Open-source alternatives to UnityCsReference

Godot is a multi-platform game engine and a suite of tools used to develop 2D and 3D interactive games and applications across multiple operating systems. It provides specialized development environments for both two-dimensional and three-dimensional design, including tools for sprite animation, tilemaps, lighting, meshes, and physics simulations. The engine includes a cross-platform export tool that packages projects for deployment to desktop, mobile, web, and console hardware targets from a single codebase. The system covers broad capabilities for interactive experience design and game dev

Flecs is a high-performance entity component system framework and data-oriented programming library. It serves as a simulation engine core and game engine architecture tool, decoupling state from behavior by separating entities, components, and systems. The framework features a runtime reflection layer for dynamic data inspection and a built-in scripting system for defining entity behavior without recompilation. It also includes a network interface and REST API for remote simulation administration and state querying. The library covers a broad surface of simulation capabilities, including ar

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

Flame is a 2D game engine and framework for Flutter. It provides a component-based architecture to organize scene entities and manage their lifecycles through a structured hierarchy of game objects, coordinated by a consistent game loop. The engine includes a graphics library for rendering animated sprites, particle effects, and external textures. It features a 2D physics integration layer that supports rigid body dynamics and collision detection between entities. The framework covers additional capabilities for game engineering, including user input capture for gestures and gamepads, audio

Janet is a Lisp-based dynamic programming language featuring a register-based bytecode virtual machine and an embeddable scripting engine. It functions as a fiber-based concurrency runtime and includes a parsing engine based on Parsing Expression Grammars. The project is distinguished by its ability to be integrated into C or C++ applications via a minimal header interface. It utilizes a Lisp-style macro system for compile-time code transformation and employs prototype-based table inheritance for object-oriented behavior. The runtime covers a broad set of capabilities, including asynchronous

Mindustry is a cross-platform game engine and factory automation simulation that combines resource management with tower defense strategy. Players construct complex supply chains and automated networks to process materials while building defensive structures to protect a core from waves of hostile mechanical forces. The project utilizes a deterministic lockstep networking model to ensure simulation consistency across desktop and mobile devices. It is built on an entity-component-system architecture and a tile-based grid simulation, allowing for the efficient management of thousands of active

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

OpenDiablo2 is an open-source re-implementation of an isometric action role-playing game engine. It functions as a cross-platform game client designed to execute core mechanics and logic across multiple operating systems using external game assets. The project focuses on recreating the functionality of a classic action RPG from the ground up through a community-driven effort. It provides a framework for running a game engine that simulates specific gameplay experiences and movement patterns. The engine includes capabilities for isometric projection rendering, deterministic game state simulat

Halley is a modular C++ game engine designed for building cross-platform interactive applications. Its core identity is defined by a hardware-abstraction graphics pipeline for consistent rendering across different operating systems and an entity-component-system architecture that separates game state from processing logic. The framework features a hot-reloading development environment that allows updating application logic and assets at runtime without requiring a full process restart. It also includes a multiplayer networking framework based on an asynchronous messaging system to manage real

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

The Source Engine SDK is a C++ game development kit and modding framework designed for creating game modifications and custom gameplay extensions for the Source engine. It provides a structured environment and a collection of source code and binaries required to build custom content for compatible titles. The kit serves as a toolset for C++ game engine programming, enabling the development of custom gameplay mechanics, new rulesets, and game modes. It includes the libraries and headers necessary to compile and build gameplay extensions and custom game content.

Openage is an open-source game engine designed to execute real-time strategy games. It provides the core logic, networking, and rendering infrastructure necessary to recreate classic strategy mechanics across multiple operating systems. The engine utilizes a deterministic lockstep simulation and a client-server architecture to maintain synchronized game states across participants. It distinguishes itself through a data-driven configuration system that allows for extensive game modding, enabling users to adjust mechanics and visual elements by editing human-readable files without requiring sou

Space Station 14 is a C# multiplayer game and roleplay simulation framework. It is built upon an Entity-Component-System (ECS) game engine that separates logic into systems and data into components to manage complex entity interactions. The project functions as a grid-based physics simulator with a YAML data-driven prototype system for defining game objects. The project features a specialized 2D sprite rendering engine that maps server-side appearance data to client-side shaders. It implements a networking model with client-side prediction and dirty-flagged state synchronization to reduce inp

Ebiten is a cross-platform 2D game engine and framework for the Go programming language. It provides a hardware-accelerated 2D renderer and a multi-input handling library to develop two-dimensional games with a single codebase. The engine is designed for broad deployment, allowing applications to be compiled and run across desktops, mobile devices, web browsers, and gaming consoles. It distinguishes itself by integrating custom shader programming for specialized visual effects and providing haptic feedback control for mobile devices and gamepads. The framework covers core game development ca

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

MonoGame is a cross-platform game framework and C# game engine designed for the development of interactive software. It provides a unified environment for building games that run across desktop, mobile, and console platforms using a single codebase. The framework functions as a 2D graphics rendering library, offering tools to apply custom shaders and visual effects to game assets. It utilizes a graphics abstraction layer to map drawing commands to platform-specific APIs, ensuring consistent rendering across diverse hardware. The engine manages hardware-level tasks such as input handling, aud

The Android NDK samples provide a comprehensive collection of code examples demonstrating how to integrate C and C++ native code into Android applications. This repository serves as a practical guide for developers utilizing the Android Native Development Kit to implement performance-critical application components that require direct hardware access and low-level system interaction. The project highlights the use of the Java Native Interface to bridge managed code with native modules, enabling cross-language function calls and efficient data exchange. It demonstrates how to manage native act

JerryScript is a lightweight, ECMAScript-compliant JavaScript engine and bytecode compiler designed for resource-constrained devices. It serves as an embedded interpreter and IoT scripting runtime, enabling the execution of JavaScript code within native C applications on hardware with limited memory. The project differentiates itself through a focus on low-memory runtime management, utilizing bytecode precompilation and pre-compiled state snapshots to reduce startup time and memory overhead. It features a C-binding native bridge for bidirectional communication between native code and scripts,

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

s&box is a game development platform built on Valve's Source 2 engine, integrating the .NET runtime as a first-class scripting and gameplay logic layer. It provides a full-featured visual editor that combines asset management, level design, and code editing into a single workflow, enabling developers to create and edit games within a modern editor environment. The platform distinguishes itself through a managed-native interop bridge that allows C# code to interact directly with native Source 2 systems for high-performance communication, alongside a hot-reload scripting system that supports li

EnTT is a C++ library designed for data-oriented design and entity component system architecture. It provides a framework for managing game objects and simulation states by separating entity data from logic, allowing for the efficient organization and manipulation of large collections of related data objects. The library utilizes sparse sets to store entities and components in contiguous memory, which facilitates cache-friendly iteration and constant-time lookups. It employs template metaprogramming for compile-time type reflection and type-erasure techniques to provide a unified interface fo

FXGL is a 2D game engine and development framework designed for Java and Kotlin. It provides a structured environment for building cross-platform desktop games, integrating a central game loop with an entity component system and a JavaFX-based scene graph for rendering. The toolkit distinguishes itself by providing a comprehensive suite of integrated libraries for game AI pathfinding, physics collision resolution, and multiplayer networking via TCP and UDP protocols. It includes specialized systems for adaptive user interface design using global stylesheets and a data-driven asset management

GDevelop is a no-code game engine designed for building interactive 2D applications through a visual scripting environment. It allows users to define game logic and object interactions using a graphical interface of conditions and actions, eliminating the need for traditional programming. The platform functions as a cross-platform creator, enabling the export of projects to web, desktop, and mobile environments from a single codebase. The engine is built on a modular game development extension framework that supports the creation and sharing of reusable behaviors and logic components. Develop

shapez.io is an open-source automation base building game and infinite sandbox factory simulation. Players extract and process geometric shapes through conveyor belts and industrial automation to meet delivery goals within an endless map. The project incorporates a logic circuit simulation environment, allowing for the creation of automated control systems using wiring and logic gates to optimize factory operations. It utilizes an entity-component game architecture to manage thousands of active elements across its simulation. Gameplay covers industrial automation and resource logistics, spec

This repository is a comprehensive collection of functional 2D and 3D demo projects and implementation samples for the Godot Game Engine. It serves as an interactive tutorial and reference library, providing a working codebase to demonstrate how to apply engine features in real-world scenarios. The collection focuses on practical implementation guides, covering a wide array of technical capabilities from basic engine fundamentals to advanced rendering and scripting techniques. It allows users to study the application of node-based composition, asset pipelines, and game logic through direct ex

This project is a comprehensive educational resource and knowledge base designed to guide developers through the technical requirements of a career in game programming. It functions as a structured curriculum that organizes essential engineering principles and mathematical foundations into a logical roadmap, facilitating a clear progression from foundational concepts to advanced system mastery. The repository serves as a centralized hub for navigating the multidisciplinary domains of interactive software development. It provides curated references and learning materials across core areas incl

Pixel is a 2D game library and graphics engine for the Go programming language. It provides a hardware-accelerated renderer for drawing sprites, geometric shapes, and text, utilizing an optimized system of batching and transformation matrices. The project functions as a comprehensive toolkit for two-dimensional interactive applications, combining a graphics engine with a 2D vector math library for affine transformations and coordinate space projections. It includes a dedicated input manager that tracks keyboard presses and mouse movements using a polling-based system rather than asynchronous