OpenSkyrim

An open-source engine reimplementation for The Elder Scrolls V: Skyrim (Special Edition) built in Rust using the Bevy Engine.

Inspired by projects like OpenMW, OpenSkyrim modernizes Bethesda game files (.esm, .bsa, .nif, .dds, .pex) into ultra-fast, GPU-native formats (glTF 2.0, KTX2 Basis, libSQL / SQLite3, Luau) to deliver 60+ FPS high-performance gameplay without loading screens.

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✨ Features & Architecture Highlights

• 🚀 Zero Loading Screens: Interior and exterior city transitions load 100% seamlessly in real time using libSQL spatial R-Tree indexing and rkyv zero-copy memory mapping.
• ⚡ High-FPS Vercidium Rendering: Batched instanced indirect draw calls (DrawMeshInstancedIndirect) reduce 5,000+ individual draw calls to under 100 per frame.
• 📜 Luau Scripting Engine (mlua): Replaces single-threaded Papyrus with sandboxed, JIT-compiled Luau scripts. Includes async HTTP networking for live web APIs (e.g. real-world weather sync mods).
• 📱 Cross-Platform (Desktop & Mobile): Native support for Windows, Linux, macOS (Apple Silicon), and Android (ARM64 / POCO F5).
• 🎨 Modern UI (Bevy 0.19 bsn!): Transpiles obsolete Flash (.gfx) menus into hardware-accelerated declarative Bevy UI node trees.
• 🎮 Integrated Mod Manager: Built-in launcher with drag-and-drop archive installation and priority-weighted .esp/.esl plugin load orders.

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🏗️ Workspace Crate Architecture

OpenSkyrim is organized into a modular 3-crate Cargo workspace:

OpenSkyrim/
├── Cargo.toml                  # Workspace Root Manifest
├── crates/
│   ├── launcher/    # GUI Setup Wizard & Built-in Mod Manager
│   ├── converter/   # Converter Pipeline (.nif ➔ .glb, .dds ➔ KTX2, .esm ➔ libSQL)
│   └── engine/      # Bevy Game Engine Binary (Render, Physics, Luau, Audio)

Crate	Responsibilities
launcher	First-run setup wizard, game path detection, built-in mod manager UI, triggers converter progress bar, and launches the engine.
converter	Heavy offline asset converter (mesh-tools, basis-universal, ddsfile, nom binary parsers).
engine	Lightweight, hyper-fast game binary (Bevy 0.19+, wgpu, libsql, mlua Luau JIT).

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🗺️ Project Roadmap

OpenSkyrim is being built systematically across 5 core phases. Explore the full roadmap specs in docs/roadmap/.

• Phase 1: Asset Modernization Pipeline (converter) — Transpile legacy .esm, .nif, .dds, and .pex into SQLite 3, glTF 2.0, KTX2, and Luau.
• Phase 2: Core Engine Runtime & Vercidium Renderer (engine) — Runtime, integration, profiling, and acceptance infrastructure implemented; complete real-asset sign-off remains pending.
• Phase 3: Luau Runtime, Declarative UI & Launcher (launcher) — Sandboxed Luau JIT with async web APIs, Flash-to-Bevy bsn! UI conversion, and setup wizard.
• Phase 4: Gameplay Mechanics, Physics & Persistence — Rapier 3D physics, animation blending, combat state machine, and sub-second save state snapshots.
• Phase 5: Hardware Ray-Tracing, Multiplatform & Networking — WebGPU/Vulkan RTGI, DLSS/FSR3 frame gen, native co-op multiplayer, Android ARM64, and OpenXR VR.

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🚀 Quick Start (Development Setup)

Prerequisites

• Rust (2024 Edition)
• CMake & Ninja / GCC (for native libSQL / SQLite compilation)

Building & Running

1. Clone the repository:

   git clone https://github.com/your-username/OpenSkyrim.git
   cd OpenSkyrim

2. Check workspace compilation:

   cargo check --workspace

3. Run the Launcher App:

   cargo run -p launcher

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📚 Technical Specifications (docs/specs/)

For detailed technical specifications, format breakdowns, and architectural guidelines, explore the docs/specs/ directory:

• architecture.md — Core engine architecture overview & phase milestones.
• nif-to-gltf.md — 3D mesh converter specification (mesh-tools).
• dds-to-ktx2.md — Texture compressor specification (basis-universal + ddsfile).
• esm-to-sqlite.md — Master database specification (libSQL + rkyv).
• pex-to-lua.md — Papyrus bytecode to Luau transpilation spec (mlua).
• mods-and-ui.md — Integrated Mod Manager & Flash-to-Bevy UI strategy.
• launcher.md — First-run setup wizard & launcher workflow.
• vercidium-optimizations.md — High-FPS GPU instancing & HZB culling.
• platforms.md — Target matrix for Desktop, Mobile ARM64, and WebGPU.
• requirements.md — Hardware system specs and optimization analysis.
• features.md — Unlocked capabilities (Zero-loading screens, AI dialogue, native co-op).
• bevy-examples.md — Mapping official Bevy 0.19 patterns to engine subsystems.

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🤝 Contributing

We welcome community contributions! Whether you're fixing bugs in asset converters, enhancing Bevy rendering pipelines, or writing documentation, check out our guidelines before submitting a PR:

• 📖 CONTRIBUTING.md — Guide on development workflow, code style (cargo fmt/clippy), and PR guidelines.
• 🐛 Issue Tracker — Search existing issues or report a new bug using our template.

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⚖️ Legal Disclaimer & License

Licensing

OpenSkyrim is dual-licensed under either of the following licenses at your option:

• MIT License (LICENSE-MIT)
• Apache License, Version 2.0 (LICENSE-APACHE)

Legal Disclaimer

OpenSkyrim is an independent open-source game engine reimplementation. It does not contain any copyrighted game assets, artwork, 3D models, audio, or game data from Bethesda Softworks LLC or ZeniMax Media Inc. Users must supply their own legally owned copy of The Elder Scrolls V: Skyrim to extract game data.