In a post yesterday on the Mozilla blog, Epic Games and Mozilla revealed the first glimpse of Unreal Engine 4 running within Firefox via a rather understated video featuring two of Epic’s demos seemingly running in a Firefox window.
Video below the link.
Mozilla last year revealed Unreal Engine 3 running in Firefox (you can watch the demo for it here), and in the intervening time one commercial 3D release has been made, Monster Madness. Epic has seen some real competition in the online space from Unity, and Unreal Engine 4 running at near-native speeds on the web certainly ups the stakes. However, while both versions of the Unreal Engine offer significant benefits, until such a time that Epic offers an Unreal Development Kit (UDK) version for Unreal Engine 4 with wider cross-platform capabilities than those currently available in UDK, it’s likely that Unity will continue to gain momentum amongst online developers.
Source: Mozilla Blog