14 DAY TRIAL // A few weeks back, Mozilla showed off the Unreal Engine 3 running in Firefox with completely standard, off the shelf technologies. It was made possible with Emscripten, which converts the C++ code to JavaScript, and with the support for Asm.js in Firefox.
But an actual working demo wasn't made available. It is now; the demo is online and, if you're running Firefox 23 Nightly, you'll be able to experience it in all its glory.
It will work in older Firefox versions, and even in other browsers; it's just standard web technology. But you'll get the best results in Firefox. In fact, it will probably crash in Chrome.
This is a non-interactive demo, you'll just see the Unreal Engine 3 rendering an environment as the demo runs its course. But it's all done in real time, the performance is very close to that of native apps, and it all works with no plugins.
What's more, Epic, makers of Unreal Engine, didn't actually have to do a lot of work to get it running in Firefox.
The complex C++ code was converted to JavaScript via Emscripten and it then worked as expected. The key though was Asm.js, a subset of JavaScript that only uses a few features but can be highly optimized.
Firefox 23's JavaScript engine supports Asm.js, giving the demo a huge speed boost over previous versions, but Firefox 23 also comes with support for Web Audio API, which handles all the audio in the demo. If you want to give it a try, be prepared to wait a bit while it loads.
If you don't have Firefox 23 or the patience to run it yourself, you can check out the video below to see it in action in Firefox.
Apart from the Epic Citadel demo, there's also a fully interactive Sanctuary demo, from the Unreal Tournament game, but it's not being released right now. Gameplay footage from that is available in the video as well.
