space_invaders_clone.rb

require 'gosu'
FONT_COLOR = 0xff_ffff00

class SpaceInvader < Gosu::Window
  def initialize
    super 640, 480
    self.caption = "Space Invaders"
    @message = Gosu::Font.new(20)
    coordinate_array = []
    i = 0
    11.times {coordinate_array << [i+=50, 140]}
    i = 0
    11.times {coordinate_array << [i+=50, 180]}
    i = 0
    11.times {coordinate_array << [i+=50, 220]}
    i = 0
    11.times {coordinate_array << [i+=50, 260]}
    i = 0
    11.times {coordinate_array << [i+=50, 300]}
    @invader_phalanx = []
    coordinate_array.each do |item|
      @invader_phalanx << Invader.new(item[0], item[1])
    end
    @text_message = ""
  end

  def update
    @invader_phalanx.each do |alien_ship|
      #this is where all the invader logic goes.
      alien_ship.move
    end
    close if Gosu::button_down?(Gosu::KbEscape)
  end

  def button_down(id)
  end

  def draw
    @message.draw("#{@text_message}", 10, 30, FONT_COLOR)
    @message.draw("W => 640 - H => 480", 425, 30, FONT_COLOR)
    @invader_phalanx.each {|item| item.draw if item.alive == true}
  end
end


class Invader
  attr_accessor :x, :y, :alive, :rotate
  def initialize(x, y)
    @x = x
    @y = y
    @sprite = Gosu::Image.new("media/invader.png")
    @alive = true
    @rotate = 0
  end

  def draw
#invader animation will go here.
    @sprite.draw_rot(@x, @y, 1, @rotate)
  end

#this collision method is different than the player one. This is the one I wrote myself
  def collision?(barrier_x, barrier_y)
       (barrier_x.between?(@x - 10, @x) and barrier_y.between?(@y, @y + 10)) || (barrier_x.between?(@x, @x + 10) && barrier_y.between?(@y - 10, @y)) || (barrier_x.between?(@x - 10, @x) &&  barrier_y.between?(@y - 10, @y)) || (barrier_x.between?(@x, @x + 10) && barrier_y.between?(@y, @y + 10))
  end

  def move
    #moves the invaders to the left
    @x -= 1
  end
end
window = SpaceInvader.new
window.show