AniRuby

Make sprite animations on Gosu, simply and easily.

Summary

This library will provide you with a nice n easy interface to do sprite animations on Gosu, while being as nifty and simple as possible.

The library is made in pure Ruby with no dependencies at all (except Gosu, of course) so it's quite lightweight.

Install

You can install the gem with the following command:

gem install aniruby

or use it with a bundle:

# Somewhere in your Gemfile

gem 'aniruby'

Getting Started

The smallest example:

require 'gosu'
require 'aniruby'

class MyWindow < Gosu::Window
  def initialize
    super(800, 600, false)

    @animation = AniRuby::Animation.new('my_spritesheet.png', 32, 32,
                                        0.15, retro: false, loop: true)
  end

  def update
    # Remember to update your animation!
    @animation.update
  end

  def draw
    @animation.draw(0, 0)
  end
end

Explanation

When you create a animation, you'll need to have an spritesheet, where you have each sprite of the animation, that's the first argument to Animation#new, then you'll need the dimensions of each individual sprite on your spritesheet, in the example provided we assume each sprite in the spritesheet is 32x32. Take for example the following spritesheet courtesy of penzilla on Itch.io

when we load it, it'll be divided into different image based on the individual dimensions of each sprite, so if we specify 32 as width and 32 as height then the spritesheet will be divided like this:

That's the bare minimum to get an animation, of course you can enable Gosu's retro option so pixel animations will still look crisp when scaled, enable looping or specify the duration of the animation (or for every frame even!).

In the example above we initialize the animation with retro off, looping on and with a duration of 0.15 (150ms) for every frame. So we'll get something like this:

Ain't that nice?

Drawing

You can draw an animation like any other Gosu::Image! An animation has both Animation#draw and Animation#draw_rot, these methods mimic the ones on Gosu, so you don't have to learn anything new.

Extras

Each Animation has extra helpful methods, like pause & unpause, reset, done?, etc. I recommend you to look on the source, its pretty small and easy to understand, or build the YARD documentation with:

rake doc

Development

Setup

First clone this repo locally:

git clone https://github.com/Chadowo/aniruby

Next you'll need to install the development dependencies of this gem with bundle install, Then you can use rake to build or test the gem.

Testing

Minitest is used to unit test this gem. To run the tests just call rake.

Roadmap

• more fine-grained control of animation
• being able to make an animation stitching Gosu::Image's together
• mirroring
• inverse animation
• multiple animation from a single spritesheet

License

This library is licensed under the MIT license.