wecs

wecs (wckd-ecs) is a simple ECS library heavily based on bevy_ecs.

Motivation

As part of my "Road to Rust GameDev" journey, I wanted to learn how stuff worked behind the scenes, so I started with the foundation of many game engines, the Entity-Component-System. I did it by devouring bevy_ecs and creating my own version of it, with similar inner workings and identical syntax, without all the optimization that I am yet to learn. I'll be using it on my personal projects and hopefully be incrementing on its features.

Code Example

- "Gravity" sim

```rust use wecs::{query::Query, resource::Res, schedule::Schedule, world::World};

[derive(Resource, Default)]

pub struct GravityManager { gravity: f32, }

[derive(Debug, Component)]

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

fn main() { let mut world = World::new(); world.insertresource(GravityManager { gravity: 10.0 }); world.spawnentity(Position { x: 0.0, y: 50.0, z: 0.0, });

let mut schedule = Schedule::new()
    .with_system(update_system)
    .with_system(print_system);

loop {
    schedule.run(&mut world);
    std::thread::sleep(Duration::from_secs(1));
}

}

fn update_system(query: Query<&mut Position>, manager: Res) { for position in query { position.y -= manager.gravity; } }

fn print_system(query: Query<&Position>) { for position in query { let Position {x, y, z} = position; println!("entity position is {x},{y},{z}"); } } ```

output:

entity position is 0,40,0
entity position is 0,30,0
entity position is 0,20,0
entity position is 0,10,0
entity position is 0,0,0
entity position is 0,-10,0
entity position is 0,-20,0
...

- Events

```rust use wecs::{schedule::Schedule, world::World, EventManager, EventReader, EventWriter};

struct CoolEvent { pub num: u32, }

fn main() { let mut world = World::new(); world.init_resource::>();

let mut schedule = Schedule::new();
schedule.add_system(publish_events);
schedule.add_system(consume_events);
schedule.add_system(EventManager::<CoolEvent>::clear);

schedule.run(&mut world);

}

fn publishevents(mut writer: EventWriter) { writer.dispatchone(CoolEvent { num: 0 }); }

fn consume_events(reader: EventReader) { for event in reader { println!("CoolEvent's num is {}", event.num); } } ``` output:

CoolEvent's num is 0