gosugol.rb

require 'gosu'

class Tutorial < Gosu::Window
  def initialize(board_width, board_height, pattern_file)
    @board_width = board_width
    @board_height = board_height

    @columns = board_width / 12
    @rows = board_height / 12
    super @board_width, @board_height, update_interval: 100
    self.caption = "Game of life"
    @back_ground_color = Gosu::Color.argb(0xff_808080)
    @white = Gosu::Color.argb(0xff_ffffff)
    @black = Gosu::Color.argb(0xff_000000)
    pattern = pattern_file.to_s.empty? ? random_pattern : read_pattern(pattern_file)
    @pattern = prefill_pattern(pattern)

  end

  def read_pattern(file)
    lines = Array.new
    File.open(file).each do |line|
      line.chomp!
      next if line.empty? || line =~ /#/
      lines << line.split('').map {|x| (x.ord % 7 == 0) || (x.ord == 88) ? 1 : 0}
    end
    lines
  end

  def update
    tmp_pattern = Array.new(@columns * 2) {Array.new(@rows * 2, 0)}
    (@columns * 2).times do |x|
      (@rows * 2).times do |y|
        number_of_neighbours = neighbour_count(x, y)
        if @pattern[x][y] == alive && (number_of_neighbours == 2 || number_of_neighbours == 3)
          tmp_pattern[x][y] = alive
        elsif @pattern[x][y] == dead && (number_of_neighbours == 3)
          tmp_pattern[x][y] = alive
        else
          tmp_pattern[x][y] = dead
        end
      end
    end
    @pattern = tmp_pattern
  end

  def neighbour_count(x, y)
    anyone_there(x - 1, y - 1) + anyone_there(x - 1, y) + anyone_there(x - 1, y + 1) +
        anyone_there(x, y - 1) + anyone_there(x, y + 1) +
        anyone_there(x + 1, y - 1) + anyone_there(x + 1, y) + anyone_there(x + 1, y + 1)
  end

  def anyone_there(x, y, pattern = @pattern)
    (x < 0 || y < 0) ? 0 : pattern[x][y].to_i rescue 0
  end

  def alive
    1
  end

  def dead
    0
  end

  def generate_pattern
    array = Array.new(@columns * 2) {Array.new(@rows * 2, 0)}
    x = 0
    while x < @columns do
      y = 0
      while y < @rows do
        array[x][y] = yield(x, y)
        y = y + 1
      end
      x = x + 1
    end
    array
  end

  def prefill_pattern(pattern)
    generate_pattern {|x, y| anyone_there(x, y, pattern)}
  end

  def random_pattern
    generate_pattern {|x, y| rand(2)}
  end

  def draw
    draw_quad(
        0, 0, @back_ground_color,
        @board_width, 0, @back_ground_color,
        0, @board_height, @back_ground_color,
        @board_width, @board_height, @back_ground_color,
        0
    )
    x = 0
    while x < @rows do
      y = 0
      while y < @columns do
        life = @pattern[x][y]
        color = life == alive ? @black : @white
        draw_rect(y * 12, x * 12, 10, 10, color)
        y = y + 1
      end
      x = x + 1
    end
  end
end

t = Tutorial.new(640, 480, ARGV[0])

t.show