      cells_to_resurrect.concat cells.select { |cell,ln| !cell.alive? and ln == 3 }

      cells_to_kill.each      { |cell,_| cell.kill! }
      cells_to_resurrect.each { |cell,_| cell.resurrect! }

      self
    end

    def next; dup.next!; end

    def animate!(gens=Float::Infinity)
      print
      puts (['-']*first.size).join('-')
      gens.times do
        next!
        print
        puts (['-']*first.size).join('-')
        sleep(ANIMATION_INTERVAL)
      end
    end

    def animate(*args)
      dup.animate! *args
    end

    NEGATIVE_SLICE = ->(ary,i){ ((0..ary.size-1).to_a*2)[ary.size+i,3] }
    OVER_SLICE = ->(ary,i){ ((0..ary.size-1).to_a*2)[i%ary.size,3] }
    SLICE_AROUND = ->(ary,i) do
      return Array.new(3,nil) if ary.nil?
      if i <= 0
        NEGATIVE_SLICE[ary,i-1]
      elsif i >= ary.size-1
        OVER_SLICE[ary,i-1]
      else
        ((i-1)..(i+1)).to_a
      end
    end

    def around(x,y=nil)
      x, y = x.x, x.y if %w(x y).map { |m| x.respond_to? m }.all?
      ary = SLICE_AROUND[self,x].map do |xi|
        SLICE_AROUND[self[xi],y].map do |yi|
          self[xi][yi]
        end
      end
      ary[1][1] = nil
      self.class[*ary]
    end

    def each_cell
      each do |col|
        col.each do |cell|
          yield cell
        end
      end
    end

    def expand(cols=0,rows=cols)
      tmp_heigth, tmp_width = heigth, width
      cols.times do |x|
        self << Array.new(tmp_heigth) { |y| GameOfLife::Cell.new(x: tmp_width+x, y: y, alive: false) }
      end

      tmp_heigth, tmp_width = heigth, width
      each.with_index do |col,x|
        rows.times do |y|
          col << GameOfLife::Cell.new(x: x, y: tmp_heigth+y, alive: false)
        end
      end

      self
    end

    def to_s
      self.transpose.map do |row|
        row.map { |cell| cell.nil? ? '+' : cell.to_s }.join('|')
      end.join("\n")
    end

    def heigth; first.size;     end
    def width;  size;           end
    def print;  puts self.to_s; end
  end

  class Window < Gosu::Window
    TOP_COLOR = Gosu::Color.new(0xFFFeee)
    BOTTOM_COLOR = Gosu::Color.new(0xFF1D4DB5)

    def initialize(grid)
      @grid =  grid
      @width = @grid.size*30+5
      @heigth = @grid.first.size*30+5
      super @width, @heigth, false
      self.caption = 'Game of Life'
      @last_frame = Gosu::milliseconds
    end

    def update
      @grid.next!
      @this_frame = Gosu::milliseconds
      @delta = @this_frame - @last_frame
      @last_frame = @this_frame
      sleep ANIMATION_INTERVAL
    end

    def draw
      ## BACKGROUND
      draw_quad(
        0,      0,       TOP_COLOR,
        @width, 0,       TOP_COLOR,
        0,      @heigth, BOTTOM_COLOR,
        @width, @heigth, BOTTOM_COLOR
      )

      ## CELLS
      @grid.each_cell do |cell|
        color = cell.alive? ? Gosu::Color::GREEN : Gosu::Color::BLACK
        draw_quad(
          cell.x*30+5,  cell.y*30+5,  color,
          cell.x*30+30, cell.y*30+5,  color,
          cell.x*30+5,  cell.y*30+30, color,
          cell.x*30+30, cell.y*30+30, color
        )
      end
    end
  end
end

PULSAR = GameOfLife::Grid.new <<-GRID
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|X|X|O|O|O|X|X|X|O|O|O|X|X|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|X|X|O|O|O|X|X|X|O|O|O|X|X|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|X|X|O|O|O|X|X|X|O|O|O|X|X|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|O|X|X|X|X|O|X|O|X|X|X|X|O|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|X|X|O|O|O|X|X|X|O|O|O|X|X|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
  X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X|X
GRID

GameOfLife::Window.new(PULSAR).show

This scripts requires Gosu. Basically, you need to install some dependencies in order to be able to build native extensions for gosu. Them just gem install it.

In mac I just did:

brew install sdl2
gem install gosu

In linux:

# Gosu's dependencies for both C++ and Ruby
sudo apt-get install build-essential libsdl2-dev libsdl2-ttf-dev libpango1.0-dev \
                     libgl1-mesa-dev libfreeimage-dev libopenal-dev libsndfile-dev

# To install Ruby - if you are using rvm or rbenv, please skip this step
sudo apt-get install ruby-dev

# If you are using rvm or rbenv, do not use 'sudo'
sudo gem install gosu

Then dowload this file and run it ruby game_of_life.rb.