f3r / rubypong

Pong, in ruby

HASU

Hasu is a thin ruby gem that wraps and give us access to two game development libraries that help us build game easily. Chingu is an OpenGL accelerated 2D game framework for Ruby, and Gosu, that we are going to explore in a minute.

HASU AND GOSU

In order to use hasu, we must install gosu first. Gosu is a 2D game development library for the Ruby and C++ programming languages, available for Mac OS X, Windows, and Linux. The Ruby version works with MRI, MacRuby, and Rubinius, but not JRuby. Gosu only provides basic building blocks:

• a window with a main loop and callbacks
• 2D graphics and text, accelerated by 3D hardware
• sound samples and music in various formats
• keyboard, mouse, and gamepad input

Gosu is mostly in ruby, but has a C implementation for graphics, that requires your MacOS to have certain libraries for graphics, sound, etc. You can install them easily if you have HomeBrew, otherwise, you can install HomeBrew, because it's awesome.

  $ brew install sdl2 libogg libvorbis

  ==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/sdl2-2.0.3.mavericks.bottle.tar.gz
  ######################################################################## 100.0%
  ==> Pouring sdl2-2.0.3.mavericks.bottle.tar.gz
  🍺  /usr/local/Cellar/sdl2/2.0.3: 75 files, 3.9M
  ==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/libogg-1.3.2.mavericks.bottle.tar.gz
  ######################################################################## 100.0%
  ==> Pouring libogg-1.3.2.mavericks.bottle.tar.gz
  🍺  /usr/local/Cellar/libogg/1.3.2: 95 files, 672K
  ==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/libvorbis-1.3.4.mavericks.bottle.tar.gz
  ######################################################################## 100.0%
  ==> Pouring libvorbis-1.3.4.mavericks.bottle.tar.gz
  🍺  /usr/local/Cellar/libvorbis/1.3.4: 162 files, 2.7M

Now we can install the hasu gem with gem install:

  $ gem install hasu

  Building native extensions.  This could take a while...
  Successfully installed gosu-0.8.5
  Fetching: hasu-0.1.5.gem (100%)
  Successfully installed hasu-0.1.5
  Parsing documentation for gosu-0.8.5
  Installing ri documentation for gosu-0.8.5
  Parsing documentation for hasu-0.1.5
  Installing ri documentation for hasu-0.1.5
  Done installing documentation for gosu, hasu after 11 seconds
  2 gems installed

PHASES OF THE GAME

All games based on Gosu follow the same standard pattern:

  reset
  while game_is_running?
    update
    draw
  end

BASIC SETUP

Create your game

After adding the hasu module, we get access to Hasu. Your game will have to subclass Hasu::Window, which can give us initially:

• initialize: the constructor to create a window for the game
• .run: method that starts the game!

game.rb:

  require "hasu"

  class Name__Your__Game < Hasu::Window

    WIDTH       = 768
    HEIGHT      = 576

    def initialize
      super(WIDTH, HEIGHT, false)  # full-screen = false
    end

    def reset
      # ...
    end

    def update
      # ...
    end

    def draw
      # ...
    end
  end

  Name__Your__Game.run

And we can run it by typing in terminal:

  $ ruby game.rb

Pong

Create Actions

2: require your game's files

For the files you want to be hot loaded, use Hasu.load instead of require.

  Hasu.load "ball.rb"

3: Run your game with .run

Instead of Game.new.show, run your Hasu game with Game.run.

SETUP

Create Characters

  @player = ItalianPlumber.new
  @bad_guy = FireBreathingTurtle.new

Load configurations from file

  Map.load_from_file("castle.yml")

Save User Games

  load_saved_game("save3.json")

UPDATE

Previous State

  @player.y -= @player.y_vel
  @player.y_vel -= 9.8

Player Input

  if button_down?("A")
    @player.jump!
  end

Time

  if last_fire < Time.now -2
    breather_fire!
  end

Add Randomness

  item = [
    :fire_flower,
    :cape,
    :mushroom
  ].sample

  spawn(item)

RENDER

plumber_image.draw(
  @player.x,
  @player.y
)

Other interesting libraries

gem install gosu

complete with examples, precompiled for Windows (Ruby 1.8 & 1.9), needs an Apple compiler on OS X (usually Xcode)

gem install releasy

automatically distribute any Ruby game as a Windows executable or Mac app, by Spooner

gem install texplay

pixel-based drawing on Gosu images, by banister

gem install ashton

a C extension that integrates GL shaders and a particle engine with Gosu, also by Spooner

gem install gamebox

a complete game framework based on Gosu, by shawn42

gem install chingu

a library that adds more game logic, by ippa (not updated anymore)

gem install chipmunk

a popular physics library with an integration example in the wiki