Shin Megami Tensei IV for PC (smt4-recomp)

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A native Windows build of Shin Megami Tensei IV (3DS, USA), made by static recompilation: 3dsrecomp translates the game's ARM code into C ahead of time, and that C is compiled into a program of its own, with Zakuro as the runtime for everything else (kernel, services, GPU, sound). The game's code runs natively, not through an emulator's interpreter or JIT.

On top of that, this project adds widescreen, multipliers for Macca, EXP and App Points, frame rate options and cheats, all switched from the in-game cheat menu.

Beta. Played from a new game for more than 10 hours with no crash. The rest of the game hasn't been played on it yet: please report what you find in Issues.

No game files or game code are included, and there is no download. You build it yourself from your own dump of the game. What the build makes (code/ and the program) holds the game's code: don't share it. This project is not affiliated with Atlus, SEGA or Nintendo.

• Features
• Requirements
• Building
• Playing
• Cheats and enhancements
• Controls
• Extracting assets
• Troubleshooting
• How it works
• Credits
• License

• Native code: the game's ARM code recompiled to C and compiled for the PC (95% of it found ahead of time; anything left runs in Zakuro's interpreter).
• Widescreen 16:9 and 21:9: the game draws a wider 3D scene (more view at the sides, same height), not a stretched picture.
• Multipliers x2, x3 and x5 for Macca, hero EXP, demon EXP and App Points, each picked from the cheat menu while playing.
• Easy Recruit: demon negotiations always go your way, from the cheat menu.
• Alignment shown: the hidden Law/Chaos alignment in a corner, and a notice each time a choice changes it.
• 60 FPS (the game runs twice as fast with it) and 30 FPS to go back.
• Community cheats: max Macca, App Points, items, hero EXP, HP/MP and stats.
• Everything Zakuro has: Vulkan or OpenGL, screen layouts, scaling and filters, save states, controllers, 3D.

• Windows 10 or 11, 64-bit. Linux should work too, but hasn't been tried.
• A graphics card with Vulkan (or OpenGL 3.3).
• Your own decrypted dump of Shin Megami Tensei IV (USA), title ID 00040000000E5C00, as .3ds or .cci.
• About 10 GB of free disk space and 8 GB of RAM for the build.
• To build:
  • Rust with the GNU toolchain: rustup default stable-x86_64-pc-windows-gnu
  • MinGW-w64 GCC, 64-bit: winget install BrechtSanders.WinLibs.POSIX.UCRT
  • git

launcher/ is a small program that does it all from a window: choose the folder with your game (it finds the ROM in it), see which tools are missing and install them with winget, download or update this project, build the game with a progress bar, and play.

cd launcher
cargo build --release
target\release\smt4-launcher.exe

It holds no game code, so it can be shared.

git clone https://github.com/Invictus-potens/smt4-recomp
cd smt4-recomp
cargo build-game "C:\path\to\Shin Megami Tensei IV (USA).3ds"

cargo build-game (the builder in tools/build) checks your tools and ROM, fetches and builds 3dsrecomp at the version this project was tested with, recompiles the game's code with this project's changes, builds the program and copies the cheats to Zakuro's cheats folder (adding the missing ones to a cheats file already there, without touching the rest). The recompilation takes 20 minutes or more; add --low-priority to keep using the PC meanwhile. Running it again later only redoes what changed. cargo build-game --help lists the options.

When it's done, the program is target\release\smt4.exe.

The launcher is a Windows program: under Wine it can't install the tools (there's no winget) and the game can't be built there, so it says so and points here. Build on Linux itself instead:

sudo apt install git build-essential   # or your distribution's equivalent
curl https://sh.rustup.rs -sSf | sh    # Rust
git clone https://github.com/Invictus-potens/smt4-recomp
cd smt4-recomp
cargo build-game "/path/to/Shin Megami Tensei IV (USA).3ds"
./target/release/smt4 "/path/to/Shin Megami Tensei IV (USA).3ds"

A player has built and played it this way on Linux (#6); please report any trouble. Another way that's known to work: build on a Windows PC and copy the project folder over; the Windows build runs fine under Wine.

target\release\smt4.exe "C:\path\to\Shin Megami Tensei IV (USA).3ds"

It reads the game's files and everything but the code from your dump, so keep the ROM where it is. Saves, save states and settings go in Zakuro's folder, %APPDATA%\zakuro.

Recommended setup (Escape opens the menu):

1. Settings, Layout: Top screen only. F10 switches to the bottom screen and back, for the map and menus.
2. Settings, Top screen shape: 16:9 (or 21:9 on an ultrawide).
3. Cheats: turn on Widescreen 16:9 (the same shape), then go to another area so the game sets its camera again.

Escape, then Cheats. The ones marked smt4-recomp only work in this build; Enhancements are built into Zakuro, at the top of the window; the others are standard Action Replay codes.

Turn on only one of each multiplier. Turning a multiplier or widescreen cheat off goes back to normal on its own.

How they work: MULTIPLIERS.md, WIDESCREEN.md, RECRUIT.md, ALIGNMENT.md.

Keyboard defaults, all changeable in Settings. Controllers work too.

tools/extract pulls the game's files out of your ROM and converts them: textures to PNG, models to plain CGFX (for SPICA, Ohana3DS or Noesis), text to UTF-8, music, sounds and voices to WAV, cutscenes to MP4.

cd tools\extract
cargo build --release
target\release\smt4-extract "C:\path\to\Shin Megami Tensei IV (USA).3ds" C:\smt4-assets

The formats, what's converted and what isn't: ASSETS.md. Like the build, what it writes is the game's: don't share it.

To replace an image of the game with your own (a portrait, an icon, a background), at the same resolution or higher:

cargo fit-texture <assets>\textures\tex\stex\stbustup\st_bu_pc001.png my_picture.png

It fits your picture where the original's character is and installs it as a texture pack; restart the game to see it. Step by step, and what to do when an image doesn't change: MODDING.md. Upscaling the portraits with AI: UPSCALE.md.

• "no 64-bit gcc found": only an old 32-bit MinGW is installed (one that comes first on PATH is skipped on its own). Install MinGW-w64, for example winget install BrechtSanders.WinLibs.POSIX.UCRT, or set CC and AR to the full paths of a 64-bit gcc.exe and ar.exe.
• .drectve ... unrecognized warnings, then a link error: the gcc that comes with Strawberry Perl has a linker too old for current Rust. The build skips it on its own when another 64-bit gcc is installed; install one with winget install BrechtSanders.WinLibs.POSIX.UCRT.
• linking with `x86_64-w64-mingw32-gcc` failed while compiling smt4-build: Rust links the builder itself with the first x86_64-w64-mingw32-gcc on PATH, before the builder can pick a better one, and that's usually Strawberry Perl's or an old MinGW. Install WinLibs as above and either move its bin folder above the old one in PATH, or set CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER to the full path of its gcc.exe before cargo build-game. The launcher does this on its own.
• "Rust uses the MSVC toolchain", or errors about link.exe: run rustup default stable-x86_64-pc-windows-gnu.
• "is title ..., this project is for Shin Megami Tensei IV (USA)": only the USA release is supported; the code differs between regions.
• The game runs twice as fast: 60 FPS was on at some point. Turn on 30 FPS (Enhancements), then save a state again.
• The picture is squeezed or stretched: the Widescreen cheat and the Top screen shape setting have to match, or both be off.

This is static recompilation, not a decompilation: there is no readable source code of the game here or anywhere in the build. Set SMT4_HOOK_LOG to a file path to have every multiplied gain written to it.

More: progress and known issues, enhancements and roadmap.

• fearkov: 3dsrecomp and Zakuro, which do the heavy lifting.
• lucky: the 60 FPS and 30 FPS codes, from Reshiban/60FPS-AR-CHEATS-3DS.
• JourneyOver and the codes' original authors: the community cheats, from JourneyOver/CTRPF-AR-CHEAT-CODES.
• Shin Megami Tensei IV is by Atlus.

MIT, for the files in this repository only. It doesn't cover the game or anything built from it.