Derive Macro Catalog 

#[derive(Catalog)]
{
    // Attributes available to this derive:
    #[catalog]
}

Derives Catalog for a mesh vocabulary: every value the engine builds before the game’s startup closure runs, to prove the assets it names are loaded.

Fieldless variants catalog themselves. A variant with fields needs one #[catalog(...)] naming the values to prove, each written as a value of the type, and omitting it fails to compile: #[catalog(Self::Asteroid { seed: 1 }, Self::Asteroid { seed: 7 })]. Wrap a primitive in a variant’s field only when each of its values is its own mesh; a variant that draws one fixed primitive stays fieldless and builds it in build.