Open-source alternatives to VPet

tModLoader is a modding framework and toolset designed for expanding game content and extending core game logic. It provides a polymorphic content API that allows for the creation of new items, NPCs, projectiles, and world assets through object-oriented inheritance. The project is distinguished by its advanced code modification capabilities, utilizing intermediate language bytecode patching and reflection-based private access to alter internal game behavior. It features a hot-reloading assembly runtime that enables developers to recompile and apply source code changes in real-time without res

Facepunch.Steamworks is a C# wrapper for the Steamworks API that connects .NET applications to the Steam platform. It enables the integration of core platform features such as user matchmaking and achievements. The library provides managed interfaces for Steam Cloud synchronization, allowing for the reading and writing of persistent user data. It also includes tools for Steam Workshop management to handle the publishing and downloading of community content, as well as Steam Inventory management for tracking digital assets and shop definitions. The implementation utilizes native interop and d

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

React Move is a declarative animation library for React that animates components by interpolating between start and end states with configurable timing and easing. It provides data-driven transitions for single elements, groups, lists, and SVG elements, supporting staggered timing, custom interpolation for non-numeric values like colors and paths, and drag-and-drop reordering of list items. The library distinguishes itself through its support for custom interpolation functions that replace default numeric interpolation, keyed array reconciliation for tracking items as they enter, update, or l

Skia is a high-performance 2D graphics rendering library used for drawing text, geometries, and images on digital surfaces. It functions as a hardware-accelerated graphics engine that offloads drawing operations to the GPU, a vector graphics processor for SVG and complex paths, and a typography engine for shaping and drawing characters with Unicode support. The project provides a cross-platform image codec for encoding and decoding standard image formats into raw pixel data across multiple operating systems. It also enables the development of user interfaces that maintain visual consistency a

Pixi.js is a high-performance 2D graphics engine used to render interactive animations, sprites, and visual effects in web browsers. It functions as a WebGL 2D rendering engine and HTML5 graphics library designed to produce high-performance two-dimensional visuals. The project operates as a 2D sprite framework and a web-based visual effects engine, providing tools to apply filters, blend modes, and masks to real-time graphics. It also serves as an interactive web canvas API for handling multi-touch and mouse input to build responsive graphical user interfaces. The framework covers a broad se

react-native-skia is a cross-platform graphics framework that provides a high-performance 2D graphics engine for rendering shapes, paths, and images. It functions as a vector graphics engine and UI animation toolkit, allowing for hardware-accelerated visuals across mobile and web platforms. The project is distinguished by its integration of the Skia 2D graphics library, enabling a shader and filter pipeline for complex pixel-level effects. It supports the rendering of Lottie animations exported from After Effects and the execution of animations directly on the UI thread to maintain fluid moti

Raycast Extensions is an open-source platform for building and distributing self-contained plugins that integrate with the Raycast desktop application. It provides an extension plugin framework where developers create packages using TypeScript, React, and Node.js, with each extension declaring its commands and permissions through a static manifest. The platform includes a hot-reload development server that watches source files and triggers live UI updates without restarting the host application. The platform distinguishes itself through deep AI integration capabilities, allowing extensions to

Mate-Engine is a 3D desktop avatar engine designed to render interactive characters that float on the desktop and react to system events. It functions as a virtual assistant platform, combining an interactive character renderer with an interface that connects local language models to 3D avatars for desktop conversations. The engine features a custom 3D model loader that imports third-party humanoid models using standard rigging and bone naming conventions. It includes an audio-reactive animation system that monitors live audio output from applications to automatically trigger dance sequences

NanoVG is a hardware-accelerated 2D drawing engine and C graphics primitive library. It provides a lightweight renderer designed for high-quality antialiased vector graphics using an OpenGL backend. The engine specializes in the construction and rendering of complex geometric paths. It supports the definition of precise shapes using lines, beziers, and arcs, with integrated winding rules to create hollow areas and composite shapes. The library covers a broad range of vector graphics capabilities, including path composition and the rendering of antialiased shapes. These tools enable the devel

This application is a high-performance media player designed for desktop environments, providing a unified interface for managing audio and video playback across local files and remote network streams. It supports a wide range of file formats and streaming protocols, utilizing native system frameworks and hardware-accelerated decoding to ensure synchronized, low-latency output. The player distinguishes itself through an extensible plugin architecture that allows for deep customization of the playback experience. Developers can build modular components to automate workflows, register custom co

BongoCat is a cross-platform desktop utility that provides real-time visual feedback for keyboard and mouse activity. It functions as an interactive companion that renders an animated character on the screen, which reacts dynamically to user inputs. The application operates entirely offline, ensuring that all input processing remains local to the user environment without external network dependencies or data collection. The software distinguishes itself through a flexible asset-based rendering system that allows users to import and apply custom character designs. By intercepting low-level inp

Airi is an interactive digital companion engine designed to bridge large language models with local animation rendering. It functions as a middleware platform that synchronizes conversational text streams with skeletal and facial movements to drive virtual avatars in real time. The framework distinguishes itself by integrating desktop context awareness, allowing characters to maintain situational awareness of a user's screen activity across both desktop and web environments. It utilizes a hybrid execution model that splits computational workloads between cloud-based language processing and lo

This project is a plugin-based WYSIWYG document layout engine and rich text editor that uses Canvas and SVG for rendering. It functions as a collaborative editor utilizing conflict-free replicated data types to enable real-time synchronization across multiple users. The system serves as an interactive form builder, allowing for the embedding of input controls such as checkboxes and date pickers directly into documents. It is designed for high-fidelity output, ensuring the visual representation during editing matches the final format for PDF and image exports. The editor covers broad capabili

cocos2d-objc is an Objective-C 2D game engine designed for developing interactive games and applications. It serves as a cross-platform game framework that enables the deployment of a shared codebase across iOS, tvOS, and macOS. The project features a hardware-accelerated 2D renderer utilizing OpenGL and Metal to display sprites, tile maps, and particle effects. It includes a dedicated OpenAL audio engine for managing music and spatialized sound effects, alongside a cross-platform input handler for processing touch, mouse, keyboard, and accelerometer events. The framework provides capabiliti

Tiptap is a headless rich text editor framework and extensible WYSIWYG framework designed for building custom text editors. It functions as a high-level wrapper around the ProseMirror toolkit, separating core editing logic and state management from the user interface. The framework enables real-time collaborative editing through a synchronization system using conflict-free replicated data types. It also supports the integration of AI content generation to provide automated suggestions and content refinement directly within the editor. The system utilizes a plugin-based extension architecture

Grid.js is a framework-agnostic JavaScript library for rendering interactive data grids. It allows for the display of structured information in tabular formats across different frontend environments, supporting data population from static arrays or JSON imports. The library features a plugin system for extending user interface components and logic, as well as a custom data pipeline for transforming information before it is displayed. It includes built-in support for multilingual localization to translate interface elements and messages. The project covers core data visualization capabilities

Slate is a customizable rich text editor framework that treats documents as a recursive tree of nodes. It functions as a schema-based, state-driven system designed to enforce structural constraints and manage nested components within a structured document model. The framework utilizes a plugin-based architecture to extend editor functionality, allowing for the injection of custom logic into the rendering and transformation pipeline. It supports real-time collaborative editing by synchronizing document operations across multiple users. The system covers a broad range of capabilities, includin

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

Buildbot is a Python-based continuous integration framework and distributed build orchestrator. It functions as a build automation engine that coordinates the retrieval of source code, the execution of build steps, and the reporting of results through a central controller and a network of remote worker agents. The system is distinguished by a plugin-based extensibility architecture and a master-worker distribution model. It allows for dynamic build modification at runtime and supports a pluggable database backend for persisting system state and historical build data. The project covers a bro

Funkin is a rhythm game engine and scriptable gameplay framework designed for creating musical battle games with synchronized note charts and audio. It functions as a comprehensive toolset for rhythm game modding, allowing for the addition of custom songs, characters, and stages through external assets and metadata. The project distinguishes itself through a dedicated modding system that supports priority-based asset overriding and a data patching utility for modifying JSON and XML configuration files via targeted merge operations. It utilizes a scriptable environment that executes external s

Opentui is a terminal user interface framework for building interactive command line applications. It provides a component-based system featuring a flexbox layout engine, a virtual node component tree, and a low-level 2D cell array renderer. The project is distinguished by a sophisticated keyboard binding engine that maps complex multi-stroke sequences and chords to named commands using prioritized, reactive layers. It also implements a plugin architecture that allows external modules to inject custom UI components into designated layout slots and extend input logic at runtime. Its capabilit

Embla Carousel is a lightweight JavaScript carousel library and barebones slider engine designed for creating touch-enabled, swipeable content sliders. It functions as a plugin-based framework that manages scroll physics and slide positioning without imposing specific UI styles, while providing a programmable API for custom carousel development. The system is distinguished by its modular architecture, allowing developers to extend core logic through external plugins and custom event hooks. It is compatible with server-side rendering, generating initial styles on the server to prevent layout s

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

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

Hilo is an HTML5 game engine for building 2D games that run across browsers and devices. It renders graphics through Canvas, DOM, or WebGL backends, automatically selecting the best option for the target environment. The engine provides a complete game development solution with sprite, skeletal, and particle animation, along with a texture atlas system for efficient image loading and rendering. The framework distinguishes itself through its integration of the DragonBones skeletal animation engine, which drives bone-based character movement without frame-by-frame sprites, and its Chipmunk phys

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