Space_Ruby.rb

require 'gosu'

module ZOrder
	BACKGROUND, STARS, PLAYER, UI = *0..3
end


class Tutorial < Gosu::Window
	def initialize
		super 640, 480
		self.caption = "Space Ruby"

		@background_image = Gosu::Image.new("media/space.png", :tileable => true)

		@player = Player.new
		@player.wrap(320, 240)

		@star_anim = Gosu::Image.load_tiles("media/star.png", 25, 25)
    	@stars = Array.new

    	@font = Gosu::Font.new(30)


	end

	def update
		 if Gosu.button_down?(Gosu::KbLeft) 
      		@player.turn_left
   		 end
	    
	    if Gosu.button_down?(Gosu::KbRight)
	     	@player.turn_right
	    end
	    
	    if Gosu.button_down?(Gosu::KbUp)
	     	@player.accelarate
	    end

	    if Gosu.button_down? (Gosu::KbDown)
	     	@player.accelarate
	    end

   		 @player.move
    	@player.collect_stars(@stars)

    	if rand(100) < 4 and @stars.size < 25
    		@stars.push(Star.new(@star_anim))
    	end
    end
  

	def draw
		@background_image.draw(0, 0, ZOrder::BACKGROUND)
		@player.draw
		@stars.each { |star| star.draw }
		@font.draw("Score: #{@player.score}", 10, 10, ZOrder::UI, 1.0, 1.0, Gosu::Color::GREEN)

	end

	def button_down(id)
		if id == Gosu::KbEscape
			close
		else
			super
		end		
	end
end





class Player
	attr_reader :score

	def initialize
		@image = Gosu::Image.new("media/starfighter.bmp")
		@beep = Gosu::Sample.new("media/beep.wav")
		@x = @y = @vel_x = @vel_y = @angle = 0.0
		@score = 0
	end

	def wrap(x, y)
		@x = x
		@y = y		
	end

	def turn_left
		@angle -= 4.5		
	end

	def turn_right
		@angle += 4.5		
	end

	def accelarate
		@vel_x += Gosu.offset_x(@angle, 0.5)
		@vel_y += Gosu.offset_y(@angle, 0.5)		
	end

	def move
		@x += @vel_x
		@y += @vel_y
		@x %= 640
		@y %= 480

		@vel_x *= 0.95
		@vel_y *= 0.95		
	end

	def draw
		@image.draw_rot(@x, @y, 1, @angle)		
	end

	def score
	    @score
	end

	def collect_stars(stars)
    stars.reject! do |star|
      if Gosu.distance(@x, @y, star.x, star.y) < 35
        @score += 10
        @beep.play
        true
      else
        false
      end
    end
  end
end



class Star
  attr_reader :x, :y

  def initialize(animation)
    @animation = animation
    @color = Gosu::Color::BLACK.dup
    @color.red = rand(256 - 40) + 40
    @color.green = rand(256 - 40) + 40
    @color.blue = rand(256 - 40) + 40
    @x = rand * 640
    @y = rand * 480
  end

  def draw  
    img = @animation[Gosu.milliseconds / 100 % @animation.size]
    img.draw(@x - img.width / 2.0, @y - img.height / 2.0,
        ZOrder::STARS, 1, 1, @color, :add)
  end
end



Tutorial.new.show