Getting Started

You need a recent Rust toolchain (edition 2024) and this repository cloned somewhere.

cargo run -p kooch_editor

That opens the Hub, where projects are created and opened. Everything else follows from there:

• Your First Project — the whole loop end to end: a component, a system, and Play. Start here.
• Creating a Project — what the scaffold generates and why each file exists.
• The Editor — the panels, how Play works, and what is not built yet.

The rest of this page is the handful of things that are easy to trip over and do not belong to any one of those.

Loading a scene

The boot scene is resolved in this order:

1. SceneBootstrapPlugin::with_scene(path), if your main.rs sets one explicitly.
2. --scene <path> on the command line — absolute, or relative to the working directory.
3. scenes/default.scene, relative to the working directory.

So cargo run -- --game from the project root just works: the default path resolves because the working directory is the project. A different level is cargo run -- --game --scene scenes/Level1.scene.

Component registration runs before the scene loads

SceneBootstrapPlugin loads at Stage::First, which runs after every Stage::Startup system has completed on the first frame. Component registration is a Startup system, so the registry is fully populated by the time the scene is deserialised.

Flip that order and you get unknown component type: … and a scene that does not load. The generated registrations.rs already puts registration in Startup; this matters only if you register something by hand.

A scene with no camera renders black

The editor’s own camera is filtered out of a saved scene, so a scene needs to spawn its own PerspectiveCamera. The default scene template includes one. Build a scene from scratch without one and you get the clear-to-black fallback.

This is deliberate, not a bug. Injecting the editor camera as a temporary play camera — what Unity and Unreal do — is a possible future change, not current behaviour.

Running without the editor

cargo run -- --game

DefaultPlugins is the group that makes this a game rather than a collection of crates:

Your project’s own main.rs is what runs, so any plugin you add there is picked up.