Native Java version of the Amiga game Nibby Nibble (© 1993 Gabriele Roncolato). It was rewritten
in plain Java from the knowledge gained by decompiling the original 68000 program
(see the emulated version in the emu/ folder of this repository, which ports the
original code routine by routine on top of a small Amiga chipset emulation).
There is no emulation here: no 68000, no copper, no blitter, no Amiga memory. The graphics, levels and
music were extracted from the original data file into PNG images, text files and a .mod module,
and the game is plain Java code: three layers (maze, sprites, snake body) composed into a 320×262 frame,
a 32-colour palette for the fades and death effects, and a stand-alone module player.
| folder | content |
|---|---|
/ (root) |
native Java version (this README): extracted assets, plain Java game |
emu/ |
emulated Java port: the original 68000 routines translated one by one on top of a small Amiga chipset emulation, the original data file, the disassembly listings and the analysis tools |
tools/ |
asset extractor (extract_assets.py) |
 |
 |
| Title screen | Level 1 |
 |
 |
| Level 2 | Death: the body burns from the tail to the head |
The behaviour was checked against the emulated version (which runs the original logic): with the same inputs, both versions produce pixel-identical frames — title, cheat code, gameplay, eating, growth, self-bite, time-out death, burning/spinning/explosion animations, end-of-level fades, level skip, return to the title — and the same audio (within ±1 rounding unit of the 16-bit mix).
Details reproduced from the original code include: 2-pixel steps per frame, turns only on a tile, walls that stop the snake, growth every 2 then 1 dots (91 segments max), the snake body drawn one frame late (triple buffering in the original), the pixel-accurate head/body collision (only body pixels of colour 3 count), the timer that only kills when moving at 0, the copper rainbows, the status bar refreshed by the music routine, and the sound effects that temporarily replace channel 2 of the music.
This project exists only for the preservation of Amiga video game heritage and for educational
use. The original game, © 1993 Gabriele Roncolato, was distributed as public domain software on
the cover disk of the French magazine Amiga Dream; all credit for the game goes to its author.
The assets in src/main/resources/assets/ were extracted unmodified from the original game data; they
are not covered by the MIT license. This project is strictly non-commercial; if a rights holder wishes
it to be taken down, just open an issue or contact the author.
Author of the Java version: Guillaume Monet (guillaume.monet@free.fr). License: MIT for the code, tools and documentation.
Requirement: JDK 21. Nothing else: the assets are bundled in the jar.
gradle run
# or
gradle jar
java -jar build/libs/nibbynibble.jarPortable Windows build with an embedded runtime: gradle jpackageImage (output in
build/dist/NibbyNibble, run NibbyNibble.exe).
Options: --scale N (window zoom, default 3), --lives / --time (unlimited lives / time trainers),
--headless FRAMES DIR events... (runs without a window, saves PNG frames and audio.wav; events are
frame:action with fire|up|down|left|right|lmb|rmb|esc followed by +/-, key=X+/key=X-
(_ for space) or shot).
| Action | Keys |
|---|---|
| move | arrow keys (or numpad 8/2/4/6) |
| fire (start) | Shift, Ctrl or Enter |
| back to title | Esc |
| quit | F10 or close the window |
| skip level (original cheat) | right click + fire + left click |
Original cheat: type THE RONCLER GANG on the title screen → infinite lives (and the timer stops).
nibby/Main.java window, keyboard/mouse, 50 Hz loop paced by the audio line, headless mode
nibby/Game.java the game: title, levels, movement, growth, collisions, fades, death, rendering
nibby/ModPlayer.java 4-channel module player (the game's NoiseTracker-style replay) + sound effects
nibby/Level.java a maze loaded from levels/levelNN.txt + its two tiles
nibby/Bitmap.java image of palette indices (cookie-cut drawing, erasing)
nibby/Assets.java loading of the indexed PNG files and text files
nibby/Input.java input state
tools/extract_assets.py rebuilds src/main/resources/assets/ from the original data file
(Python 3 + Pillow):
python tools/extract_assets.py emu/original-assets/Nibby src/main/resources/assets| file | content |
|---|---|
title.png, statusbar.png, stage.png, gameover.png, digits.png |
screens, status bar, banners, 8×8 digits |
rainbow.txt |
the copper rainbow colour table |
levels/levelNN.txt |
dot count, time, palette and 20×14 map (0 wall, . dot) |
levels/levelNN_wall.png, levelNN_dot.png |
the 16×16 tiles of each level |
sprites/head_*, tail*, signature.png |
head (attached sprites, 4 directions × 3 frames), tail pieces, "GR" signature |
shapes/body_*, burn_*, explosion_* |
body shapes and mask, burning and explosion frames |
nib-rsi.mod |
the music (ProTracker module, sample 16 "esplosione" and 17 "bopp" are the sound effects) |
Images are indexed PNG files: the game uses the palette indices and applies its own palettes at run time.