Trait specs::world::Component

source · [−]

pub trait Component: Any + Sized {
    type Storage: UnprotectedStorage<Self> + Any + Send + Sync;
}

Expand description

Abstract component type. Doesn’t have to be Copy or even Clone.

Storages

Components are stored in separated collections for maximum cache efficiency. The Storage associated type allows to specify which collection should be used. Depending on how many entities have this component and how often it is accessed, you will want different storages.

The most common ones are VecStorage (use if almost every entity has that component), DenseVecStorage (if you expect many entities to have the component) and HashMapStorage (for very rare components).

Examples

use specs::prelude::*;

pub struct Position {
    pub x: f32,
    pub y: f32,
}

impl Component for Position {
    type Storage = VecStorage<Self>;
}

use specs::prelude::*;

pub enum Light {
    // (Variants would have additional data)
    Directional,
    SpotLight,
}

impl Component for Light {
    type Storage = DenseVecStorage<Self>;
}

use specs::{prelude::*, storage::HashMapStorage};

pub struct Camera {
    // In an ECS, the camera would not itself have a position;
    // you would just attach a `Position` component to the same
    // entity.
    matrix: [f32; 16],
}

impl Component for Camera {
    type Storage = HashMapStorage<Self>;
}