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#![deny(clippy::all, clippy::pedantic)]
use std::any::TypeId;
use std::collections::{HashMap, HashSet};
use std::fmt::Debug;
use std::hash::Hash;
use std::marker::PhantomData;
use std::slice::IterMut as SliceIterMut;
use crate::component::{Component, Sequence as ComponentSequence};
use crate::system::{System, TypeErased as TypeErasedSystem};
pub mod component;
pub mod system;
#[derive(Debug)]
struct Entity
{
components: Vec<Box<dyn Component>>,
}
#[derive(Debug)]
pub struct World<Event>
{
systems: Vec<TypeErasedSystem>,
events: HashMap<Event, Vec<usize>>,
component_storage: ComponentStorage,
}
impl<Event> World<Event>
{
#[must_use]
pub fn new() -> Self
{
Self {
systems: Vec::new(),
component_storage: ComponentStorage { entities: Vec::new() },
events: HashMap::new(),
}
}
pub fn create_entity<Comps>(&mut self, components: Comps)
where
Comps: ComponentSequence,
{
self.component_storage
.entities
.push(Entity { components: components.into_vec() });
}
pub fn register_system<TSystem, SystemImpl>(&mut self, event: Event, system: TSystem)
where
Event: Hash + PartialEq + Eq,
TSystem: System<SystemImpl>,
{
self.systems.push(system.into_type_erased());
self.events
.entry(event)
.or_default()
.push(self.systems.len() - 1);
}
/// Emits a event, running all systems listening to the event for each compatible
/// entity.
///
/// # Panics
/// Will panic if a system has dissapeared.
pub fn emit(&mut self, event: &Event)
where
Event: Hash + PartialEq + Eq,
{
let Some(system_indices) = self.events.get(event).cloned() else {
return;
};
for system_index in system_indices {
let system = self.systems.get_mut(system_index).unwrap();
system.run(&mut self.component_storage);
}
}
pub fn query<Comps>(&mut self) -> Query<Comps>
where
Comps: ComponentSequence,
{
Query::new(&mut self.component_storage)
}
}
impl<Event> Default for World<Event>
{
fn default() -> Self
{
Self::new()
}
}
#[derive(Debug)]
pub struct Query<'world, Comps>
{
component_storage: &'world mut ComponentStorage,
comps_pd: PhantomData<Comps>,
}
impl<'world, Comps> Query<'world, Comps>
{
fn new(component_storage: &'world mut ComponentStorage) -> Self
{
Self {
component_storage,
comps_pd: PhantomData,
}
}
}
impl<'world, Comps> Query<'world, Comps>
where
Comps: ComponentSequence,
{
pub fn iter_mut(&mut self) -> QueryComponentIter<Comps>
{
QueryComponentIter {
entity_iter: self.component_storage.entities.iter_mut(),
component_type_ids: Comps::type_ids(),
comps_pd: PhantomData,
}
}
}
pub struct QueryComponentIter<'world, Comps>
{
entity_iter: SliceIterMut<'world, Entity>,
component_type_ids: Vec<TypeId>,
comps_pd: PhantomData<Comps>,
}
impl<'world, Comps> Iterator for QueryComponentIter<'world, Comps>
where
Comps: ComponentSequence + 'world,
{
type Item = Comps::MutRefs<'world>;
fn next(&mut self) -> Option<Self::Item>
{
// TODO: This is a really dumb and slow way to do this. Refactor the world
// to store components in archetypes
let entity =
self.entity_iter.find(|entity| {
let entity_components: HashSet<_> = entity
.components
.iter()
.map(|component| component.as_ref().type_id())
.collect();
if self.component_type_ids.iter().all(|component_type_id| {
entity_components.contains(component_type_id)
}) {
return true;
}
false
})?;
Some(Comps::from_components(&mut entity.components))
}
}
#[derive(Debug)]
pub struct ComponentStorage
{
entities: Vec<Entity>,
}
|
