NEKU ENGINE

Ultra-lightweight 2D/3D game & app engine with a professional pixel-UI Studio (desktop + browser), internet co-op, CRT effects, and one-click exports to web, itch.io, and native desktop apps. Mascot: cwat >w<.

• A complete 2D game exports to a ~50 KB single HTML file (3D games ≈ 1 MB with Three.js embedded) — or to runnable macOS / Windows / Linux apps, straight from the Studio, no tooling installed.
• Neku Studio runs in any browser and as a 1–2 MB native app for macOS / Windows / Linux (grab it from Releases).
• Hosted browser Studio: deviverr.github.io/NEKU-Engine/editor/.
• Co-op from anywhere: host a session, share a 5-letter room code, teammates join from the web or desktop Studio on any platform — no server to run.
• Runtime dependencies: zero. Three.js, cannon-es and CodeMirror are vendored, pinned files — npm install is never required to use, edit, or ship a game.

Highlights

2D + 3D in one scene	Canvas2D UI over a Three.js world — or on it: Screen3D maps the live 2D scene onto any mesh and clicks pass through (the Casino Calculator arcade-cabinet trick, built in).
Physics	2D arcade physics (gravity, AABB, collision signals, tilemap colliders) + full 3D rigid bodies via cannon-es (mass, friction, restitution, stacking) — each loads only when used.
Studio	Real menu bar (File/Edit/View/Project/Tools/Help) · boot splash · status bar · dockable panels + layout presets · modal dialogs & toasts (no browser popups) · Explorer · live Errors panel · Output log · Timeline keyframe editor · CodeMirror 6 scripting with Neku autocomplete · play-mode debug bar.
3D editing	Move/rotate/scale gizmos (W/E/R) · orbit camera · click-select · snapping · focus (F) · visible camera & light markers · material sliders (metalness/roughness/emissive/opacity) · GLTF model import.
Paint 2.0	Built-in pixel editor: layers, pencil/fill/line/rect/circle/select-move, undo/redo, content-preserving resize, spritesheet frames with animated preview + onion skin, edit any texture via ✎ in the Inspector.
Co-op	Roblox-style Team Create over the hosted Neku relay (Cloudflare, free) — host, share the room code, done. Assets sync separately from edits, chunked, so keystrokes stay light. Self-host with npm run coop for LAN/offline.
Exports	Single HTML file · itch.io ZIP · native desktop apps for macOS / Windows / Linux (Neutralino shell, built entirely in the Studio — even the hosted one).
Looks	7 pixel themes + a custom theme editor (shareable .nkt files), CRT post-FX (curvature/scanlines/vignette/glow/aberration), synthesized SFX — games ship no audio files.
Extendable	.nkx plugins add themes, templates, and tools to the Studio via a tiny neku.register* API.

Quick start

Desktop: download your OS zip from Releases, unzip, run. (macOS: right-click → Open the first time. Linux: needs libwebkit2gtk.)

Browser:

git clone https://github.com/deviverr/NEKU-Engine
cd NEKU-Engine
npm start        # → http://localhost:8347/editor/

Try the Neku Arcade sample from the main menu: a 3D room where the arcade cabinet's CRT is a live, clickable 2D slot machine — one scene that shows off most of the engine. Help → Cheatsheet (or ?) for the full API, or read docs/API.md.

Make → ship

1. Pick a template (Blank / 2D Game / 3D Game / App) in the main menu.
2. Build scenes in the 2D/3D viewports; script nodes in plain JavaScript (self = node, game = engine); animate on the Timeline; draw sprites in Paint.
3. File → Export → HTML file, itch.io ZIP, or Desktop apps (mac/win/linux zips with your game's name and icon). Publishing walkthroughs: docs/PUBLISHING.md.

Team Create (co-op)

Click ◉ Co-op → Host new session and share the room code. Teammates click Join with the code — from the hosted Studio, a local clone, or the desktop app, on any OS. Live edits, colored selections, per-peer presence. Rooms live on the hosted relay (relay/ — a tiny Cloudflare Durable Object, deploy your own with npm run relay) and clean themselves up after a week of inactivity. Offline/LAN: npm run coop and point the Co-op window at ws://YOUR-LAN-IP:8348.

File formats

.neku/.nk project · .nkp prefab · .nkt theme · .nkx Studio plugin — all JSON/JS, all diff-friendly, all openable from the Studio.

Repo layout

engine/    runtime — core, renderer2d, render3d (Three), physics2d, physics3d (cannon),
           fx (CRT), audio synth, input, bundler (exports), desktop-export (asar+zip)
editor/    Neku Studio — menubar, dock, dialogs, viewports (2D + gizmo 3D), timeline,
           paint 2.0, panels, settings (Preferences + Project Settings), co-op client
desktop/   Neutralino shell + cwat icons + player binaries  →  npm run desktop
relay/     hosted co-op relay (Cloudflare Worker + Durable Object)  →  npm run relay
vendor/    three.js (+Orbit/Transform controls, GLTFLoader) · cannon.js · codemirror.js
projects/  samples: neku-arcade · neku-breakout · casino-calculator
tools/     serve · co-op server · export CLIs · vendor/sample/desktop/pages builders
docs/      API.md · PUBLISHING.md · PLAN.md

For testers

Desktop zips are on the Releases page along with playable sample exports. Bug reports → GitHub issues. Things to poke: paint a layered sprite, gizmo a mesh around in 3D, host a co-op room and join it from your phone's browser, export your game as a desktop app and double-click it.

Roadmap (post-2.0)

• Op-based co-op merging (currently last-write-wins)
• GLTF skeletal animation controls · custom shader nodes
• TypeScript definitions in the script editor
• In-Studio relay room browser

MIT. Made for shipping silly ideas fast. >w<