Bevy vs Usagi Engine

Bevy is a free, open-source game engine built in Rust for 2D and 3D games, visualizations, interfaces, and other graphical applications. It uses a custom Entity Component System, with components represented as Rust structs and systems as Rust functions. The engine includes 2D and 3D rendering, a composable render graph, skeletal and morph-target animation, scene loading, hot reloading, UI, and audio playback. Its 2D renderer supports sprites, texture atlases, cameras, materials, custom shaders, and render pipelines. The 3D renderer includes lights, shadows, meshes, materials, cameras, and glTF loading. The ECS-driven UI framework uses flex-box layout and can be composed in code or scenes. Scene changes can update running applications; hot reloading currently covers scenes, textures, and meshes. Bevy targets Windows, macOS, Linux, web, iOS, and Android, and is available through crates.io with cargo add bevy. Users choose MIT or Apache 2.0 licensing, with no license fees or sales cuts. It remains in development, with possible missing features, sparse documentation, and breaking API changes about every three months.

Usagi Engine has no write-up on Specifiction yet; its figures are above.