The only OpenSimplex implementation I could find in C was adapted by @smcameron.

This gem is a mere attempt at exposing his work to the ruby community.

As there is no test coverage yet, use it at your own risk.

After cloning the repository, you can test that the extension was properly compiled:

git clone ...
bundle
rake compile
bundle exec irb -Ilib:ext -r osimplex

Then, from the IRB shell:

OSimplex::Generator.new(123).get_3d 42, 42, 42
 => 0.17865485575013934

You could also directly reference the gem from your Gemfile:

gem 'osimplex', github:   'hickscorp/osimplex'