A static recompilation of Resident Evil Outbreak (File #1 + File #2) for modern Windows.
No emulator. No compromises. Just Raccoon City, running natively on your PC — alone or online.
RE Outbreak title screen rendering natively on Windows 11 — no emulator
Fan project. Not affiliated with Capcom, Sony, or obsrv.org. You need legally owned copies of the games.
REO takes the original PS2 binaries of both Resident Evil Outbreak games and translates them — instruction by instruction — into native x86-64 code that runs directly on Windows 11. This is static recompilation, the same technique behind projects like Zelda 64: Recompiled.
| Game | Serial | Functions | Recompiled |
|---|---|---|---|
| RE Outbreak | SLUS-20765 | 3,461 | 3,209 functions → 3,829 C++ files |
| RE Outbreak: File #2 | SLUS-20984 | 3,525 | 3,525 functions → 3,892 C++ files |
Both games share the same engine and build against the same runtime HAL.
The PS2 was a wild machine. The Emotion Engine, two Vector Units, a fixed-function Graphics Synthesizer, a sound chip with its own CPU, and a network stack built for 2003-era Japanese broadband. Every piece of that hardware gets replaced with modern equivalents:
| PS2 Hardware | REO Replacement |
|---|---|
| Emotion Engine (R5900 MIPS) | Static recompilation → native x86-64 |
| Vector Units (VU0/VU1) | SSE/AVX SIMD + custom microcode translator |
| Graphics Synthesizer | Vulkan renderer (via paraLLEl-GS or custom) |
| SPU2 Sound | Software mixer → Windows audio (WASAPI) |
| IOP (I/O Processor) | High-level emulation of IRX modules |
| PS2 Network Adapter | Native Winsock, compatible with obsrv.org |
| DNAS Authentication | Bypassed (servers are long dead) |
| DualShock 2 | XInput / DirectInput / keyboard+mouse |
The original RE Outbreak was one of the first PS2 games with online multiplayer — and it was great. When Capcom shut down the servers, the community at obsrv.org brought them back.
REO connects to those same community servers. Play with friends, matchmake with strangers, survive together — just like 2004, but at 1080p+ and 60fps.
- Connect to obsrv.org — join the existing community
- Self-host — run your own server for LAN parties or private games
- Offline — full single-player with AI partners, no internet required
┌─────────────┐ ┌──────────────┐ ┌───────────────┐ ┌──────────────┐
│ Outbreak │ │ ps2xAnalyzer │ │ ps2xRecomp │ │ REO Runtime │
│ ISO/ELF │────▶│ (analysis) │────▶│ (MIPS→C++) │────▶│ (HAL+game) │
│ SLUS_207.65│ │ TOML config │ │ native code │ │ reo.exe │
└─────────────┘ └──────────────┘ └───────────────┘ └──────────────┘
│
┌────────────────────────┤
▼ ▼
┌─────────┐ ┌────────────┐
│ Vulkan │ │ Network │
│Renderer │ │ Stack │
│ (GS) │ │ (obsrv.org)│
└─────────┘ └────────────┘
- Extract the ELF binary from your legal game disc/ISO (File #1 or File #2)
- Analyze it with ps2xAnalyzer to map functions, relocations, and symbols
- Recompile MIPS R5900 instructions to C++ with ps2xRecomp
- Link against the REO runtime — our replacement for all PS2 hardware
- Play natively on Windows — choose which game with
--game file1or--game file2
The recompiled game code thinks it's talking to PS2 hardware. The REO runtime intercepts every hardware access and translates it:
- Memory — 32MB unified address space with scratchpad, MMIO regions, and TLB support
- Graphics — GS register writes are captured and rendered via Vulkan compute shaders
- Audio — SPU2 ADPCM voices mixed in software, output via WASAPI
- Input — DualShock 2 reads mapped to modern controllers and keyboard
- Network — IOP network module calls translated to native TCP/IP sockets
- Filesystem — CD/DVD reads redirected to extracted game data on disk
- Video — Sofdec/SFD cutscenes decoded via FFmpeg
- Timing — EE/IOP cycle counting replaced with high-resolution Windows timers
reo/
├── CMakeLists.txt # Top-level build
├── README.md # You are here
│
├── game_data/ # Extracted File #1 data (SLUS_207.65 + assets)
├── game_data_file2/ # Extracted File #2 data (SLUS_209.84 + assets)
│
├── tools/ # Build-time and debug tools
│ ├── iso_extract/ # Extract game files from ISO/BIN
│ ├── elf_analyze/ # ELF analysis and symbol extraction
│ ├── vu_disasm/ # VU microcode disassembler
│ ├── gs_dump_replay/ # GS dump replay tool (validates renderer)
│ └── ps2_debug/ # PCSX2 Pine IPC scripts (overlay dump, GS capture)
│
├── recomp/ # Static recompilation layer
│ ├── config/
│ │ ├── outbreak.toml # PS2Recomp config — File #1
│ │ ├── outbreak_file2.toml # PS2Recomp config — File #2
│ │ ├── output/ # 3,830 recompiled C++ files (File #1)
│ │ ├── output_file2/ # 3,892 recompiled C++ files (File #2)
│ │ └── output_overlay/ # 95 runtime overlay functions (0x370000+)
│ ├── overrides/ # Game-specific overrides + hardware bridge
│ └── patches/ # Binary patches and fixups
│
├── runtime/ # Hardware Abstraction Layer
│ ├── core/ # CPU context, memory map, syscalls
│ ├── gs/ # Graphics Synthesizer → Vulkan
│ ├── spu2/ # Sound processing → WASAPI
│ ├── vu/ # Vector Unit microcode execution
│ ├── iop/ # I/O Processor HLE
│ ├── input/ # Controller/keyboard mapping
│ ├── cdvd/ # Disc I/O → file system
│ └── timer/ # Timing and vsync
│
├── network/ # Online play
│ ├── snap_client/ # SN@P protocol implementation
│ ├── dnas/ # DNAS auth bypass
│ ├── lobby/ # Lobby browser and matchmaking
│ └── server/ # Optional local server
│
├── media/ # Media decoders
│ ├── adx/ # CRI ADX audio decoder
│ ├── sofdec/ # CRI Sofdec video decoder
│ └── tim2/ # TIM2 texture converter
│
├── game/ # Game-specific code
│ ├── formats/ # NBD, AMO, RDT, etc. file parsers
│ ├── scripts/ # Game script interpreter
│ └── ui/ # Menu and HUD reimplementation
│
└── third_party/ # External dependencies
├── PS2Recomp/ # Static recompilation toolchain
├── parallel-gs/ # Vulkan GS renderer
├── SDL3/ # Window/input management
└── volk/ # Vulkan loader
Prerequisites: Visual Studio 2022, CMake 3.20+, Vulkan SDK, legally owned RE Outbreak NTSC-U ISO(s)
# Clone
git clone https://github.com/sp00nznet/reo.git
cd reo
# Clone PS2Recomp (recompilation toolchain)
git clone https://github.com/ran-j/PS2Recomp.git third_party/PS2Recomp
# Build PS2Recomp tools
cd third_party/PS2Recomp
cmake -S . -B out/build -G "Visual Studio 17 2022" -A x64
cmake --build out/build --config Release
cd ../..
# Build REO tools
cmake -B build -G "Visual Studio 17 2022" -A x64
cmake --build build --config Release
# ── File #1 (SLUS-20765) ──
./build/tools/iso_extract/Release/reo-extract.exe "Outbreak.iso" game_data
./third_party/PS2Recomp/out/build/ps2xAnalyzer/Release/ps2_analyzer.exe \
game_data/SLUS_207.65 recomp/config/outbreak.toml
./third_party/PS2Recomp/out/build/ps2xRecomp/Release/ps2_recomp.exe \
recomp/config/outbreak.toml
# ── File #2 (SLUS-20984) ──
./build/tools/iso_extract/Release/reo-extract.exe "OutbreakFile2.iso" game_data_file2
./third_party/PS2Recomp/out/build/ps2xAnalyzer/Release/ps2_analyzer.exe \
game_data_file2/SLUS_209.84 recomp/config/outbreak_file2.toml
./third_party/PS2Recomp/out/build/ps2xRecomp/Release/ps2_recomp.exe \
recomp/config/outbreak_file2.toml
# Rebuild with recompiled code
cmake --build build --config Release
# Run (choose game)
./build/recomp/Release/reo_recomp.exe --game file1
./build/recomp/Release/reo_recomp_file2.exe --game file2The recompilation pipeline is working for both games. File #1 boots to its main loop with the full rendering pipeline active, hardware bridge connecting recompiled code to native subsystems, live controller input, and disc I/O infrastructure wired.
| File #1 | File #2 | |
|---|---|---|
| ISO extraction | all files extracted | all files extracted |
| ELF analysis | 3,461 functions | 3,525 functions |
| MIPS → C++ | 3,209 → 3,830 files (66 MB) | 3,525 → 3,892 files (68 MB) |
| Runtime overlays | 95 functions (0x370000+) | pending |
| Build | compiles clean (3,923 files) | compiles clean (3,892 files) |
| Boot | rendering game textures | pending |
File #1 rendering progress:
- ELF loads, entry point executes, main loop runs continuously at 60fps with 6 active tasks
- Textured rendering working — game texture data from NETBIO archives visible on screen through GS software rasterizer
- Full scene render chain executing — 193KB scene renderer (sub_001D3DC0) runs every frame: scene lookup → render target allocation → scene builder → render finalization
- GS software rasterizer — supports flat sprites, textured sprites (PSMCT32 + PSMT8 indexed), GIF IMAGE mode (swizzled VRAM upload), A+D register writes, XYOFFSET, scissor clipping, alpha test (TEST_1), alpha blending, PSMCT32 VRAM swizzle tables
- NETBIO archive reader — parses AFS archives including nested romdata_usa.afs (1,342 game files), loads NBD scene data
- Live controller input — XInput controllers and keyboard wired to game's pad buffer
- SIF RPC bridge — PS2Recomp dispatches to CDVD/PADMAN/MCSERV/LIBSD handlers
- CDVD filesystem — 85 game files mapped from extracted game_data/
- GIF DMA pipeline — display list double-buffering, tag array management, DMA source chain traversal
- 95 runtime overlay functions + 30+ HLE function overrides for boot/rendering chain
- Binary trace logger + PCSX2 Pine IPC debug tools + NETBIO archive tools
Rendering pipeline (15 stages unblocked):
SIF Init → Module Load → Task Wait → Display Flush → Render Dispatch →
TIM2 Bypass → DL Alloc → Task Creation → Buffer Recycle → Scene Lookup →
Render Target → DMA Buffer → Scene DRAW → Scene Builder → GIF→GS ✅
Resolved issues (25+ fixes):
- SIF DMA status check, SifLoadModule HLE, memcpy counter wrap
- IOP task wait bypass, display list flush bypass, render dispatch dual entry
- TIM2 validation bypass, display list HLE allocator, DMA buffer allocator
- Render target allocator chain (128F80→128F28→1303D8)
- Scene builder + render finalization stubs for uninitialized render contexts
- TEX0 register storage bug, VRAM page conflict for texture uploads
- Multiple mid-function entry points registered (0x13F998, 0x37A5A0)
- Per-frame task table + DMA channel + display list write pointer recycling
Debug tools:
reo-gs-replay— replays PCSX2 GS dumps through REO's GS rendererreo-gs-gen-test— generates synthetic GS test dumpsdump_task_table.py— PCSX2 Pine IPC script for capturing game state- Binary trace logger — records DMA/GIF/VU/GS events (
REO_TRACE=1) - NetbioReader — streaming access to NETBIO/AFS archives without full memory load
Milestones:
- 2025-03-13: Proof of life — debug overlay on live GS framebuffer
- 2025-03-19: First rendered pixels — flat colored sprites visible on screen
- 2025-03-19: First textured rendering — game texture data rendered through GIF→GS pipeline
- 2025-03-20: Title screen rendered — RE Outbreak title screen with correct colors displayed natively on Windows, including the eye graphic, "RESIDENT EVIL OUTBREAK" logo, and "PRESS START BUTTON" text
- 2025-03-21: GS dump replay working — PCSX2 GS dumps replayed through REO's software rasterizer with correct output. Title screen and in-game demo scenes render pixel-accurate with PSMCT32 textures, PSMT8 indexed textures, GS VRAM swizzle tables, XYOFFSET coordinate correction, and TEST_1 alpha test support
- 2025-03-28: NBD geometry parsing — reverse-engineered NBD/AMO binary format, rendering 3D game models (rooms + characters) from NETBIO archives with triangle strip support
- 2025-04-07: TEX chunk decompression — reverse-engineered RE Outbreak's custom OB-LZ77 compression, all game textures (256x256 IDX8 with CLUT) decompress and decode correctly
- 2025-04-07: PS2Recomp upstream sync — synced with latest PS2Recomp runtime + applied 5 critical codegen fixes (VU0 dest-mask, divide-by-zero, 64-bit branches) from community contributor jlsandri
- Project structure and build system
- ISO extraction and ELF analysis tooling (working for both games)
- PS2Recomp integration — File #1: 3,461 functions, File #2: 3,525 functions
- Dual-game build system (reo_recomp + reo_recomp_file2)
- Game selection via --game flag and auto-detected data paths
- Basic memory map and CPU context runtime (32MB RAM, MMIO, scratchpad)
- Bridge recompiled code to REO runtime (82+ override bindings)
- Boot to main loop (game update function executing)
- Runtime overlay capture — 95 functions from PCSX2 Pine IPC
- Hardware bridge (DMA/GIF/VU/GS interception layer)
- Un-stub rendering pipeline (13 core functions)
- Debug tooling (GS dump replay, binary trace logger, PCSX2 IPC scripts)
- GIF DMA pipeline flowing (display list → tag commit → DMA chain → GSRenderer)
- Render first frame (proof of life — debug overlay on live GS framebuffer)
- Input system — XInput controllers + keyboard mapped to DualShock 2
- SIF RPC bridge — PS2Recomp dispatches to CDVD/PADMAN/MCSERV/LIBSD handlers
- CDVD filesystem — game files mapped from extracted data
- SIF module loading — SifLoadModule HLE for IOP address loads
- GS software rasterizer — flat sprites, textured sprites, VRAM texture upload
- NETBIO archive reader — parse AFS archives, load NBD game data
- Scene render chain — 15 stages unblocked, full DRAW cycle executing
- First game textures rendered on screen
- Title screen rendered with correct colors
- NBD/AMO geometry parser — reverse-engineered binary format, room + character models
- TEX chunk decompression — OB-LZ77 custom compression, TIM2 texture decoding (IDX8/IDX4/RGBA32)
- GS dump replay — replay PCSX2 GS dumps through REO's renderer (title + demo scenes verified)
- Upload decoded textures to GS VRAM — textured 3D model rendering
- Wire NBD scene data to scene manager — enable game's own rendering
- GS renderer (Vulkan) — upgrade from software rasterizer
- VU microcode translation for geometry
- SPU2 audio mixer — hear the first sound
- Full game boot to main menu
- Sofdec FMV playback
- Save/load system (memory card → local files)
- Single-player gameplay loop
- SN@P network protocol client
- DNAS bypass for obsrv.org connectivity
- Lobby browser and matchmaking
- Online multiplayer gameplay
- Optional local server bundling
- 60fps support (original was 30fps locked)
- Resolution scaling and widescreen
- Modern graphics enhancements
- Keyboard+mouse controls
- Steam Deck / Linux support (stretch goal)
- PS2Recomp — Static recompilation toolchain for PS2
- paraLLEl-GS — Vulkan compute GS renderer
- obsrv.org — Community Outbreak servers
- obsrv-pack — Open source server bundle
- Outbreak Research — File format documentation
- REOF2 — RE Outbreak File #2 decompilation (reference)
- libthanatos — RE Outbreak NBD/TEX parser + OB-LZ77 compression (reference)
- OBTool — RE Outbreak modding tool, TIM2 texture handling (reference)
- ghidra-emotionengine-reloaded — PS2 Ghidra plugin
- PS2Tek — PS2 hardware documentation
- Copetti PS2 Architecture — Architecture deep-dive
This project contains no copyrighted game code or assets. You must provide your own legally obtained copies of Resident Evil Outbreak (SLUS-20765) and/or RE Outbreak: File #2 (SLUS-20984).
Resident Evil is a trademark of Capcom. PlayStation is a trademark of Sony. This is an independent fan project created for preservation and educational purposes.
This is a massive undertaking and help is welcome. If you know PS2 internals, MIPS assembly, Vulkan, or just really love Outbreak — open an issue or PR.
Don't let the memory of Raccoon City die.