Open Source C++ Game Engines
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C++ Game Engines
View 36 business solutionsBrowse free open source C++ Game Engines and projects below. Use the toggles on the left to filter open source C++ Game Engines by OS, license, language, programming language, and project status.
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Source Engine
Modified source engine (2017) developed by valve and leaked in 2020
The Source Engine repository under that particular GitHub user appears to be a custom (or forked) version of a game engine — likely an engine derived from or inspired by the classic Source engine lineage (or at least the name evokes that lineage). However, publicly-available documentation, community support or clarity about the project’s scope and maturity seems limited: the repo does not clearly advertise a full engine release or wide adoption. As such, it feels more like an experimental or hobby project: potentially a work-in-progress engine or engine-in-progress reimplementation rather than a full production-ready game engine. For a developer, this means you're likely to face missing features, limited tooling, and the need to fill gaps yourself, but also that you have a chance to influence or shape the architecture as you develop. -
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Unreal Engine 4/5 Scripting System
Injectable LUA scripting system, SDK generator, live property editor
Lua scripting system platform, C++ Modding API, SDK generator, blueprint mod loader, live property editor and other dumping utilities for UE4/5 games. The goal of UE4SS is not to be a plug-n-play solution that always works with every game. The goal is to have an underlying system that works for most games. -
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3D game engine (more powerful redesign of the Cube engine) and FPS game
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A game engine for running Ultima7 on modern operating systems, plus a map-editor and other tools for creating your own mods and games.
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Luanti
Voxel game-creation platform with easy modding and game creation
Luanti, originally known as Minetest, is a free, open-source voxel game engine and platform designed to let players, modders, and developers build and play diverse sandbox-style 3D worlds. Written in C++ for core performance and Lua for scripting, Luanti runs on multiple operating systems (Windows, macOS, Linux, BSD variants and even Android), making it highly accessible and cross-platform. Rather than being a single game, Luanti is meant as an engine and toolkit: individual “games” are actually collections of mods — written in Lua — that define terrain, items, NPCs, mechanics, and rules. This modular design enables rich customization and community-driven content: users can install new games, mods, and texture packs via a built-in content browser that draws from a central repository (ContentDB). Luanti supports both single-player and multiplayer via servers; players can host their own or join publicly listed ones, with server-side mods being applied automatically. -
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Multi Theft Auto: San Andreas
Multi Theft Auto is a game engine
Multi Theft Auto (MTA) is a software project that adds network play functionality to Rockstar North's Grand Theft Auto game series, in which this functionality is not originally found. It is a unique modification that incorporates an extendable network play element into a proprietary commercial single-player PC game. Multi Theft Auto is based on code injection and hooking techniques whereby the game is manipulated without altering any original files supplied with the game. The software functions as a game engine that installs itself as an extension of the original game, adding core functionality such as networking and GUI rendering while exposing the original game's engine functionality through a scripting language. Originally founded back in early 2003 as an experimental piece of C/C++ software, Multi Theft Auto has since grown into an advanced multiplayer platform for gamers and third-party developers. -
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Solar2D Game Engine
Solar2D Game Engine main repository (ex Corona SDK)
This is a fully open source project that is forked of the well-established and widely used Corona SDK game engine, which is no longer commercially supported. Development is lead by Vlad Shcherban, former technical lead engineer at Corona Labs Inc. If you are using this engine, consider supporting its development. Develop for mobile, desktop, and connected TV devices with just one code base: iOS, tvOS, Android, Android TV, macOS, Windows, Linux, or HTML5. Update your code, save the changes, and instantly see the results in our instant-update Simulator. When you're ready to test on real devices, build and deploy your app just once and then see code/assets update automatically, all over your local network. It's like magic. Select from numerous plugins which extend the Solar2D core for features like in-app advertising, analytics, media, and much more. A vast variety of plugins is available via Solar2D free directory or third party stores, like Solar2D Marketplace and Solar2D Plugins. -
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fheroes2
fheroes2 is a recreation of Heroes of Might and Magic II game engine
fheroes2 is a recreation of the Heroes of Might and Magic II game engine. This open-source multiplatform project, written from scratch, is designed to reproduce the original game with significant improvements in gameplay, graphics and logic (including support for high-resolution graphics, improved AI, numerous fixes and user interface improvements), breathing new life into one of the most addictive turn-based strategy games. You can find a complete list of all of our changes and enhancements in its own wiki page. -
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GemRB Game Engine
GemRB is a portable open-source implementation of the Infinity Engine
GemRB (Game engine made with pre-Rendered Background) is a portable open-source implementation of Bioware's Infinity Engine. It was written to support pseudo-3D role playing games based on the Dungeons & Dragons ruleset (Baldur's Gate and Icewind Dale series, Planescape: Torment). It should run on GNU/Linux, Microsoft Windows, OS X, possibly other UNIX derivatives and more. It is licensed under the GPL. -
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GDevelop
The game engine for everyone
GDevelop is an open-source, cross-platform game development software designed to make creating HTML5 and native games easy for everyone. Experts and novices alike can create their own games with GDevelop as it is fast and easy to learn, requiring no knowledge in a specific programming language. What makes GDevelop unique and so easy to use is its powerful and intuitive event-based system. Events are a powerful way to build up your game logic, without having to learn a programming language. GDevelop also features ready-made behaviors for your game objects, and allows you to create new behaviors through the easy to learn events. And when you're done, you can publish your game just about anywhere-- web, iOS, Android, Windows, Mac, Linux and even Facebook Messenger. Making games has never been easier or faster than with GDevelop! -
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Defold
Free game engine for development of desktop, mobile, and web games
Defold is an open-source, cross-platform game engine originally developed for 2D games but also capable of 3D — intended to give developers a turnkey solution for building games for desktop, mobile, web, and even consoles. It ships as a full editor/IDE, combining scene editing, asset management, scripting, and build/export pipelines, so developers don’t need to assemble disparate tools themselves. Game logic is written in Lua (with optional native extensions in C/C++ when needed), and the engine uses a component-based system and a message-passing paradigm to manage object interactions — a design that promotes loosely-coupled, reactive game code rather than traditional heavy OOP. Defold is optimized for efficiency: exported games tend to have small binary size and low memory use, making it appealing for mobile, HTML5/web, and lightweight games. -
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OpenXRay
Improved version of the X-Ray Engine, the game engine
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! OpenXRay is an 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. We want to keep the game as close as possible to the vanilla game, so instead of introducing new gameplay features, consider adding non-gameplay features, fixing bugs, improving performance and code quality. The dev branch is the default and base branch for the project. It is used for development and all Pull Requests should go there. But, be aware that this branch, sometimes, may be broken and, rarely, we can do force pushes to this branch. -
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Flax Engine
Flax Engine, multi-platform 3D game engine
The most agile game engine is now available. Full source code. Full power. Fully featured. Flax Engine is a high-quality modern 3D game engine written in C++ and C#. From stunning graphics to powerful scripts - Flax can give everything for your games. Designed for fast workflow with many ready-to-use features waiting for you right now. Flax Visual Studio extension provides better programming workflow, C# scripts debugging functionality, and allows to attach to running engine instance to debug C# source. Unleash your creativity and be more productive. With Flax you can boost your game development and bring it to another level. We’ve created tools that are slim and agile. No more lagging actions, long importing, or slow compilation. Everything you do as a developer with Flax is meant to be instant. Flax was built up with the idea of giving more power to the creators. Game development tools we create are making this goal possible. -
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3DWorld
3D Procedural Game Engine Using OpenGL
3DWorld is a cross-platform OpenGL-based 3D Game Engine that I've been working on since I took the CS184 computer graphics course at UC Berkeley in 2001. I converted the project from svn to git at commit 6607. Most of the code is written in C++, with GLSL for shaders. This is intended to be a cross-platform project. Microsoft Visual Studio 2019 and 2022 project files are included. A linux/gcc makefile is also included, but is more experimental. See README.linux for more details. The project should build under gcc on linux with some work, but it's been a while since I tried this. I have an old makefile that is out of date, but may not take too much work to fixup and make it usable. Realtime day/night cycle with weather (rain, snow, hail, wind, lightning). Physically based materials with reflection and refraction. Dynamic shadows, ambient occlusion, up to 1024 dynamic light sources, postprocessing effects. Built-in first person shooter game "smiley killer". -
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Panda3D
Powerful, mature open-source cross-platform game engine for Python
Powerful, mature open-source cross-platform game engine for Python and C++, developed by Disney and CMU. Panda3D is a game engine, a framework for 3D rendering and game development for Python and C++ programs. Panda3D is open-source and free for any purpose, including commercial ventures, thanks to its liberal license. To learn more about Panda3D's capabilities, visit the gallery and the feature list. To learn how to use Panda3D, check the documentation resources. If you get stuck, ask for help from our active community. You can build Panda3D with the Microsoft Visual C++ 2015, 2017, 2019 or 2022 compiler, which can be downloaded for free from the Visual Studio site. You will also need to install the Windows SDK, and if you intend to target Windows Vista, you will also need the Windows 8.1 SDK. -
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OpenRW
Recreation of the classic Grand Theft Auto III game executable
OpenRW is a cross-platform, open-source re-implementation of the game engine behind Grand Theft Auto III (GTA III). Its goal is to recreate the original gameplay engine in a modern, maintainable codebase so that GTA III can run natively on modern Windows, Linux, macOS, and BSD systems — long after the original executable becomes unworkable. The project does not ship with game content: users still need a legitimate copy of GTA III (with its original assets) to play, making OpenRW strictly an engine reimplementation, not a re-distribution. By re-writing the engine from scratch under a permissive, community-friendly license (GPLv3), OpenRW ensures long-term preservation, mod-friendliness, and better hardware compatibility (modern GPUs, controllers, cross-platform input, etc.). For developers, it also offers tools such as a “script tracer” to inspect in-game scripts opcode by opcode, a data-file viewer (RWViewer) for studying object data, models, and map files. -
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Doomsday Engine
DOOM / Heretic / Hexen source port with enhanced graphics and UI
A portable game engine for classic first person shooters such as DOOM, Heretic and Hexen. Lets you enjoy the original games using modern technology, including high-resolution OpenGL graphics, 3D models, and dynamic lighting effects. -
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VoxelCore
Voxel game engine in C++ with OpenGL
VoxelEngine-Cpp is a minimal voxel engine written in modern C++ using OpenGL, GLFW, and GLM, inspired by Minecraft-style block worlds. It offers a clean foundation for learning and experimenting with voxel-based rendering and world generation. With features like chunk loading, perlin noise terrain generation, and basic lighting, the engine is a perfect starting point for developers who want to create sandbox games or explore the technical aspects of 3D voxel environments. -
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Amazon Lumberyard
Amazon Lumberyard is a free AAA game engine
Amazon Lumberyard is (or was) a free AAA-capable game engine developed by AWS, with deep integration into AWS cloud services and the Twitch streaming platform. It provided full source access and offered developers tools to build high-quality games and simulations with networking, rendering, physics and cloud backend features built in. The engine allowed game creators to hook into AWS infrastructure for multiplayer services, analytics, voice chat, and more, and leveraged Twitch to build live-stream-enabled experiences. Although Amazon has since archived the repository and transitioned focus to the open-source successor Open 3D Engine (O3DE), the project remains of interest as a large-scale example of cloud-enabled game engine architecture. Developers studying game tech or infrastructure integration can inspect how the engine’s subsystems were designed, including entity/component architectures, rendering pipelines and networked game services. -
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dhewm 3
dhewm 3 main repository
dhewm3 is a source port of the original Doom3 (not Doom3 BFG, for that you may want to try RBDoom3BFG). It’s known to work on Windows, Linux, macOS, FreeBSD, OpenBSD and AROS, but it should work on (or be easily portable to) any system that supports OpenGL 1.4 with ARB shaders, SDL and OpenAL. Compared to the original version of Doom3, dhewm3 has many bugfixes, supports EAX-like sound effects on all operating systems and hardware (via OpenAL Softs EFX support), has much better support for widescreen resolutions and has 64bit support. It only supports old Mods if they either don’t require their own game DLL or have been ported to dhewm3. Note that while the Doom3 source code has been released under GPL, you still need to legally own the game and provide dhewm3 the game data to play. See the How to Install section for more information. -
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VCMI Project
Open-source engine for Heroes of Might and Magic III
VCMI is work-in-progress attempt to recreate engine for Heroes III, giving it new and extended possibilities. To use VCMI you need to own original data files. -
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PainTown
Paintown is a 2d fighting game engine.
Paintown is a 2d side scrolling beatem-up engine. Paintown supports game styles similar to the Sega Genesis game, Streets of Rage 2, as well as traditional 1 vs 1 fighting games through an implementation of MUGEN. Many aspects of Paintown are customizable, from the menu system to the levels and players that can be controlled. Paintown is highly portable. So far Paintown can run on Windows, OSX, Linux, BSD, Wii, PS3, Android and other systems. -
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Aleph One is the open source continuation of Bungie's Marathon 2 FPS game engine. Aleph One plays Marathon, Marathon 2, Marathon Infinity, and 3rd-party content on a wide array of platforms, with (optional) OpenGL rendering, Internet play, Lua scripting, and more.
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Spring RTS Engine
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Spring is a versatile 3D RTS game engine. Using extensively Lua for scripting game-specific code to make nearly every aspect of the engine customizable, from GUI, to unit AI, to pathfinding. -
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Thunder Engine
Cross-platform 2D and 3D game engine with modular architecture
Thunder is a lightweight, modular game engine written in C++ that provides a robust foundation for creating 2D and 3D games across platforms. It emphasizes a clean, component-based architecture and is designed for flexibility, performance, and scalability. Thunder includes built-in support for scripting, resource management, physics, animation, and rendering, with tools that facilitate efficient game development and deployment. Its cross-platform nature and minimal dependencies make it suitable for indie developers and small teams looking to build polished games with modern features.
