Prototyping The Game - Developing Games With Ruby - page 47

15 GameState . switch( MenuState . instance)
16 $window . show

In our entry point we also have a small helper which will help loading images and sounds
using Game.media_path .

The rest is obvious: we create GameWindow instance and store it in $window variable, as
discussed before. Then we use GameState.switch) to load MenuState , and show
the game window.

Implementing Menu State
This is how simple MenuState implementation looks like:
03-prototype/states/menu_state.rb

1 require 'singleton'
2 class MenuState < GameState
3

include Singleton

attr_accessor :play_state 4

5
6 def initialize
7 @message = Gosu :: Image . from_text(

$window , "Tanks Prototype" , 8

Gosu . default_font_name, 100 ) 9

10 end
11
12 def enter
13 music . play( true )
14 music . volume = 1
15 end
16
17 def leave
18 music . volume = 0
19 music . stop
20 end
21
22 def music
23 @@music ||= Gosu :: Song . new(

$window , Game . media_path( 'menu_music.mp3' )) 24

25 end
26
27 def update
28 continue_text = @play_state ? "C = Continue, " : ""

@info = Gosu :: Image . from_text( 29