# Project Sylpheed: Arc of Deception — Reborn

A clean-room, open-source reimplementation of **Project Sylpheed: Arc of Deception** (Xbox 360, 2006).

Built with **Rust** and the **Bevy** game engine. Runs natively on Windows, macOS, and Linux, and in the browser via WebAssembly.

> **Legal note:** This project contains no original game code or assets. You must own a legitimate copy of Project Sylpheed to use this engine. Assets remain the intellectual property of SETA Corporation / Square Enix.

---

## Current Status: Milestone 1 — Asset Explorer

- [x] XISO disc image reading via `xdvdfs`
- [x] Xbox 360 texture de-tiling (Morton / Z-order)
- [x] XPR2 texture container parsing
- [x] Bevy custom `AssetLoader` for `.xpr` textures
- [x] Orbit camera viewer
- [x] CLI tools: extract, list, sniff, texture info, texture export
- [x] GitHub Actions CI (Windows + macOS + Linux + WASM)
- [x] WASM / web build target
- [ ] Mesh format (reverse engineering in progress)
- [ ] Audio format (XMA → PCM pipeline)
- [ ] Mission data format

---

## Repository Structure

```
sylpheed-reborn/
└── sylpheed-viewer/        ← Milestone 1: asset explorer (Rust/Bevy workspace)
    ├── Cargo.toml          ← Workspace root
    ├── crates/
    │   ├── sylpheed-formats/   # Format parsers — no Bevy dependency
    │   │   ├── xiso.rs         # XISO / XDVDFS disc image reader
    │   │   ├── texture.rs      # XPR2 container + DXT de-tiling (Morton)
    │   │   ├── vfs.rs          # Virtual filesystem + magic-byte sniffer
    │   │   ├── mesh.rs         # Mesh parser (stub — RE in progress)
    │   │   └── audio.rs        # Audio parser (stub — XMA TODO)
    │   │
    │   ├── sylpheed-viewer/    # Bevy application
    │   │   ├── lib.rs          # App setup + WASM entry point
    │   │   ├── main.rs         # Native binary entry point
    │   │   ├── asset_loader.rs # Custom Bevy AssetLoaders
    │   │   ├── camera.rs       # Orbit camera (LMB orbit, RMB pan, scroll zoom)
    │   │   └── ui.rs           # egui file browser + RE notes panel
    │   │
    │   └── sylpheed-cli/       # Command-line tools
    │       └── main.rs         # extract / list / sniff / texture info commands
    │
    ├── assets/             ← Extracted game files (gitignored)
    ├── .github/workflows/
    │   └── ci.yml          # CI: Windows + macOS + Linux + WASM
    ├── Trunk.toml          # WASM build configuration
    └── justfile            # All build recipes
```

---

## Getting Started

### Prerequisites

```bash
# Install Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# Install just (task runner)
cargo install just

# For web builds only
cargo install trunk
rustup target add wasm32-unknown-unknown
```

#### Linux — Bevy system dependencies

```bash
sudo apt-get install -y \
  libasound2-dev libudev-dev libwayland-dev \
  libxkbcommon-dev libx11-dev libxi-dev pkg-config
```

### Step 1 — Extract your disc

```bash
cd sylpheed-viewer

# Extract using the CLI tool
just extract /path/to/project_sylpheed.iso

# Or manually with xdvdfs
cargo install xdvdfs-cli
xdvdfs unpack project_sylpheed.iso ./assets/
```

### Step 2 — Run the viewer

```bash
cd sylpheed-viewer

just run          # Native viewer
just web          # WASM dev server → http://localhost:8080
```

The asset viewer opens an orbit camera scene. Use the left panel to browse extracted game files. Click a `.xpr` file to preview it as a texture.

---

## Build Commands

All commands run from the `sylpheed-viewer/` directory.

```bash
just run              # Run the native viewer (debug)
just run-dev          # Run with hot-reloading
just build-native     # Build native release binary
just web              # WASM dev server at localhost:8080
just build-web        # WASM release build → ./dist/

just extract game.iso # Extract an ISO to ./assets/
just sniff            # Identify file formats in ./assets/
just sniff-unknown    # Show only unrecognised formats (RE focus)

just test             # Run all tests
just ci               # Full CI: fmt + lint + test + WASM check
```

---

## Technology Stack

| Layer | Choice | Reason |
|-------|--------|--------|
| Language | **Rust** | Memory safety, performance, cross-platform |
| Game engine | **Bevy 0.15** | ECS-first, WASM-native, data-driven |
| XISO reading | **xdvdfs** | Pure Rust, reads Xbox 360 disc images |
| Binary parsing | **binrw** | Derive-macro based, ideal for RE work |
| Web bundler | **Trunk** | Bevy's standard WASM build tool |
| CLI | **clap** | Asset extraction and inspection tools |
| Debug UI | **bevy_egui** | In-viewer asset browser and RE notes panel |

---

## Key Architectural Decisions

**`sylpheed-formats` has zero Bevy dependency.** All binary format parsers live here and are testable with plain `cargo test`. Bevy integration is a thin layer on top in `sylpheed-viewer`.

**WASM is a first-class target.** XISO reading is gated behind `#[cfg(not(target_arch = "wasm32"))]` since the browser can't read local files. On the web, assets must be pre-extracted and served over HTTP.

**Modding is designed in from the start.** The virtual filesystem (`vfs.rs`) is the single choke point for all asset reads — a mod loader only needs to intercept that one layer to override any file.

---

## Reverse Engineering Notes

### Known file formats

| Path pattern | Format | Status | Notes |
|---|---|---|---|
| `*.XPR`, `*.XPR2` | XPR2 texture | ✅ Parsing | DXT1/3/5, DXN, Morton de-tiling done |
| `DEFAULT.XEX` | Xbox EXE 2 | 🔬 Study | Main executable — load in Ghidra (PPC BE) |
| `*.XWB`, `*.XSB` | XACT audio | ⏳ TODO | Wave/sound banks; audio is XMA codec |
| `*.pak`, `*.p00` | SETA archive | ⏳ Unknown | Paired header/data format |
| mesh files | Unknown | ⏳ TODO | Run `just sniff-unknown` to find candidates |

### RE workflow

```bash
# 1. Extract and map the disc
just extract game.iso
just sniff-unknown   # shows hex magic bytes of unknown files

# 2. Hex-inspect candidates
#    Groups of 12 bytes at offsets: likely f32 XYZ vertices
#    Groups of 6 bytes:             likely u16 triangle indices

# 3. Cross-reference in Ghidra
#    Load DEFAULT.XEX with PowerPC Big-Endian processor
#    Search string refs to file extensions → find load functions

# 4. Implement parser
#    Add binrw #[derive(BinRead)] struct in sylpheed-formats/src/mesh.rs
#    cargo test -p sylpheed-formats
```

### Next steps (Milestone 2)

1. **Mesh format** — fingerprint with `sniff-unknown`, implement `mesh.rs`
2. **Audio** — parse XWB headers, batch-convert XMA to WAV via `ffmpeg`
3. **Mission data** — format unknown; starts after mesh/texture loading works
4. **Flight model** — document by playing the original; implement as Bevy system

---

## Constraints

1. **Never copy decompiled or disassembled game code** — reimplement behavior through observation only.
2. **Assets stay gitignored** — `assets/` and `*.iso` are excluded. Never commit game files.
3. **Keep `sylpheed-formats` Bevy-free** — parsers must be testable without a GPU.
4. **WASM must always compile** — CI enforces `cargo check --target wasm32-unknown-unknown`.
5. **`justfile` is the source of truth** for build commands — add new recipes there.

---

## Milestone Roadmap

| Milestone | Goal | Status |
|---|---|---|
| 1 | Asset Explorer | 🚧 In Progress |
| 2 | Flying Tech Demo | ⏳ Planned |
| 3 | Combat Prototype | ⏳ Planned |
| 4 | Mission 1 Playable | ⏳ Planned |
| 5 | Full Game (all 16 missions) | ⏳ Planned |
| 6 | Mod SDK | ⏳ Planned |

---

## Useful References

- [xdvdfs](https://github.com/antangelo/xdvdfs) — XISO disc image reader (used in this project)
- [Xenia emulator](https://github.com/xenia-canary/xenia-canary) — GPU/API reference (cloned at `../../xenia-canary/`)
- [xboxdevwiki](https://xboxdevwiki.net) — Xbox 360 hardware documentation
- [binrw docs](https://binrw.rs) — binary format parsing framework
- [Free60 Project](https://free60project.github.io/wiki/) — open Xbox 360 hardware docs