Wraith Engine

A distributed game engine with a browser-based collaborative editor

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Overview

Wraith Engine is a C++/Vulkan game engine runtime paired with a browser-based editor shell. The engine runs headless on a server, streams rendered viewports to browser clients via WebRTC with H.264, and processes editing commands through an authoritative command/event model. One shared runtime supports both local native editing and remotely hosted collaborative sessions.

Architecture

Browser (React / Next.js)
  ├─ Editor UI  (outliner, inspector, toolbar, content browser)
  └─ WebRTC Viewport Client
          ↕  commands  /  H.264 video
AxiomRemoteViewportServer  (C++)
  └─ EditorSession  (authoritative scene state)
          ├─ Vulkan Renderer  (offscreen, per-client)
          └─ ScriptHost  (Coral .NET 9 / C# scripting)

Features

Engine

• Vulkan rendering backend with MoltenVK on macOS
• Headless offscreen rendering with H.264 encoding (VideoToolbox on macOS)
• Authoritative command/event model for scene mutations
• DataModel scene hierarchy — folders, meshes, lights, cameras, actors
• Transform gizmos (translate / scale / rotate) with server-side hit-testing
• Multi-client rendering: each connected user gets their own viewport
• WebRTC streaming to browser
• C# scripting via Coral (.NET 9, hot reload, two trust tiers)
• Scene persistence — scene.json save/load across restarts

Browser editor

• Dockable panels: outliner, details/property inspector, content browser, toolbar
• Scene outliner with drag-drop reparenting, inline rename, right-click context menus
• Object lifecycle: create, duplicate, delete
• Per-client gizmo mode (Q / E / R shortcuts)
• User presence and camera visualization
• Script class attachment and hot-reload button

Prerequisites

• CMake 3.10+
• Ninja (recommended; brew install ninja)
• C++20 compiler (Clang recommended; Apple Clang 15+ on macOS)
• Vulkan SDK / MoltenVK (macOS: brew install --cask vulkan-sdk)
• Node.js 18+ and pnpm
• macOS: Xcode command-line tools (required for VideoToolbox / WebRTC)

Optional, required only when the corresponding CMake flag is ON:

Feature	Requirement
C# Scripting (AXIOM_ENABLE_SCRIPTING)	.NET 9 SDK (brew install dotnet)
WebRTC transport (AXIOM_ENABLE_WEBRTC)	Pre-built WebRTC.framework or libwebrtc for macOS

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Build

Quick start (minimal — no scripting, no WebRTC)

cmake --preset debug
cmake --build build/debug

With C# scripting enabled

Build the managed assemblies first, then configure with the scripting flag:

# 1. Build Coral's managed runtime shim
dotnet build ThirdParty/Coral/Coral.Managed/Coral.Managed-Static.csproj -c Debug

# 2. Build the engine API assembly
dotnet build Scripting/WraithEngine.Managed/WraithEngine.Managed.csproj -c Debug

# 3. Configure and build
cmake --preset debug -DAXIOM_ENABLE_SCRIPTING=ON
cmake --build build/debug

With scripting + automatic hot reload (macOS only)

The file watcher uses kqueue to detect .dll changes and reload without restarting the server:

cmake --preset debug \
  -DAXIOM_ENABLE_SCRIPTING=ON \
  -DAXIOM_SCRIPTING_WATCH=ON
cmake --build build/debug

With WebRTC transport

Supply paths to a locally built WebRTC library or pre-built framework:

# Using a pre-built WebRTC.framework (macOS)
cmake --preset debug \
  -DAXIOM_ENABLE_WEBRTC=ON \
  -DAXIOM_WEBRTC_FRAMEWORK_PATH=/path/to/WebRTC.framework

# Using a static libwebrtc binary
cmake --preset debug \
  -DAXIOM_ENABLE_WEBRTC=ON \
  -DAXIOM_WEBRTC_LIBRARY_PATH=/path/to/libwebrtc.a \
  -DAXIOM_WEBRTC_INCLUDE_DIR=/path/to/webrtc/include

With tests

cmake --preset debug -DBUILD_TESTING=ON
cmake --build build/debug
ctest --test-dir build/debug

To include the scripting tests:

dotnet build ThirdParty/Coral/Coral.Managed/Coral.Managed-Static.csproj -c Debug
dotnet build Scripting/WraithEngine.Managed/WraithEngine.Managed.csproj -c Debug
dotnet build Tests/TestScripts/WraithTestScripts/WraithTestScripts.csproj -c Debug
dotnet build Tests/TestScripts/WraithRestrictedScript/WraithRestrictedScript.csproj -c Debug

cmake --preset debug -DBUILD_TESTING=ON -DAXIOM_ENABLE_SCRIPTING=ON
cmake --build build/debug
ctest --test-dir build/debug

Release build

All flags above work with the release preset:

cmake --preset release -DAXIOM_ENABLE_SCRIPTING=ON
cmake --build build/release

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CMake Options Reference

Option	Type	Default	Description
BUILD_TESTING	BOOL	OFF	Build the Google Test suite
AXIOM_ENABLE_SCRIPTING	BOOL	OFF	Enable the Coral C# scripting host (.NET 9)
AXIOM_SCRIPTING_WATCH	BOOL	OFF	Auto-reload user scripts on disk change (macOS kqueue). Requires AXIOM_ENABLE_SCRIPTING=ON
AXIOM_SCRIPTING_TRUST_DEFAULT	STRING	Restricted	Default sandbox tier for user scripts. Restricted (hosted — blocks System.Net.*, System.Reflection.Emit, etc.) or Trusted (local dev — full BCL access)
AXIOM_ENABLE_WEBRTC	BOOL	OFF	Enable the macOS WebRTC transport
AXIOM_WEBRTC_FRAMEWORK_PATH	PATH	(empty)	Path to a WebRTC.framework bundle (macOS framework variant)
AXIOM_WEBRTC_LIBRARY_PATH	FILEPATH	(empty)	Path to a libwebrtc static/shared binary (non-framework variant)
AXIOM_WEBRTC_INCLUDE_DIR	PATH	(empty)	Include directory for the non-framework libwebrtc variant

Trust profiles — applies only when AXIOM_ENABLE_SCRIPTING=ON:

Profile	Intended use	What it blocks
Restricted	Hosted / cloud sessions	System.Net.*, System.Net.Sockets, System.Reflection.Emit, System.Diagnostics.Process, dynamic assembly loading
Trusted	Local dev, native editor	Nothing — full BCL available

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Running

Remote viewport server

./build/debug/Headless/AxiomRemoteViewportServer \
  --host 127.0.0.1 --port 8080 --width 1280 --height 720

Browser editor

cd EditorFrontend
pnpm install
NEXT_PUBLIC_AXIOM_SERVER_ORIGIN=http://127.0.0.1:8080 pnpm dev

Open http://localhost:3000 in your browser.

Local native editor (no browser required)

./build/debug/Editor/AxiomEditor

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Project Structure

Path	Contents
Axiom/	Engine library — core, session, renderer, remote transport, scripting host
Editor/	Native GLFW + ImGui editor executable
Headless/	Headless runtime and AxiomRemoteViewportServer
Scripting/WraithEngine.Managed/	C# engine API assembly (Script, GameObject, Transform)
EditorFrontend/	React / Next.js browser editor shell
Content/	Shaders, demo assets (.glb), and the persistent scene.json
Tests/	Google Test suite
Tests/TestScripts/	C# test assemblies for scripting tests
Docs/	Architecture and design documents
ThirdParty/	Vendored dependencies (Coral, spdlog, glfw, fastgltf, glm, …)
cmake/	CMake helper modules

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Tech Stack

Layer	Technology
Engine	C++20, CMake, Vulkan
Windowing	GLFW, MoltenVK
Asset loading	fastgltf (glTF / glb)
Streaming	WebRTC, H.264 (VideoToolbox)
Scripting	Coral — C++ ↔ .NET 9 host bridge
Managed scripting API	C# (.NET 9), WraithEngine.Managed
Browser editor	React 19, Next.js, TypeScript
Styling	Tailwind CSS, Radix UI
Testing	Google Test
Logging	spdlog

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License

MIT — see LICENSE.