XEngine

An AI-native, Unity-like game engine written in pure C# on .NET 10.

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🎉 V1.0.0f1 — officially open source under MIT. First official release.

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_{XEngine Editor V1.0.0f1 · Vulkan backend · voxel world from the built-in com.xengine.voxelworld package}

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🎮 What is XEngine

XEngine is an open source, MIT-licensed real-time 2D/3D engine — runtime, editor and toolchain — written entirely in modern C# on .NET 10 / CoreCLR. It mirrors the Unity mental model (GameObject + MonoBehaviour, Scene/Hierarchy/Inspector/Project/Console/Game views, prefabs, .meta GUID assets) so Unity developers can move over without relearning the fundamentals — while staying small, readable, hackable and free of engine licensing fees.

Two things make it more than a Unity clone:

• The engine is designed for AI agents as first-class users. MCP is built into the kernel, not bolted on. An agent can read and edit scenes, assets, animation graphs, shaders and code, run the project, take screenshots and verify results — through a typed, risk-classified tool surface.
• Every source asset is human-readable text. Scenes, prefabs, shader graphs, VFX graphs, timelines and settings are text that git diff can show and an agent can safely edit.

using XEngine.Runtime;
using XEngine.Vector;

public class Spinner : MonoBehaviour
{
    public float DegreesPerSecond = 90f;

    public override void Update()
    {
        Transform.Rotate(new Float3(0f, DegreesPerSecond * Time.DeltaTime, 0f));
    }
}

Scale: ≈680,000 lines of first-party C# across 3,000+ files, exercised by 6,000+ automated tests. Full module inventory: docs/features.md.

✨ Highlights

• 🤖 AI-native by design — dual MCP channels: 120+ offline host tools (xengine-cli) plus 20+ in-editor runtime tools (--serve), with four-level RiskLevel, dryRun previews, hash pre-checks, idempotency keys and a provenance journal. 40+ authoring skills in cli/skills/.
• 📝 Text-first assets — .scene, .prefab, .shadergraph, .vfx, .timeline, .volumeprofile are all diffable text; merge conflicts are readable and agents can patch surgically.
• 🎨 One RHI, six backends — D3D12 · Vulkan · OpenGL · Metal · WebGPU · WebGL2 behind a single abstraction, with a URP-aligned pipeline (Forward+, STP, SSGI, DDGI realtime GI, Virtual Geometry, Shader Graph).
• ⚡ Measured performance — zero-allocation XTask async, Roslyn analyzers (PR0001–PR0007) that make hot-path allocation a compile error, performance contract tests, byte-exact screenshot regression.
• 🧱 Self-contained third party — companion libraries vendored as source in ThirdParty/; NuGet dependencies come from nuget.org only — no private feeds.

📸 Gallery

Frame Debugger	Game view + render stats
Event tree, render-target channel preview, per-event render state.	Full-HD game view with draws / batches / tris / lights / shadow-pass breakdown.

Spine runtime	Timeline · Package Manager
Spine skeletal 2D animation playing in the editor.	Multi-track cutscene editing with signals, alongside package management.

Animator + animation workflow	Device simulator · backend switching
Animator state machine docked with Scene, Game, Hierarchy and Inspector.	Real-device-resolution preview with safe area; pick a backend in Preferences or --graphics=vulkan|d3d12|opengl.

🌍 Platform support

Platform	Status	Notes
Windows	✅ Shipping	Editor and player; D3D12 / Vulkan / OpenGL
Linux	✅ Shipping	Editor and player; Vulkan / OpenGL
macOS	✅ Shipping	Editor and player; Metal backend in bring-up
Android	✅ Shipping	APK / AAB build and --build-and-run deployment, Vulkan with realtime shadows
HarmonyOS	🔧 In progress	Vulkan RHI baseline, NAPI host, Hvigor project generation, HAP/APP packaging; compatibility acceptance ongoing
WeChat / Douyin mini games	🔧 In progress	Mini-game project generation, WASM loading ABI, subpackage CDN; renders in WeChat DevTools
iOS	🔧 In progress	Build pipeline skeleton in place; blocked on the Metal backend
WASM (standalone)	⬜ Planned	Depends on the WebGPU backend

HarmonyOS 6.1 device	Android arm64	WeChat DevTools

🧱 Architecture

XEngine.sln                            # abbreviated — open it for the full project graph
├── XEngine.Runtime/                   # Runtime core — shippable standalone, zero editor dependencies
├── XEngine.Editor/ (+ .UI, .UI.Rendering)   # Editor executable and UI framework
├── XEngine.Runtime.Test/ · XEngine.Editor.Test/ · XHub/ (+ Test)
├── Tools/                             # Analyzers · Ai.Host (MCP CLI) · Ai.Server · Ai.Gateway ·
│                                      # Data.Provenance · PackageRegistry · platform toolchains
├── Packages/                          # 38 first-party packages (com.xengine.*)
├── ThirdParty/                        # Vendored source: Echo · Vector · Paper/Origami · Quill/Scribe ·
│                                      # Clay · Photonic/Unwrapper · Jitter2 · Slang · Rosetta · DotRecast
├── Libraries/                         # Native libraries per RID (FFmpeg, miniaudio)
├── cli/skills/                        # Agent authoring skills
└── docs/                              # Feature tour (features.md) and screenshots

🚀 Getting started

• .NET 10 SDK and a GPU with Vulkan, D3D12 or OpenGL 4.1+ support (IDE: Visual Studio 17.8+, VS Code or Rider)

dotnet restore XEngine.sln
dotnet build XEngine.sln -c Debug
dotnet run --project XEngine.Editor                 # or: --graphics=vulkan|d3d12|opengl

Connect an AI agent — point any MCP client at the offline host (xengine-cli), or start the editor with --serve to expose the runtime tools as well. Skills in cli/skills/ document each workflow. NuGet dependencies resolve from nuget.org; companion libraries are vendored in ThirdParty/ as source.

📌 Project status

V1.0.0f1 — first official open source release. Runtime, editor, renderer, physics, audio, animation, UI and asset pipeline are all rewritten and exercised by 6,000+ automated tests. APIs will still change, some subsystems (Metal, WebGPU/WebGL2, iOS, HarmonyOS acceptance) are in bring-up, and the ecosystem is young. It is meant for people who want to build with — or on — an engine they can read end to end.

🧭 Roadmap

Area	Next up
Rendering	Metal backend (unblocks iOS), SRP batcher, GLES3 mobile tuning, adaptive performance, FSR upscaling
Platforms	HarmonyOS compatibility acceptance and Beta, mini-game package-size gate, iOS export, standalone WASM
Gameplay	Animation rigging / runtime IK, behaviour trees
Networking	Multiplayer runtime (NetworkManager / NetworkBehaviour, pluggable transports) — design phase
Data	Addressables-style addressed loading with groups and remote CDN
Tooling	Presets, quick search, grid & snap, project auditor, recorder, visual scripting, in-editor version control
Performance	Job system for data parallelism, ECS evaluation, NativeAOT + intrinsics as a Burst equivalent

Explicitly out of scope: XR/AR/VR, cloud gaming services, legacy deprecated stacks.

🤝 Contributing

Contributions are welcome — please read CONTRIBUTING.md and CODE_OF_CONDUCT.md first. Before touching code, read the matching skill guide under skills/ (LINQ / hot-path / rendering / performance validation). Do not relax an analyzer rule or widen an allow-list without benchmark evidence and matching tests.

🙏 Acknowledgments

• Prowl Game Engine by Michael Sakharov / Wulferis (MIT) — XEngine evolved from Prowl's core architecture and render pipeline.
• Anthology by Wulferis (MIT) — Echo, Paper, Origami, Quill, Scribe, Clay, Vector, Photonic, Unwrapper, Rosetta and Slang are vendored as source under ThirdParty/.
• Raylib — Prowl's early foundation.
• Design references: YooAsset (Apache 2.0) and Unity ScriptableBuildPipeline inspired the AssetBundle system's design (independently reimplemented under MIT).

Key dependencies: Silk.NET, Vortice.Direct3D12, Jitter Physics 2, Box2D.NET, Magick.NET, Slang, K4os.Compression.LZ4, DotRecast, spine-csharp. Full notices: THIRD_PARTY_NOTICES.md.

Prowl contributors whose work XEngine inherits: Michael (Wulferis) · Abdiel Lopez · Josh Davis · ReCore67 · Isaac Marovitz · Kuvrot · JaggerJo · Jihad Khawaja · Jasper Honkasalo · Kai Angulo · Bruno Massa · Mark Saba · Chandler Cox · EJTP · Paolo · Kouame Benoit Junior Augustin

📜 License

XEngine is distributed under the MIT License — see LICENSE. It derives from Prowl Game Engine (MIT) and vendors its Anthology companion libraries and the Slang compiler's native libraries (MIT); upstream notices are preserved in full in THIRD_PARTY_NOTICES.md.

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_{XEngine — built for developers, and for the agents working alongside them.}