Built with Claude Opus 5.5 + UE5 + WebGPU. If you have a Unreal game you want to bring to the browser, please lmk!
2,750 karma · joined May 4, 2019
Also just a suggestion - try not to hate on others so much, it'll make your life more pleasant!
We spent the last several years building out a WebGPU RHI for UE5, along with tooling to make games load fast using asset streaming, while using less memory. We were recently featured by Gamesbeat.
You can read more about it below or check out our website:
https://gamesbeat.com/simplystream-unlocks-web-compatibility...
X link: https://x.com/AlexStLouis10
It's fully playable in the browser, no install or plugins. Pick a map like g-23 to drop into a match against bots.
Some of the technical work I wanted to highlight that I/Claude focused on that went into making it actually fast:
- The engine runs off the main thread. DarkPlaces is compiled to WASM/WebGL2, but the whole engine runs on a worker via Emscripten's PROXY_TO_PTHREAD, with the WebGL context owned directly by the worker through an OffscreenCanvas (zero cross-thread GL dispatch). That let me remove Asyncify entirely — the payoff is a steady frame loop (~4 ms/frame, 99.8% of frames under 16 ms in a profiled match).
- GPU texture transcoding. Every texture is Basis Universal / KTX2, transcoded at load time to whatever compressed format your GPU supports (BC7 on desktop, etc). That took the texture set from ~5.3 GB of TGAs down to a few hundred MB on disk and cut GPU memory ~4×. Audio is re-encoded to Ogg Vorbis.
- Streamed on-demand filesystem. Nothing is bundled. The engine reads through a virtual filesystem backed by Cloudflare R2; only a tiny boot set loads upfront, then each map prefetches its working set in parallel and streams the rest as surfaces actually draw. A full map's assets dropped from ~2.3 GB to ~320 MB per session.
- SIMD. Built with -msimd128, so the math and skeletal-animation paths vectorize to wasm128.
- Hosting. Cloudflare R2 (zero egress) behind a Worker, with COOP/COEP headers for SharedArrayBuffer/threads. Assets are immutable-cached and the engine binary revalidates, so reloads are cheap.
Multiplayer is peer-to-peer. Click Host Game and you get a 6-character invite code; a friend enters it and you connect directly browser-to-browser over a WebRTC DataChannel (configured unreliable/unordered to match the engine's UDP netcode).
A tiny Cloudflare Worker only relays the one-time WebRTC handshake — once you're connected, no game traffic touches any server. I tested a real 1v1 between Edmonton and Bangkok and it held up across the Pacific.
Would love feedback, so please report any bugs or glitches here and I'll patch asap.
The game that this prompt generated looks pretty decent visually. A big part of this likely due to the fact the meshes were created using a seperate tool (probably meshy, tripo.ai, or similiar) and not generated by 5.5 itself.
It really seems like we could be at the dawn of a new era similiar to flash, where any gamer or hobbyist can generate game concepts quickly and instantly publish them to the web. Three.js in particular is really picking up as the primary way to design games with AI, in spite of the fact it's not even a game engine, just a web rendering library.
If it does crash, you'll be able to see why. I'd be interested in seeing any bug reports if you do fine some, we're always squashing bugs over here!
My company is working to bring Unreal to the browser, and we've built out a custom WebGPU RHI for Unreal Engine 5.
Here are demos of the tech in action, for anyone interested:
(Will only work on Chromium-based browsers on desktop, and on some Android phones)
Cropout: https://play-dev.simplystream.com/?token=aa91857c-ab14-4c24-...
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