Entity Inspector

[LiamGallagher737]

A way to view the entity hierarchy and components would be very useful for a learning / experimenting tool like this.

How

I previously started working working on this but decided to focus on improving the current state of the playground rather than adding heaps of features. The work can be found on the entity-inspector branch.

This approach was to store a pointer to the Bevy world and have a get_entities method which could be called from js. The following is the extra Rust that would be added before compiling.

learnbevy/bevy_compile_api/src/config.rs

Lines 35 to 67 in adfc196

	static __WORLD_PTR: std::sync::OnceLock::<usize> = std::sync::OnceLock::new();
	#[wasm_bindgen::prelude::wasm_bindgen]
	pub unsafe fn __get_entities() -> wasm_bindgen::JsValue {
	let ptr_usize = __WORLD_PTR.get().unwrap();
	let ptr = *ptr_usize as *const bevy::ecs::world::World;
	let world = ptr.as_ref().unwrap();
	let map = js_sys::Map::new();
	for entity in world.iter_entities() {
	let id = entity.id();
	let components_info = world.inspect_entity(id);
	let len = components_info.len() as u32;
	let component_names = js_sys::Array::new_with_length(len);
	for n in 0..len {
	let js_name = wasm_bindgen::JsValue::from_str(components_info[n as usize].name());
	component_names.set(n, js_name);
	}
	map.set(&wasm_bindgen::JsValue::from_str(&format!("{id:?}")), &wasm_bindgen::JsValue::from(component_names));
	}
	wasm_bindgen::JsValue::from(map)
	}
	fn __set_world_ptr(world: &bevy::ecs::world::World) {
	let _ = __WORLD_PTR.set(world as *const bevy::ecs::world::World as usize);
	}
	#[derive(Debug)]
	#[wasm_bindgen::prelude::wasm_bindgen(getter_with_clone)]
	pub struct __EntityInfo {
	#[wasm_bindgen(readonly)]
	pub index: u32,
	#[wasm_bindgen(readonly)]
	pub generation: u32,
	#[wasm_bindgen(readonly)]
	pub component_names: wasm_bindgen::JsValue,
	}"#;

For accessing the components we would just use Bevy reflect in a similar way to how I get the entities in the code snippet above.

Visuals (thoughts wanted)

I am unsure of the best way to display the inspector / hierarchy in the playground. It should defiantly be toggleable to avoid taking space when not needed.