Unreal Engine

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 otherRPGs. 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 10-12 (for Microsoft Windows, Xbox One, Windows RT); OpenGL (forOS X, Linux, PlayStation 4, iOS, Android, Ouyaand 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. Large parts of the game were implemented in a custom scripting language called UnrealScript. The initial network performance was also very poor when compared to its biggest competitor, Quake II. Epic used this engine for both Unreal and Unreal Tournament. The release of Unreal Tournament marked great strides in both network performance and Direct3D and OpenGL support.

The engine became very popular due to the modular engine architecture and the inclusion of ascripting language, which made it easy to mod, including total conversions like Tactical Ops.