Puddz / AstralChain-PC

# Astral Chain PC
> [!IMPORTANT]
> **This project was built entirely with AI.** All of the code, tooling, reverse engineering and
> documentation in this repository was written by an AI model (Anthropic's Claude, through Claude Code, and Codex), directed,
> tested and reviewed by the project's owner. It is shared as is, as a fan project. If you prefer not to use
> AI-written code, you are free to skip it. As with any code from the internet, you build and run it at your own
> discretion.
An unofficial, experimental native Windows port of *Astral Chain* (Nintendo Switch, PlatinumGames, 2019), made by
**static recompilation**. The game's ARM64 code is translated to C and compiled into an ordinary Windows x64
program, and its NVN graphics calls run on Vulkan. There is no emulator or JIT.
You build it yourself from **your own** legally dumped game and keys. This repository contains no game code, assets,
shaders, keys or firmware, and never will. Everything the setup produces comes from your dump: do not share the
`build/`, `game/` or `userdata/` folders.
> **AI disclosure.** Most of the code, tooling, reverse engineering and documentation here was written by Claude
> (Anthropic) through Claude Code, directed and tested by the repository owner. It is shared as-is as a fan project.
## Status
| | |
| --- | --- |
| Tested | Title, menus, opening cutscene, character creation, the highway chase and the first on-foot section of File 01 |
| Frame rate | 60 fps target, cutscenes included (Dynamic-FPS patch, game speed correct at any frame rate). RTX 4090 / Ryzen 7 7800X3D: 57-60 fps. `AC_CUTSCENE_FPS=30` plays cutscenes exactly as the original does |
| Stability | Driver watchdog plus a GPU hang stop. No driver resets since 2026-10-19 across dozens of test runs |
| Saving | Works (tested in File 01) |
| Not yet tested | Everything after the first on-foot section of File 01 |
Known issues are listed under Known issues.
## Requirements
- Windows 10 or 11, 64-bit.
- A GPU with Vulkan 1.3. Developed on an NVIDIA RTX 4090; other GPUs are untested.
- Python 3.12 or newer, with the `py` launcher (the installer default).
- About **35 GB** free during setup. About 11 GB stays afterwards.
- An internet connection for the one-time setup. It downloads Zig, glslang and NSTool at pinned versions,
 checked by SHA-256.
- Your own dump:
 - the **base game** (title ID `01007300020FA000`), as an XCI or an NSP;
 - the **v1.0.1 update** NSP. Exactly v1.0.1 is required;
 - your console's **`prod.keys`**.
How to dump games and keys from your Switch is not covered here.
## Setup
1. Download this repository: **Code → Download ZIP**, or `git clone`. Put it in a folder you own, for example
 `C:\Games\AstralChain-PC`. The path should be short, and not on a network drive.
2. Double-click **`setup.cmd`** and pick, when asked:
 1. your `prod.keys`;
 2. the base game (XCI or NSP);
 3. the v1.0.1 update NSP.
3. Wait. Setup extracts the game data, packs it into `game\romfs.bin`, then translate