GemRB (Game engine made with pre-Rendered Background) is a portable open-source implementation of Bioware's Infinity Engine.

This indeed describes the fundamental characteristics of Infinity Engine-based games: The world, or more correctly the areas where you move, be it cold empty plains of Icewind Dale, busy streets of Waterdeep or damp catacombs under Sigil, was painted and/or rendered in advance, during game development, into a series of static pictures.

It was written to support pseudo-3D role playing games based on the Dungeons & Dragons ruleset (Baldur's Gate and Icewind Dale series, Planescape: Torment). It should run on GNU/Linux, Microsoft Windows, OS X, possibly other UNIX derivatives and more.

The first one, GUIScript, concerns mostly with game GUI, i.e. user interaction, opening and closing windows, pushing of character sheet buttons, inventory, etc. This functionality has been hardwired in the original games (probably with Lua scripts compiled-in into the main EXE) and so we need to implement it anew. GUIScript scripts have to be tailored for each game type, because each game uses more or less different GUI, string refs, and so on.

The license of this software is Free, you can free download and free use this game utility software.