Recs.
Updated
Orx is an open source 2D-oriented, data-driven, portable game engine focused primarily on ease of use and powerful features. It is written in C.
SpecsUpdate
Pros
Pro Data-oriented
Easy to create complex game elements such as objects, sound, event tracks, physics shaders, etc as simple text configuration which can be easily accessed in c++ on the code side. Faster than editing tools.
Pro Custom shader support
GLSL code can be added straight into data configuration files and can be applied to any texture: background or objects whivh allows for some amazing effects. All GLSL versions are supported, again by providing the shader language version in your configuration file.
Parameters are supported and values over time for shader animation.
Cons
Con Missing tools dedicated to content building
Although Orx's data configuration system, makes this largely redundant even though editor tools would be welcome by many.