C++ lightweight cross-platform game engine
Modified source engine (2017) developed by valve and leaked in 2020
A modern re-implementation of the classic DOS game Duke Nukem II
MIT Licensed Open Source version of Torque3D from GarageGames
Mini game engine for games104
Urho3D Game engine
Updated emulator of Forgotten Realms: Unlimited Adventures
A high speed C++17 Vulkan game engine
Fork of AbuseSDL to carry on development
Opensource crossplatform Fallout 2 game engine writen in C++ and SDL
Cross-platform port of Arx Fatalis, a first-person role-playing game
a UCI chess engine
Android apps.
Procedurally-Generated Game-Like Gym-Environments
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Vivid is a modern C++ 3D engine using OpenGL4+
DOOM / Heretic / Hexen source port with enhanced graphics and UI
Quake PAK file utility
3D C++ Game Engine - yet another open source game engine