xSGE ("Extensions for the SGE") is a collection of modules that make doing certain tasks with the SGE Game Engine easier. They are licensed under the GNU General Public License, which means that xSGE components, unlike the SGE itself, are only for use by libre software games.
On top of the benefits of the SGE, xSGE components provide the following features:
- GUI toolkit: A simple, lightweight widget toolkit for use with your games is provided by the xsge_gui module.
- Lighting framework: xsge_lighting lets you easily add lighting in any color or mix of colors you want.
- Physics framework: Get unisolid walls, slopes, moving walls, and even moving slopes in the easy-to-use xsge_physics module.
- TMX support: Easily load maps created with the Tiled map editor with the xsge_tmx module.