XBoing
XBoing is a fast, colorful breakout arcade game. Bounce a proton ball
off your paddle to smash every block on the screen, then do it again
across 80 levels of bombs, teleports, sticky paddles, and power-ups.
Juggle up to five balls at once, chase the high score, and design your
own levels in the built-in editor.
A faithful SDL2 port of Justin C. Kibell's X11 original, XBoing 2.4
(released 1996). Current release: 1.0.12.
Home page, screenshots, and downloads (including the original 1996 release): techrescue.org/xboing.
Install
XBoing installs with Homebrew on macOS and Linux:
brew install jmf-pobox/xboing/xboing
On macOS Apple Silicon and Linux (x86_64 or aarch64), this pours a
prebuilt bottle — no compiler needed. Every other platform (e.g.
macOS Intel) falls back to Homebrew's normal source build
automatically.
Prefer a Debian package or a source build? See Building.
How to play
Run xboing. Clear every block on a level without letting the ball fall past your paddle.
- Move the paddle — move the mouse, or the arrow keys
- Launch the ball —
Space, or click a mouse button
- Fire bullets —
K, or click a mouse button
- Pause / tilt / quit —
p / t / q
The full key map, the level editor, scoring, and every command-line option are in the manual:
man xboing
History
Justin C. Kibell wrote the original XBoing on a SparcStation 2 to learn Xlib. Version 2.4 was released on 22 November 1996 and distributed via ftp.x.org/contrib/games. The game uses pure Xlib — no Motif, no Xt — with the XPM library for pixmap graphics, and was published under an X Consortium-style permissive license.
The 1996 sources are preserved verbatim in original/, including Kibell's original README and copyright notice.
Acknowledgements
- Justin C. Kibell — original game design, code, and artwork (1993–1997).
- Arnaud Le Hors — the XPM library that made Kibell's pixmap-driven graphics possible.
- Anthony Thyssen — background imagery.
- All the contributors who sent Kibell bug reports, patches, and platform fixes during the original game's lifetime. See
original/README for the full credits.
Modernization
This is an incremental modernization, not a rewrite. The 1996 Xlib sources stay in original/ as the canonical reference; the new SDL2 implementation lives in src/ and include/. Game behavior — level format, scoring values, physics constants, paddle bounce trigonometry — is preserved. All 80 original levels load and play unchanged.
| Subsystem | Original (1996) | Modernized |
|---|
| Windowing | Xlib + private colormap + GCs | SDL2 |
| Graphics | XPM via libXpm | PNG via SDL2_image |
| Audio | fork() + /dev/dsp + 12 platform drivers | SDL2_mixer |
| Sound format | .au (Sun audio) | OGG / WAV |
| Build | hand-written Makefile + Imake | CMake |
| Paths | compile-time #defines | XDG Base Directory spec |
| Fonts | XLFD bitmap fonts | bundled TTF via SDL2_ttf |
Status: release 1.0.12. All six phases of the integration roadmap are done; remaining work is tracked in beads.
For deeper detail:
Building
Development build:
sudo apt install build-essential cmake pkg-config libsdl2-dev \
libsdl2-image-dev libsdl2-mixer-dev libsdl2-ttf-dev libcmocka-dev
cmake --preset debug
cmake --build build
ctest --test-dir build --output-on-failure
./build/xboing
The presets need CMake 3.21 or newer; on older CMake, configure with cmake -B build -DCMAKE_BUILD_TYPE=Debug instead.
Sanitizer build — the primary safety net during modernization of a 1990s-era C codebase:
cmake --preset asan
cmake --build build-asan
ctest --test-dir build-asan --output-on-failure
The Makefile wraps these: make build, make test, and make check (all CI gates). Run make help for the full target list.
Debian package
On Debian or Ubuntu, build and install a native .deb:
sudo apt install build-essential devscripts debhelper cmake pkg-config \
libsdl2-dev libsdl2-image-dev libsdl2-mixer-dev libsdl2-ttf-dev libcmocka-dev
dpkg-buildpackage -us -uc -b
sudo dpkg -i ../xboing_*.deb
The package installs setgid games, which enables a shared, system-wide high-score table under /var/games/xboing (see ADR-047) — something the Homebrew build does not provide.
Source layout
| Directory | Contents |
|---|
src/, include/ | Modernized SDL2 implementation: 38 static libraries plus integration glue |
tests/ | CMocka unit, integration, fuzz, and replay tests |
levels/ | 80 level data files, unchanged from 1996 |
sounds/, assets/ | Audio assets, fonts, and converted PNG sprites |
original/ | 1996 Xlib sources, preserved as reference |
docs/ | Specification, modernization plan, design decisions |
debian/, packaging/ | Debian packaging, .desktop file, AppStream metainfo, icons |
Read CLAUDE.md for development principles, quality gates, and commit conventions; AGENTS.md covers the bd issue-tracking workflow.
License
- Modernization (everything outside
original/): MIT, © 2025–2026 J Freeman (jmf-pobox).
- Original 1993–1997 sources (
original/): X Consortium-style permissive license, © Justin C. Kibell. Preserved verbatim in original/COPYRIGHT.
