MatrixCode for XScreenSaver

MatrixCode is a standalone OpenGL/GLX XScreenSaver hack designed to reproduce
the flat, sparse, irregular digital code rain associated with the original
Matrix films while remaining light enough for old or low-power X11 systems.

This repository builds one Debian/Ubuntu binary package:

• xscreensaver-screensaver-matrixcode

It installs beside XScreenSaver rather than modifying the upstream
xscreensaver package.

What makes this implementation different

• The glyph grid is stationary; illumination waves travel down it.
• Each active column has one or occasionally two independently paced pulses.
• Trails vary in length, brightness, spacing, and speed.
• Heads approach pale green-white instead of uniform neon green.
• Glyphs mutate selectively as a head passes, with quieter background cycling.
• A custom 8x12 atlas combines original katakana-inspired forms, mirrored
  variants, digits, and punctuation.
• Glow is a lightweight additive texture pass, not a 3D scene or shader stack.
• The renderer has no per-frame heap allocation and defaults to 30 FPS.

The glyph artwork is a clean-room visual interpretation. It does not copy
Warner Bros. film frames, the official Matrix font, official Flash assets, or
third-party glyph textures.

Build

On Debian or Ubuntu:

sudo apt install build-essential pkgconf libx11-dev libgl-dev \
  xvfb xauth libgl1-mesa-dri python3
make
make check

Run a preview:

./matrixcode -window

Render a deterministic test frame:

LIBGL_ALWAYS_SOFTWARE=1 xvfb-run -a \
  ./matrixcode -window -geometry 1280x720 -frames 70 \
  -seed 19990331 -no-vsync -screenshot preview.ppm

Install from source

sudo make install PREFIX=/usr

Installed files:

/usr/libexec/xscreensaver/matrixcode
/usr/share/xscreensaver/config/matrixcode.xml
/usr/share/applications/screensavers/matrixcode.desktop
/usr/share/man/man6/matrixcode.6x

Restart xscreensaver-settings after installation. MatrixCode should appear in
the list of screen savers. It can also be tested directly:

/usr/libexec/xscreensaver/matrixcode -root

Debian/Ubuntu package

sudo apt build-dep .
dpkg-buildpackage -us -uc -b
sudo apt install ../xscreensaver-screensaver-matrixcode_*.deb

The source package is xscreensaver-matrixcode; the installable binary package
is xscreensaver-screensaver-matrixcode.

Useful tuning

The defaults intentionally avoid the common overly dense, overly fast look.
For older hardware:

./matrixcode -window -fps 20 -cell-size 22 -density 34 -glow 48

For a denser display:

./matrixcode -window -density 55 -trail 22 -cell-size 16

See matrixcode(6x) or ./matrixcode -help for every option.

Compatibility

The normal build uses the system OpenGL and GLX development headers. A tiny
compat/minigl.h declaration set exists solely so source-level CI or recovery
environments with runtime GL libraries but no development headers can still
exercise this OpenGL 1.x code. Debian/Ubuntu packages always build against
libgl-dev.

Documentation

• Design and fidelity
• Research notes
• Performance architecture
• Validation
• Build report
• Contributing

License

MIT/X11. See LICENSE.

Matrix, the Matrix code, and related marks are properties of their respective
owners. This project is unofficial and unaffiliated.