Trait EntityMapper

Source

pub trait EntityMapper {
    // Required method
    fn map_entity(&mut self, entity: Entity) -> Entity;
}

Expand description

An implementor of this trait knows how to map an Entity into another Entity.

Usually this is done by using an EntityHashMap<Entity> to map source entities (mapper inputs) to the current world’s entities (mapper outputs).

More generally, this can be used to map Entity references between any two Worlds.

§Example

pub struct SimpleEntityMapper {
  map: EntityHashMap<Entity>,
}

// Example implementation of EntityMapper where we map an entity to another entity if it exists
// in the underlying `EntityHashMap`, otherwise we just return the original entity.
impl EntityMapper for SimpleEntityMapper {
    fn map_entity(&mut self, entity: Entity) -> Entity {
        self.map.get(&entity).copied().unwrap_or(entity)
    }
}