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
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.insert_resource(GravityManager { gravity: 10.0 });
world.spawn_entity(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<GravityManager>) {
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
use wecs::{schedule::Schedule, world::World, EventManager, EventReader, EventWriter};
struct CoolEvent {
pub num: u32,
}
fn main() {
let mut world = World::new();
world.init_resource::<EventManager<CoolEvent>>();
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 publish_events(mut writer: EventWriter<CoolEvent>) {
writer.dispatch_one(CoolEvent { num: 0 });
}
fn consume_events(reader: EventReader<CoolEvent>) {
for event in reader {
println!("CoolEvent's num is {}", event.num);
}
}
output:
CoolEvent's num is 0