Resolution Mod
From Thief Wiki
DDFix is a patch (created by TimeSlip) to allow Dark Engine games to run properly on modern hardware. It fixes the numerous problems introduced in modern graphics card drivers, as well as enabling 32-bit rendering to increase visual quality beyond even the original game. In addition, menus and books/scrolls are no longer displayed in a hard-coded 640x480 resolution, but are instead displayed at the same resolution as the game, removing the annoying resolution-switching that has always plagued Thief.
The Thief 2 version of DDFix also supports additional features, such as support for high-resolution override textures, that can go beyond the Dark Engine's 256x256 maximum texture size.
