Open-source alternatives to Source Engine

This project is an open-source 3D game engine designed for building high-fidelity games, simulations, and cinematic environments. It functions as a robotics simulation platform with native integration for ROS 2 to model robot controllers and sensors. The engine features a multi-threaded Forward+ physically based renderer that supports hardware-accelerated ray tracing and global illumination. The system is built on a modular extension architecture using Gems to add or replace features without modifying core binaries. It includes a native SDK for AWS cloud integration, enabling IAM authenticati

This is the original C source code for the Quake game engine, a landmark first-person shooter engine from the 1990s. It is a retro game engine that renders 3D environments and processes player input in real time using CPU-based software rendering rather than GPU acceleration. The engine supports networked multiplayer gameplay over LAN or internet connections and is designed to be moddable, allowing users to create and run custom game modifications and levels. The engine's architecture includes a Binary Space Partition tree for efficient world geometry organization and visibility determination

Veloren is an open-source multiplayer RPG featuring a voxel-based action adventure in a procedurally generated fantasy world. It is built upon a voxel game engine that supports 3D rendering via Vulkan and Metal, utilizing a procedural world generator to create geography and ecosystems based on erosion algorithms and temperature maps. The project is distinguished by a sandboxed plugin system using WebAssembly, which allows for the addition of new game logic and equipment without recompiling the core engine. It also features a dedicated game server architecture designed to synchronize state, ma

Spring is a cross-platform game engine and framework designed specifically for the development and execution of multiplayer real-time strategy games. It provides a high-performance simulation environment for managing large-scale battles and unit movements across different operating systems using a shared codebase. The engine functions as a multiplayer game server and networking layer, coordinating real-time game state and match synchronization between remote players. It includes a dedicated lobby client system for multiplayer match coordination as well as the capability to execute single-play

The Forge is a low-level toolkit for building high-performance graphics engines and applications across desktop, mobile, and console platforms. It provides a cross-platform engine framework and a dedicated shader compiler that translates a single source into target-specific languages for various graphics APIs and hardware. The project includes a GPU memory and resource manager that utilizes unified root signatures for resource binding, alongside a ray tracing rendering pipeline that implements hardware-accelerated ray and path tracing queries. State management is handled through a high-perfor

This project is a cross-platform game engine framework and build pipeline designed to produce playable executable binaries for desktop and Android devices. It provides a collection of core libraries for game development, including a native Android build system and a C++ build pipeline. The framework features a specialized bitmap font rendering system that displays stylized typography by mapping character indices to image atlases using coordinate and spacing metadata. It also implements a hardware abstraction layer to decouple application logic from graphics and audio drivers, ensuring portabl

Cocos2d-x is a high-performance C++ game development framework designed for building and deploying interactive applications across mobile, desktop, and web platforms. It functions as a cross-platform game engine that utilizes an entity-component system to manage object lifecycles, behaviors, and spatial relationships within a unified codebase. The engine is distinguished by its specialized 2D graphics rendering pipeline, which is optimized for hardware-accelerated performance when displaying sprites, particle effects, and skeletal animations. It provides developers with low-level access to gr

Bevy is a cross-platform game engine and framework built in Rust, designed for creating interactive simulations and graphical applications. It utilizes a data-oriented entity-component-system architecture to manage game state, organizing data into contiguous memory blocks to facilitate high-performance processing and massive parallelization of entities. The engine distinguishes itself through a modular plugin architecture and a system-based task scheduler that automatically parallelizes logic by analyzing data access patterns. By employing reactive change detection and deferred command buffer

Fyrox is a Rust-based game engine for building both 2D and 3D games, designed as a native engine with no runtime dependencies. It compiles directly to native code for Windows, macOS, Linux, and WebAssembly, providing direct hardware access through the Rust programming language. The engine is built around an entity-component-system architecture that organizes game objects as entities with attached components processed by modular systems. Its graph-based scene management represents game scenes as directed acyclic graphs of nodes with transform hierarchies and property inheritance, while a paral

OpenMW is a modern, open-source game engine designed to execute the game Morrowind and its expansions. It serves as a cross-platform game runtime and 3D world renderer, providing a data-driven environment to run game logic and physics with improved stability. The project functions as a game modding framework, utilizing a modular plugin system and an interpreted scripting layer to load external modifications. This architecture allows for the integration of community content, custom textures, and external scripts without altering the base executable code. The engine covers a broad range of cap

Julius is a cross-platform game engine and simulation tool designed for the reimplementation of legacy games. It executes original game logic using the original assets while applying modern resolution and interface updates. The engine features a localization framework for integrating community translations of text, audio, and video, and an integrated scenario editor for configuring gameplay rules and resource requirements within map data files. The project covers a broad capability surface including save game management with automated backups, input mapping for diverse keyboard layouts and t

Piccolo is a mini game engine designed for building small-scale games with cross-platform support. It compiles and runs on Windows, macOS, and Linux from a unified codebase, and includes an editor integration for live editing and debugging. The engine uses a component-based entity system with data-oriented design, storing component data in contiguous arrays for cache-friendly iteration. It features a fixed timestep game loop that decouples simulation updates from rendering frame rate, and provides a physics debug overlay that renders visual shapes from simulation data synchronized with the ed

ggez is a 2D game framework for the Rust programming language. It provides a hardware abstraction layer for accessing keyboard, mouse, sound, and graphics hardware, alongside a dedicated game loop manager that synchronizes input processing, state updates, and frame rendering for real-time applications. The framework includes a hardware-accelerated rendering engine for drawing sprites, shapes, and text using shader programs. It also features a resource management system that uses a filesystem abstraction to load and manage game assets from physical directories or compressed archives. Addition

Cocos Engine is a cross-platform game engine designed for building high-performance 2D and 3D interactive experiences for web, mobile, and desktop platforms. It features a multi-backend rendering engine and a 2D and 3D physics simulator, utilizing a core architecture that combines a C++ runtime for performance with TypeScript for game logic scripting. The engine distinguishes itself through a multi-platform deployment system that packages projects for native operating systems and instant-play web ecosystems. Its graphics system supports multiple APIs, employing physically based rendering and

Craft is a multiplayer voxel sandbox written in C. It utilizes an OpenGL voxel engine to render a block-based world and implements an infinite terrain generator that uses noise functions to create deterministic, procedural landscapes. The project features a networked environment where players can build and modify a shared world using socket-based state synchronization. To maintain consistency across sessions, it employs a voxel world database to store and retrieve modified block coordinates. The system covers a range of capabilities including 3D collision detection for character movement, to

OpenTTD is an open-source game engine and transport simulation game. It provides an isometric sandbox environment for building and managing complex logistics and transport networks. The project functions as a multiplayer simulation sandbox where users can build infrastructure cooperatively or competitively in a shared virtual world. The platform is designed as a moddable simulation system that supports external assets, graphics, and gameplay modifications. It includes mechanisms for downloading and integrating add-on content and utilizes a plugin-based system to extend game mechanics beyond t

Echo is a cross-platform game engine designed for the development of two-dimensional and three-dimensional interactive projects. It provides a unified environment that integrates scene management, visual scripting, and graphics rendering into a single workflow, allowing developers to build and deploy applications across desktop, mobile, and web platforms. The engine distinguishes itself through a node-based architecture that governs both scene organization and game logic. By utilizing a visual scripting tool and a data-flow shader graph, users can define complex behaviors and custom materials

egret-core is a cross-platform game engine and mobile application framework used to develop 2D and 3D software for Android, iOS, and Windows. It serves as a multi-platform graphics engine and input handler designed to maintain consistent visual output and interaction behavior across different hardware. The project provides a game physics and animation suite that integrates external libraries for skeletal animations, particle systems, and complex physics simulations. It utilizes a hardware-abstraction layer to standardize touch, keyboard, and mouse interactions across multiple operating system

This project is a game server management panel and multi-user administration tool. It provides a centralized web interface and orchestrator for deploying, configuring, and monitoring game servers running inside isolated Docker containers. The system manages the full lifecycle of server instances, from mapping network allocations and IP addresses to enforcing resource limits through containerization. It includes a hosting dashboard for handling server backups via local or cloud storage and a control plane for remote-agent communication with server nodes. Administrative capabilities cover role

Quake-2 is a game engine designed for the development of first-person shooters and the rendering of three-dimensional environments. It provides the core framework for processing real-time physics and player input within interactive 3D spaces. The engine supports software extensibility, allowing for the direct modification of source code to change gameplay mechanics and engine behaviors. This makes it a resource for retro game engineering and the study of early 3D development techniques. Its technical capabilities include vertex-based software rendering, BSP-tree spatial partitioning, and PVS

This repository is a collection of reference implementations and sample projects demonstrating data-oriented design using the Unity Entities package. It provides a suite of examples for implementing an entity component system that separates game data into components and logic into systems. The collection includes specialized demonstrations for rendering large volumes of entities via graphics pipelines, implementing high-performance collision and rigid body dynamics through data-oriented physics, and managing multiplayer state synchronization using the network framework for entities. It also p

Amethyst is a data-driven game engine written in Rust for building high-performance 2D and 3D games. It is built on an entity component system architecture that decouples game state from logic to enable parallel processing and reusable code. The framework features a glTF 3D renderer for importing scenes and geometry using physically based materials. It also serves as a multiplayer game framework, providing network transport abstractions and state synchronization for real-time online experiences. The engine covers a broad range of capabilities, including hybrid 2D/3D rendering, asynchronous a

Ambient is a cross-platform multiplayer game engine and runtime environment developed in Rust. It provides a system for building and deploying high-performance games that run across web browsers and desktop platforms using WebAssembly and WebGPU. The project features a networked database that automatically replicates real-time state and components between servers and players. It utilizes WebAssembly sandboxes to isolate game logic, which prevents individual script crashes and allows for the secure execution of untrusted code. The framework includes a graphics system for high-fidelity 3D visu

Gameplay is a high-performance C++ game engine and cross-platform framework designed for developing 2D and 3D interactive games. It functions as both a 3D graphics engine for rendering environments and a 2D game development kit for creating sprite-based mechanics. The framework provides a cross-platform abstraction layer to ensure that game logic and graphics run across various hardware and software platforms using a shared codebase. The engine implements a hardware-accelerated rendering pipeline and component-based game logic to separate data from behavior. It utilizes a native C++ impleme

Murder is an entity component system game engine designed for 2D game development. It provides a core framework for managing game objects through an ECS architecture and includes a dedicated 2D game editor for asset management and real-time property configuration. The engine features a specialized 2D rendering pipeline supporting pixel art, sprite slicing, and parallax effects. It includes a hierarchical A* pathfinding system for agent navigation and a comprehensive asset management system for serializing and loading game resources. The project covers a broad range of capabilities, including

Flame is a 2D game engine for Flutter and Dart. It provides a component-based game framework for managing entities and their lifecycles through a hierarchical architecture, alongside a dedicated system for game asset management and input handling. The engine distinguishes itself through a specialized integration layer for external physics engines to handle rigid body dynamics and collision detection. It also features a high-performance task model that uses isolates to offload heavy computations and prevent main thread blocking. The framework covers a broad range of capabilities including vis