ferrous_app — Application Shell

ferrous_app is the top-level crate you depend on to build any FerrousEngine application. It wires together the window (winit), the GPU renderer, the GUI system, the asset server, and the ECS scheduler into a single coherent frame loop.

What lives here

Module / type	Role
App<T>	Fluent builder that accepts your FerrousApp impl and starts the event loop
AppBuilder	Plugin-based alternative builder (compose Plugin impls instead of a trait impl)
FerrousApp	Trait your application struct implements; six optional frame callbacks
AppContext<'_>	Per-frame handle passed to every callback — input, world, render, assets
RenderContext<'_>	User-facing renderer facade inside AppContext::render
AppConfig	Plain struct with all window / rendering configuration
Plugin trait	Extensibility mechanism; DefaultPlugins bundles all built-ins

Documentation map

docs/
├── README.md              ← this file
├── getting-started.md     ← step-by-step first app
├── app-builder.md         ← App<T> fluent API reference
├── plugins.md             ← AppBuilder + Plugin trait
├── ferrous-app-trait.md   ← FerrousApp callbacks
├── app-context.md         ← AppContext field & method reference
├── render-context.md      ← RenderContext method reference
└── config.md              ← ferrous.toml & AppConfig fields

Re-exported types

ferrous_app re-exports the most commonly needed primitives so you rarely need to add ferrous_core, ferrous_gui, or ferrous_renderer as direct dependencies:

// All usable as `ferrous_app::*`
pub use ferrous_core::{Color, Handle, InputState, KeyCode, MouseButton,
                       Time, Transform, World, Vec2, Vec3, Vec4, Quat, Mat4,
                       RenderStats, Viewport};
pub use ferrous_core::scene::{Camera3D, DirectionalLight, OrbitCamera,
                              Material, MaterialBuilder};
pub use ferrous_renderer::RenderStyle;
pub use ferrous_core::RenderQuality;
pub use ferrous_renderer::scene::GizmoDraw;
pub use ferrous_ecs::prelude::{Entity, StagedScheduler};