OpenGL topic
OpenGL (Open Graphics Library) is the computer industry’s standard API for defining 2-D and 3-D graphic images. OpenGL allows new hardware innovations to be accessible through the API via the OpenGL extension mechanism. It is used in CAD (Computer-aided design), virtual reality, video games, and flight simulation.
duality
a 2D Game Development Framework
Celestia
Real-time 3D visualization of space.
OpenRCT2
An open source re-implementation of RollerCoaster Tycoon 2 🎢
xray-16
Improved version of the X-Ray Engine, the game engine used in the world-famous S.T.A.L.K.E.R. game series by GSC Game World. Join OpenXRay! ;)
teeworlds
A retro multiplayer shooter
opensoldat
OpenSoldat is a unique 2D (side-view) multiplayer action game
mlt
MLT Multimedia Framework
openspades
Compatible client of Ace of Spades 0.75
HybridRenderingEngine
Clustered Forward/Deferred renderer with Physically Based Shading, Image Based Lighting and a whole lot of OpenGL.