Nano-ECS

A bare-bones macro-based Entity-Component-System

• Maximum 64 components per entity
• Stores components sequentially in same array
• Masks for enabled/disabled components

use nano_ecs::*;

#[derive(Clone)]
pub struct Position(pub f32);
#[derive(Clone)]
pub struct Velocity(pub f32);

ecs!{4: Position, Velocity}

fn main() {
    let mut world = World::new();
    world.push(Position(0.0));
    world.push((Position(0.0), Velocity(0.0)));
    let dt = 1.0;
    system!(world, |pos: &mut Position, vel: &Velocity| {
        pos.0 = pos.0 + vel.0 * dt;
    });
}

Design

The ecs! macro generates a World and Component object.

Can be used with any Rust data structure that implements Clone.

The order of declared components is used to assign every component an index. This index is used in the mask per entity and to handle slice memory correctly.

• All components are stored in one array inside World.
• All entities have a slice refering to components
• All entities have a mask that enable/disable components