Using Ruby for Sega Dreamcast development

2025-08-07T21:09:50Z

SiZiOUS: Major upgrade as mruby is now officially supported as kos-port.

It is possible to develop in [https://www.ruby-lang.org Ruby] for the Sega Dreamcast system using the [https://mruby.org/ mruby implementation]. This support was originally introduced by [[Yuji Yokoo]] in 2019.

Like most Sega Dreamcast software, this project uses [[KallistiOS]] (KOS) as its base.

'''Note:''' Debugging support has not been tested as of 2025.

== Prerequisites ==

* A working [[KallistiOS]] environment must be set up, including all necessary dependencies for building KallistiOS;
* You must build the [[KallistiOS]] library;
* You must have both ''ruby'' and ''bison'' installed (see the sections below).

=== Installing prerequisites on Cygwin ===

Launch the Cygwin setup utility, search for the ''ruby'' and ''bison'' packages, and install them.

=== Installing prerequisites on DreamSDK ===

Depending on the underlying environment installed with [[DreamSDK]], there are 2 possible cases:

==== If you are using the modern MinGW-w64/MSYS2 foundation ====

No additional prerequisites are required — both Ruby and Bison are already preinstalled.

==== If you are using the legacy MinGW/MSYS foundation ====

Install manually the prerequisites:
* Install [https://rubyinstaller.org/ RubyInstaller], and ensure that the ''ruby'' command is available in your system ''PATH'';
* Use the '''MinGW Installation Manager''' to install the ''msys-bison-bin'' package.

'''Note:''' If you are using DreamSDK on Windows XP, you should install Ruby version 2.0.0 from [https://rubyinstaller.org/ RubyInstaller], as it is the last version compatible with that operating system.

=== Installing prerequisites on GNU/Linux ===

Use your distribution’s package manager to install the ''ruby'' and ''bison'' packages (e.g., run ''apt install ruby bison'' on Debian/Ubuntu).

=== Installing prerequisites on macOS ===

Install the ''ruby'' and ''bison'' packages using your preferred package manager (e.g., ''brew'').

=== Installing prerequisites on MinGW-w64/MSYS2 ===

Run the following command in the MSYS2 shell:

pacman -S ruby bison

== Setting up mruby ==

The recommended way to use mruby on Dreamcast is to install the '''mruby''' port from the [https://github.com/KallistiOS/kos-ports KallistiOS Ports repository].

First of all, make sure to clone the kos-ports repository:
cd /opt/toolchains/dc
git clone https://github.com/KallistiOS/kos-ports.git .

Then, run the following commands:

cd /opt/toolchains/dc/kos-ports/mruby
make install clean

This will build the embedded mruby library (''libmruby.a'') along with the required host tools (mainly ''/opt/toolchains/dc/bin/mrbc'') for the Dreamcast platform.

'''Note:''' The configuration file is stored in ''build_config/dreamcast_shelf.rb'' in the [https://github.com/mruby/mruby mruby] official repository.

== Using mruby in a Sega Dreamcast project ==

Two example projects are included with [[KallistiOS]] in the ''/examples/dreamcast/mruby'' directory:

* '''dreampresent''' – A simple presentation tool (this needs the ''libpng'' port as well);
* '''mrbtris''' – A sample game.

These examples were originally developed by [[Yuji Yokoo]] and correspond to the earlier stand-alone repositories. You can build them using the standard ''make'' command (assuming '''mruby''' and any additional required ports are properly installed via kos-ports).

dreamcast.wiki - User contributions [en]

Using Ruby for Sega Dreamcast development