Tetroid DX

Tetroid DX 1.0

Tetris DX (Game Boy Color) on Android, built by statically recompiling the game with GB Recompiled, not by emulating it. The whole build runs in GitHub Actions; no PC needed.

This repository contains no game data. You supply your own legally obtained ROM, and the app asks for it on first launch, so the APK never contains any part of the game.

Features

Everything is optional and off by default. With every patch off, the game runs its original code.

• Hard Drop and Ghost Piece (light or dark)
• Hold (touch button, or L1 / R1)
• Next-piece previews: five layouts, plus In game for 4:3 handhelds
• Lock Delay
• SRS Rotation
• Randomizer: Tetris DX, 7-Bag or 35-Bag
• Skip Celebrations: Off, Always, or Start skips
• Korobeiniki: Original, or Plus (adds a first panic song)
• Don't Panic
• Palettes: Original, GBC LCD, Swamp, Guideline, Sega, Amber Night
• Scanlines and Mute

Screenshots

On a 4:3 handheld (Retroid Pocket Classic):

Controls

• Touch: on-screen buttons, with quick buttons on top (Mute, Palette, Scanlines, Menu).
• Controller: the touch game buttons hide; D-pad or left stick moves in the menu, A changes, B or Back closes. R3 or Mode opens the menu. L2 changes the palette.
• With All files access (asked once, Android 11+), the save and settings live in a TetroidDX folder in your device's main storage.

How the toggles work

The gameplay changes are small Game Boy assembly patches applied at build time. Instead of changing the game permanently, each patch jumps to a short routine that checks one bit of an options byte in unused ROM space and then runs either the original code or the modified code. The app sets that byte from its menu every frame, so toggles take effect immediately. See android/*.asm.

Building it yourself

You need the ROM Tetris DX (World) (SGB Enhanced).gbc (No-Intro, CRC32 69989152). Never commit a ROM to a public repository.

1. Make a private copy of this repository. Forks of a public repository stay public, so use GitHub's Import repository (or copy the files) into a new private repository instead.
2. Provide the ROM in one of two ways:
   • put the .gbc file in the root of your private copy, or
   • store a direct download link to it in a repository secret named TDX_ROM_URL.
3. Optional but recommended, so updates install over each other: add your own signing key as secrets: TDX_KEYSTORE_BASE64 (the keystore file, base64), TDX_STORE_PASS, and optionally TDX_KEY_PASS and TDX_KEY_ALIAS (default tetrisdx). Without them, each build gets a throwaway key.
4. Actions → Build Tetroid DX APK → Run workflow, then download the TetroidDX-apk artifact.
5. Install it and pick your ROM when the app asks. It is checked against the ROM the build was made from.

Repository layout

• .github/workflows/android.yml: the whole build (ROM checks, patching, recompiling, Android build, a final check that the APK holds no ROM data).
• android/patch_project.py: every change to the generated project, each one asserting it matched exactly, so upstream changes fail loudly.
• android/tdx_menu.inc: the app/game bridge and the pause menu loop.
• android/tdx_platform.inc: native additions (ROM loader, options byte, palettes, scanlines, Hold and preview queue, touch-overlay bridge).
• android/*.java: ROM picker, game activity and touch controls.
• android/*.asm, android/prepare_dontpanic.py: the toggle patches.

Credits

See CREDITS.md. Hard drop and ghost piece by lightbulb-sun (MIT), Don't Panic by DevEd, Skip Celebrations by llakssz, Korobeiniki (Music Fix) by Marc Robledo, Hold / Preview / Lock Delay idea, testing and the Guideline and Sega palettes by CreeperCraftYT, and GB Recompiled by arcanite24 (MIT), plus SDL2, Dear ImGui and RGBDS.

Tetris DX is a trademark of its respective owners. This is an unofficial fan project, not affiliated with or endorsed by Nintendo or The Tetris Company.