TBoI Flash Mods

A mod installer for the original Flash game (The Binding of Isaac, including Wrath of the Lamb/Eternal DLC). Tick the mods you want, click Install, and play.

Mod	What it does	Repository
External Item Descriptions	Descriptions for items, trinkets, cards and pills (F2)	FlashTBoI-EID
Stats HUD	Your current stats on the left side of the screen (F3)	FlashTBoI-StatsHUD
Debug Console	Repentance's debug console: ; opens it (giveitem, spawn, goto, stage, debug, ...)	FlashTBoI-DebugConsole

Usage

1. Download TBoI_Flash_Mods.exe from the latest release, put it where you want to keep the modded game, and start it. (Or with Python 3.8+: python tboi_flash_mods.py, no extra packages.)
2. Check the game folder (found automatically for Steam), tick the mods, click Install / update selected mods. The first time, a game window appears for a few seconds while the game is read.
3. Paste the launch option into Steam (it is copied to your clipboard): right-click The Binding of Isaac > Properties > General > Launch Options. Steam's Play button then starts the modded game. Or click Play.

To change the mods or update them, open the installer again, change the ticks and click Install again. To play the normal game, clear the Steam launch option.

No game files are distributed. Everything is built from your own copy of the game, and the installation in Steam's folder is never changed. The modded game uses the same save as the Steam version: don't run both at the same time. Steam achievements you unlock are sent to Steam by the launcher a few seconds later (Steam must be running).

How it works

For each selected mod, the installer asks GitHub for the mod's latest release, downloads its release zip (EID_Flash_<version>.zip, Stats_HUD_<version>.zip, Debug_Console_<version>.zip) and reads only the payload in it (*_payload.json: the mod's compiled ActionScript, its graphics and the game versions it was tested with). The mod's own patcher script in the zip is never run.

The game SWF is read from a temporary copy of the game (the same method as the mods' own patchers) and kept in cache/, so changing the selection later doesn't start the game again. The payloads are inserted into frame 1 of the SWF, in a fixed order (EID, Stats HUD, Debug Console), and the result is written as:

File
TBoI Flash Mods/isaac_mods.swf	The game with the selected mods
TBoI Flash Mods/flashplayer_32_sa.exe	Adobe's Flash Player 32 projector (downloaded from Adobe, checksum checked)
TBoI Flash Mods/TBoI Flash Mods.exe	Launcher, also the Steam launch option (launcher/FlashModsLauncher.cs)
TBoI Flash Mods/mods.json	Installed mods and versions, and the game folder

Adding a mod

Add it to flashmods/mods.py (GitHub repository, release zip prefix, the name of the atlas it exports). Its release zip must contain a payload in the same format as EID Flash and Stats HUD (doaction, bitmaps, game_sha256).

Development

python tboi_flash_mods.py --source <folder with release zips>   # use local release zips instead of GitHub
python tboi_flash_mods.py --install stats --no-projector        # install without the window
python tools/build_exe.py                                       # -> build/dist/TBoI_Flash_Mods.exe (pip install pyinstaller)

Path	Purpose
tboi_flash_mods.py	Entry point (window, or --install without it).
flashmods/gui.py	Tkinter window.
flashmods/mods.py	The mods and their order.
flashmods/releases.py	Latest release lookup and download (GitHub API, or --source).
flashmods/game.py	Finds the game and reads its SWF from a temporary copy; caches it.
flashmods/swf.py	Inserts payloads into the SWF.
flashmods/install.py	The install steps: payloads, game SWF, projector, launcher, mods.json.
launcher/FlashModsLauncher.cs	TBoI Flash Mods.exe; compiled with Windows' .NET Framework csc (bundled in the exe build, compiled on the player's PC otherwise).

Credits

• External Item Descriptions by Wofsauge and contributors; Flash port and Stats HUD use EID's font and icons.
• The Binding of Isaac © Edmund McMillen & Florian Himsl. No game code or assets are included here.