NVIDIA and Epic Games announced the first public showing of Unreal Engine 3 at this week's Electronic Entertainment Expo (E3). Unreal Engine 3 is the first game engine to take full advantage of Shader Model 3.0, a key feature of Microsoft DirectX 9.0. No points for guessing which graphics manufacturer is the only one with a product currently supporting SM 3.0. Created by Epic Games, Unreal Engine 3 promises to push the limits of game development with its aggressive use of lighting and shadowing…