Setting Up an Impact.js Game Development Environment

by Kevin Thompson

June 26, 2013

For a number of years now I've wanted to create games. Actually, I've wanted to create my own games for about as long as I can remember. I've finally decided to try my hand at creating games for myself and my children, and after evaluating a number of game development frameworks, I've decided that Impact.js is the platform that, being a web developer, will be the easiest for me to adopt and actually create a game with.

Although there really isn't much to setting up an Impact.js development environment, there are a few things that I wanted to be able to do that would make building games with Impact.js feel more like my daily Ruby development.

Because Impact.js page require some sort of web server, I wanted them to work with my development server of choice, Pow. You can serve static files through Pow by simply moving your static files to (in this case the source of your Impact.js game) to a public folder, but I wanted a little more control over my the project routing. More specifically, I also didn't want to have to remember how to spell weltmeister.html so I wanted to be able to remap that URL.

To solve both of these issues, I decided to add a file to my project and use Rack::Rewrite to serve the static files, and also to remap /weltmeister.html to /edit. Below are the two files you need to create in order to duplicate my setup:

# ./Gemfile
source ''

# Rack
gem 'rack'
gem 'rack-legacy'
gem 'rack-rewrite'
# ./
require 'rubygems'
require 'rack'
require 'rack-legacy'
require 'rack-rewrite'

INDEXES = ['index.html','index.php']

use Rack::Rewrite do
  rewrite %r{^/edit$}, '/weltmeister.html'
  rewrite %r{(.*/$)}, lambda {|match, rack_env|
    return_path = rack_env['PATH_INFO']
    INDEXES.each do |index|
      if File.exists?(File.join(Dir.getwd, rack_env['PATH_INFO'], index))
        return_path = rack_env['PATH_INFO'] + index

use Rack::Legacy::Php, Dir.getwd
run Dir.getwd

Once you've created those two files, you'll need run bundle install in order to install the required gems. Now you just need to link your project to Pow (I'd recommend using the powder gem) and you should be able to access your impact game using pow (ex:

If you don't yet have PHP installed, you'll need to perform a few more steps in order to get the Weltmeister level editor working properly with this setup. Simply follow these instructions for installing PHP using Homebrew over on Github and you should be all set.

I'll continue posting about my experiences with Impact.js as I continue to explore, and I'd love to hear any tips or recommendations from other Impact.js developers.