RoseThorn is a cross-platform library for 2D and 3D games running on GNU/Linux (and possibly other Unix-like OSes) and Windows. Features include: hardware accelerated 2D and 3D rendering; Ogg and WAV Sound support with OpenAL; Lua scripting; BMP, JPEG, and PNG image loading and saving (from screenshots); easily created and modified user interfaces with XML and CSS, combined with Lua event handling; separate 2D and 3D libraries; support for multiple fonts in both TTF and bitmap formats; support for OBJ, 3DS, MD5, and RTM model formats; skeletal animation (a work in progress); support for UDP and TCP networking; thread and mutex support; a Simple Shader API; 2D animated sprites; and some basic cryptography support. There is simple event management, with key/mouse bindings easily customized from the in-game console, config file, command line, or GUI.
TSDL was written for the turn-based strategy game "Turious", but is a stand alone library. It provides a number of useful widgets and event handling functions. Its widgets include container, label, button, text, numbox, checkbox, and console. All of the widgets can be given individual background images and custom text. Containers and widgets can be shown and hidden individually, and will retain their visibility state. The library uses OpenGL for rendering, allowing it to be used in 3D games as well as 2D.
The configure file is included in the download at http://sandbox.ltmnet.com/csvdb but if you're downloading from github you'll need to run `autoreconf -i' to generate one.