game

game.rb

require 'drawille'

class Ceil < Struct.new(:x, :y, :state)

  def alive?
    state == 1
  end
end


class World
  attr_accessor :x, :y, :ceils

  def print
    canvas = Drawille::Canvas.new
    ceils.each do |cell|
      canvas.set(cell.x, cell.y) if cell.alive?
    end
    puts canvas.frame
  end

  def fill
    0.upto(x) do |i|
      0.upto(y) do |j|
        set_ceil(Ceil.new(i, j, rand(2)))
      end
    end
  end

  def initialize(x, y)
    @x = x
    @dim = Array.new(x*y)
    @y = y
    @ceils = []
  end

  def set_ceil(ceil)
    @ceils << ceil
    @dim[ceil.x*x + ceil.y] = ceil
  end

  def ceil(x,y)
    return nil if (x<0 || y < 0 || x > @x || y > @y)
    @dim[x*@x + y]
  end

  def neigbors(ceil)
    x = ceil.x
    y = ceil.y

     [
       ceil(x-1, y-1),
       ceil(x,   y-1),
       ceil(x+1, y-1),
       ceil(x-1, y),
       ceil(x+1, y),
       ceil(x-1, y+1),
       ceil(x,   y+1),
       ceil(x+1, y+1),
     ].compact
  end
end

def evolute(world)
  new_world = World.new(world.x, world.y)

  world.ceils.each do |ceil|
    new_ceil = evolute_ceil(world, ceil)
    new_world.set_ceil(new_ceil)
  end
  new_world
end

def evolute_ceil(world, ceil)
  neigbors = world.neigbors(ceil)
  count_alive = neigbors.select(&:alive?).count
  state =
    case
    when count_alive < 2 then 0
    when (count_alive == 2 || count_alive == 3) && ceil.alive? then 1
    when count_alive > 3 && ceil.alive? then 0
    when (count_alive == 3) && !ceil.alive? then 1
    end
  Ceil.new(ceil.x, ceil.y, state)
end

world = World.new(140, 240)
world.fill

while true
  world = evolute(world)
  system("clear")
  world.print
end