Crate entity_rust

Goal

We want to define components, store them in an efficient manner and make them accessible to systems.

We want to define events along with their types and make them available to systems.

We want to define systems that operate on lists of components, are triggered by other systems through events.

Implementation

For each component type there will be a list that is a tuple of an entity ID and the component values. There will also be a map from entity IDs to component list indexes.

A system will consist of state, iterators over components its subscribed to and any number of functions that are triggered by events.

Syntax

component! { Physics, body: physics.RigidBody, physics_id: physics.ID }

// event! { GameStarted } // This one is implicitly defined
event! { PhysicsTick, dt: u64 }
event! { Bump, e1: EntityID, e2: EntityID }

system! { PhysicsSystem,

  state! { world: physics.World }

  on! { GameStarted, {
     state.world = physics.World::new(event.name);
     state.world.on_collision = |e1, e2| {
       unwrap_entity = |e| { e.user_data.downcast_ref<EntityID>() }
       trigger! { Bump, unwrap_entity(e1), unwrap_entity(e2) }
     };
  }}

  on! { PhysicsTick, {
    state.world.step(event.dt);
  }}

  component_added! { Physics, {
    let id = state.world.add_body(component.body);
    component.physics_id = id;
  }}

  component_removed! { Physics, {
    state.world.remove_body(component.physics_id);
  }}

}

system! { BumpSystem, {
  on! { Bump, {
    println!("Entity {:?} bumped into entity {:?}!", e1, e2);
  }}
}}

Modules

components

entities

events

helpers

systems

tick

Macros

append_path_component

component

event

on

on_sync

state

static_any_vec_map

sync_event

system

Systems are a set of event handlers and optionally some associated state.

system_contents

system_register

Structs

Duration

A Duration type to represent a span of time, typically used for system timeouts.

Instant

A measurement of a monotonically nondecreasing clock. Opaque and useful only with Duration.

Functions

run

ticker