Show HN: Mystral Native – Run JavaScript games natively with WebGPU (no browser)

[Flux159]

Hi HN, I've been building Mystral Native — a lightweight native runtime that lets you write games in JavaScript/TypeScript using standard Web APIs (WebGPU, Canvas 2D, Web Audio, fetch) and run them as standalone desktop apps. Think "Electron for games" but without Chromium. Or a JS runtime like Node, Deno, or Bun but optimized for WebGPU (and bundling a window / event system using SDL3).

Why: I originally started by starting a new game engine in WebGPU, and I loved the iteration loop of writing Typescript & instantly seeing the changes in the browser with hot reloading. After getting something working and shipping a demo, I realized that shipping a whole browser doesn't really work if I also want the same codebase to work on mobile. Sure, I could use a webview, but that's not always a good or consistent experience for users - there are nuances with Safari on iOS supporting WebGPU, but not the same features that Chrome does on desktop. What I really wanted was a WebGPU runtime that is consistent & works on any platform. I was inspired by deno's --unsafe-webgpu flag, but I realized that deno probably wouldn't be a good fit long term because it doesn't support iOS or Android & doesn't bundle a window / event system (they have "bring your own window", but that means writing a lot of custom code for events, dealing with windowing, not to mention more specific things like implementing a WebAudio shim, etc.). So that got me down the path of building a native runtime specifically for games & that's Mystral Native.

So now with Mystral Native, I can have the same developer experience (write JS, use shaders in WGSL, call requestAnimationFrame) but get a real native binary I can ship to players on any platform without requiring a webview or a browser. No 200MB Chromium runtime, no CEF overhead, just the game code and a ~25MB runtime.

What it does: - Full WebGPU via Dawn (Chrome's implementation) or wgpu-native (Rust) - Native window & events via SDL3 - Canvas 2D support (Skia), Web Audio (SDL3), fetch (file/http/https) - V8 for JS (same engine as Chrome/Node), also supports QuickJS and JSC - ES modules, TypeScript via SWC - Compile to single binary (think "pkg"): `mystral compile game.js --include assets -o my-game` - macOS .app bundles with code signing, Linux/Windows standalone executables - Embedding API for iOS and Android (JSC/QuickJS + wgpu-native)

It's early alpha — the core rendering path works well & I've tested on Mac, Linux (Ubuntu 24.04), and Windows 11, and some custom builds for iOS & Android to validate that they can work, but there's plenty to improve. Would love to get some feedback and see where it can go!

MIT licensed.

Repo: https://github.com/mystralengine/mystralnative

Docs: https://mystralengine.github.io/mystralnative/

[whizzter]

As a gamedev i love it, if you bet on JS for games and need "native" packaging then the platform runtimes has been quite a bit hit-or-miss but with V8 as default (or JSC) then it's sane runtimes with a good WebGPU backend (same as in the browsers).

Only thing "missing" is perhaps a companion builder to emulate the C++ API with a WKWebView bundling setup for iOS.

For those reading, if Apple still disallows JIT:ed code, then a WKWebView might still be the best option in terms of pure JS simulation performance even if the WebView might steal some GPU perf.

What's the story/idea on controls (thin DOM emulation for pointerevents,keyboard,etc?), accelerometers, input-fields and fonts.

As much as I like controlling what I render, having good support for font/input-handling and system inputs is a clear plus of using web tech.

[Flux159]

Hi, thanks! Yeah for controls I'm emulating pointerevents and keydown, keyup from SDL3 inputs & events. The goal is that the same JS that you write for a browser should "just work". It's still very alpha, but I was able to get my own WebGPU game engine running in it & have a sponza example that uses the exact key and pointer events to handle WASD / mouse controls: https://mystraldev.itch.io/sponza-in-webgpu-mystral-engine (the web build there is older, but the downloads for Windows, Mac, and Linux are using Mystral Native - you can clearly tell that it's not Electron by size (even Tauri for Mac didn't support webp inside of the WebGPU context so I couldn't use draco compressed assets w/ webp textures).

I put up a roadmap to get Three.js and Pixi 8 (webgpu renderer) fully working as part of a 1.0.0 release, but there's nothing that my JS engine is doing that is that different than Three.js or Pixi. https://github.com/mystralengine/mystralnative/issues/7

I did have to get Skia for Canvas2d support because I was using it for UI elements inside of the canvas, so right now it's a WebGPU + Canvas2d runtime. Debating if I should also add ANGLE and WebGL bindings as well in v2.0.0 to support a lot of other use cases too. Fonts support is built in as part of the Skia support as well, so that is also covered. WebAudio is another thing that is currently supported, but may need more testing to be fully compatible.

[Flux159]

Followup comment about Apple disallowing JIT - will need to confirm if JSC is allowed to JIT or only inside of a webview. I was able to get JSC + wgpu-native rendering in an iOS build, but would need to confirm if it can pass app review.

There's 2 other performance things that you can do by controlling the runtime though - add special perf methods (which I did for draco decoding - there is currently one __mystralNativeDecodeDracoAsync API that is non standard), but the docs clearly lay out that you should feature gate it if you're going to use it so you don't break web builds: https://mystralengine.github.io/mystralnative/docs/api/nativ...

The other thing is more experimental - writing an AOT compiler for a subset of Typescript to convert it into C++ then just compile your code ("MystralScript") - this would be similar to Unity's C# AOT compiler and kinda be it's own separate project, but there is some prior work with porffor, AssemblyScript, and Static Hermes here, so it's not completely just a research project.

[valorzard]

This is so interesting!! I had a very similar idea! I would love to see if you could port games made with phaser or three js to this engine (though I think anything that involves the DOM is a no go sadly)

[Flux159]

So I am stubbing parts of the DOM api (input handling like keydown, pointer events, etc.), so you shouldn't need to rewrite any of that.

Three.js and Pixi 8 with the WebGPU renderer are part of the v1.0.0 roadmap (verifying that they can work correctly on all platforms), right now most of the testing was done against my own engine (tentatively called mystral.js which will also be open sourced as part of v1.0.0, it's already used for some of the examples, just as a minified bundle): https://github.com/mystralengine/mystralnative/issues/7

[whizzter]

For any thin parts that needs the DOM one could make JS stubs that mimic behaviour.

[auyez]

Great project! I also had similar thoughts when I saw ability to make WebGPU calls in deno. I wonder how performant could games get on this runtime

[danjl]

Love it. Double bonus points if we could somehow add hardware ray tracing, which is missing from the browser WebGPU implementations. I'll definitely give this a shot with my 3D interactive WebGPU chessboard. A desktop implementation opens up the possibility of publishing on steam and other services which all expect a desktop app.

[Flux159]

So in theory it should be possible, but it might require customizing the Dawn or wgpu-native builds if they don't support it (this is providing the JS bindings / wrapper around those two implementations of wgpu.h). But I've already added a special C++ method to handle draco compression natively, adding some mystral native only methods is not out of the question (however, I would want to ensure that usage of those via JS is always feature flagged so that it doesn't break when run on web).

Did you write your WebGPU chessboard using the raw JS APIs? Ideally it should work, but I just fixed up some missing APIs to get Three.js working in v0.1.0, so if there are issues, then please open up an issue on github - will try to get it working so we close any gaps.

[rockyj]

Very interesting. It would be great if this works with a "higher" level library like Pixi.js or Phaser.js, that way one could build with ease in JS/TS, using a rich library/ecosystem and still distribute a "native" app (it probably already works with these libs but not sure).

[Flux159]

Phaser is not supported right now because phaser is still using a WebGL renderer from my understanding (maybe in a v2.0.0 adding ANGLE + WebGL support is an option, but debating if that's a good idea or not).

Pixi 8 has a WebGPU renderer so that should be supported as part of a v1.0.0 release - it's on the roadmap to verify that three and pixi 8 work correctly: https://github.com/mystralengine/mystralnative/issues/7

[TazeTSchnitzel]

Very cool! This reminds me of Ejecta, which was something like this for 2D games on iOS, a very long time ago: https://impactjs.com/ejecta

[Flux159]

I remember reading about Ejecta a long time ago! I had completely forgotten about it, but it is similar! The funny thing is to support UI elements, I had to also support canvas2d through Skia (although not 100% yet), so maybe impact could even work at some point (would require extensive testing obviously).

[iddan]

Cool project and very clear explanation for the motivation kudos!