split out into separate files

lib/enemy.rb

@@ -0,0 +1,19 @@
+class Enemy
+  def initialize(window)
+    @window = window
+    @image = Gosu::Image.new(window, "media/enemy.png", false)
+    @x = @y = @vel_x = @vel_y = @angle = 0.0
+  end
+
+  def update
+    @x += 1
+    @y += 1
+    if @x > @window.width || @y > @window.height
+      @window.enemies.delete(self)
+    end
+  end
+
+  def draw
+    @image.draw_rot(@x, @y, 1, @angle, 0.5, 0.5, 0.25, 0.25)
+  end
+end

lib/game.rb

@@ -1,5 +1,7 @@
 require 'rubygems'
 require 'gosu'
+require 'enemy'
+require 'tower'
 
 class GameWindow < Gosu::Window
   attr_reader :enemies
@@ -31,41 +33,6 @@ def button_down(id)
   end
 end
 
-class Enemy
-  def initialize(window)
-    @window = window
-    @image = Gosu::Image.new(window, "media/enemy.png", false)
-    @x = @y = @vel_x = @vel_y = @angle = 0.0
-  end
-
-  def update
-    @x += 1
-    @y += 1
-    if @x > @window.width || @y > @window.height
-      @window.enemies.delete(self)
-    end
-  end
-
-  def draw
-    @image.draw_rot(@x, @y, 1, @angle, 0.5, 0.5, 0.25, 0.25)
-  end
-end
-
-class Tower
-  # damage
-
-  def initialize(window)
-    @window = window
-    @image = Gosu::Image.new(window, "media/tower.png", false)
-    @x = rand(@window.width - 20) + 10
-    @y = @window.height - 60
-  end
-
-  def draw
-    @image.draw_rot(@x, @y, 1, 0)
-  end
-end
-
 # class Board
 # end
 

lib/tower.rb

@@ -0,0 +1,14 @@
+class Tower
+  # damage
+
+  def initialize(window)
+    @window = window
+    @image = Gosu::Image.new(window, "media/tower.png", false)
+    @x = rand(@window.width - 20) + 10
+    @y = @window.height - 60
+  end
+
+  def draw
+    @image.draw_rot(@x, @y, 1, 0)
+  end
+end