How to build latest version

Installed vanilla processing-2.2.1

Installed jruby (preferably 1.7.13)

jdk-1.7+

ruby-compiler gem

ideally wget

Clone this repo. Unless already configured, set processing root in .rp5rc (easy set using

SetProcessingRoot.pde, which is included in the samples directory). Required to enable auto-copy of core.jar to lib (for compiling), and for testing.
cd ruby-processing
rake builds extension, builds the gem and runs tests
gem install ruby-processing-2.5.0.gem
rp5 setup check pre-install (run again after)
rp5 setup install to download and install jruby-complete-1.7.13
From home directory rp5 unpack samples
cd samples
rake runs the contributed samples in a random order
rake shader to run shader samples
rake vecmath runs vecmath library
Should you wish to run the spec tests, they need to be run using jruby so

jruby -S rspec deglut_spec.rb for example