mrbtris: Sample game for Sega Dreamcast written in Ruby

mrbtris is a simple game for the Sega Dreamcast which is written in Ruby as an proof-of-concept of using the mruby implementation on the Sega Dreamcast. This project was written by @yujiyokoo.

This project is built on the top of KallistiOS (KOS), which is the low-level library used to interact with the Sega Dreamcast hardware. Usually, programs written for the Sega Dreamcast are in C/C++, this project aims to demonstrate the use of Ruby source code targeting the Sega Dreamcast.

This project aims to provide a simple example of how to use KallistiOS (KOS) API and mruby together.

Demonstration

Below you may find a video of this game running on the real hardware (early version):

TODO

• Make an mrbgem for the Dreamcast specific things
• Create unit tests
• Use more Sega Dreamcast features

Building

mrbtris uses KallistiOS (KOS) and mruby as dependencies. For building this program you have two options:

• Using a working KallistiOS setup;
• Use the provided Docker image below.

Using your working KallistiOS environment

If you have a working KallistiOS environment, you will have to install the rake and bison packages (e.g. using apt, brew or pacman). If you are using DreamSDK, you will have to install the RubyInstaller package separately, in that case, rake should be available in the PATH environment variable.

Install mruby:

cd /opt
git clone https://github.com/mruby/mruby.git
cd /opt/mruby
make MRUBY_CONFIG=dreamcast_shelf

These commands will produces all the necessary files for using mruby on Sega Dreamcast. After that, just navigate to the mrbtris directory then enter make. This will produces the mrbtris.elf binary file.

Note: You may consult this page for reference.

Using Docker image

The Docker image is named mruby-kos-dc which is built from docker-mruby-kos-dc. The instruction to input are:

git clone https://gitlab.com/yujiyokoo/mrbtris-dreamcast.git
cd mrbtris-dreamcast
docker pull yujiyokoo/mruby-kos-dc
docker run -i -t -v $(pwd):/mnt yujiyokoo/mruby-kos-dc bash -c 'cd /mnt && . /opt/toolchains/dc/kos/environ.sh && make'

This should produce an elf binary called mrbtris.elf.

Running

Dreamcast emulator: Lxdream

To check that it at least runs, you can use Dreamcast emulators. In my experience, lxdream can boot elf and seems to work well enough to check it runs, but text display doesn't seems to render properly. You could still check that it boots up even without text. To do that, run lxdream -e mrbtris.elf or lxdream mrbtris.elf, depending on your lxdream version, from your Terminal.

Unfortunately, running on the real hardware has been the only way for me to test text display and actual performance, but it may be different in your environment.

Making a bootable image

If you want to try this software in your real Dreamcast and/or in an another emulator (like Demul, Redream, Reicast...), you may create a Padus DiscJuggler (cdi) image. For example, if you are using DreamSDK, you may do the following:

make dist	
makedisc mrbtris.cdi cd_root

This will produces the mrbtris.cdi image file that you may burn onto a CD-R or use in a Dreamcast emulator. Alternatively, you may use BootDreams (on Windows) or similar tools. If you are on non-Windows systems, you may check the img4dc source code.

Using dcload/dc-tool (part of KallistiOS)

If you have a Coders Cable or a Broadband Adapter (BBA) / LAN Adapter, you could also the dcload program (part of KallistiOS) to load it directly on the Sega Dreamcast. It should load as a normal Sega Dreamcast program.

To do that, you may enter the following:

make run

This will execute dc-tool using the mrbtris.elf binary file as target.