The Unreal Engine is a game engine developed by Epic Games, first showcased in the 1998 first-person shooter game Unreal. Although primarily developed for first-person shooters, it has been successfully used in a variety of other genres, including stealth, MMORPGs, and other RPGs. With its code written in C++, the Unreal Engine features a high degree of portability and is a tool used by many game developers today.
The current release is Unreal Engine 4, designed for Microsoft's DirectX 11 and 12 (for Microsoft Windows, Xbox One, Windows RT); OpenGL (for OS X, Linux, PlayStation 4, iOS, Android, Ouya and Windows XP); and JavaScript/WebGL (for HTML5 Web browsers).
Making its debut in 1998 with Unreal, the first generation Unreal Engine integrated rendering, collision detection, AI, visibility, networking, scripting, and file system management into one complete engine. Unreal Engine 1 provided an advanced software rasterizer and a hardware-accelerated rendering path using the Glide API, specifically developed for 3dfx GPUs, and was updated for OpenGL and Direct3D. The release of Unreal Tournament marked great strides in both network performance and Direct3D and OpenGL support.