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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};
pub mod component;
#[derive(Debug)]
struct Entity
{
components: Vec<Box<dyn Component>>,
}
#[derive(Debug)]
pub struct World<Event>
{
systems: Vec<Box<dyn AnySystem>>,
events: HashMap<Event, Vec<usize>>,
extra: WorldExtra,
}
#[derive(Debug)]
struct WorldExtra
{
entities: Vec<Entity>,
}
impl<Event> World<Event>
{
#[must_use]
pub fn new() -> Self
{
Self {
systems: Vec::new(),
extra: WorldExtra { entities: Vec::new() },
events: HashMap::new(),
}
}
pub fn create_entity<Comps>(&mut self, components: Comps)
where
Comps: ComponentSequence,
{
self.extra
.entities
.push(Entity { components: components.into_vec() });
}
pub fn register_system<Comps>(&mut self, event: Event, system: System<Comps>)
where
Event: Hash + PartialEq + Eq,
Comps: ComponentSequence + 'static,
{
self.systems.push(Box::new(system));
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.call(&mut self.extra);
}
}
pub fn query<Comps>(&mut self) -> Query<Comps>
where
Comps: ComponentSequence,
{
Query::new(&mut self.extra)
}
}
impl<Event> Default for World<Event>
{
fn default() -> Self
{
Self::new()
}
}
pub type System<Comps> = fn(Query<Comps>);
trait AnySystem
{
fn call(&self, world: &mut WorldExtra);
}
impl<Comps> AnySystem for System<Comps>
where
Comps: ComponentSequence,
{
fn call(&self, world: &mut WorldExtra)
{
self(Query::new(world));
}
}
impl Debug for dyn AnySystem
{
fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
{
formatter.debug_struct("AnySystem").finish_non_exhaustive()
}
}
#[derive(Debug)]
pub struct Query<'world, Comps>
{
world: &'world mut WorldExtra,
comps_pd: PhantomData<Comps>,
}
impl<'world, Comps> Query<'world, Comps>
{
fn new(world: &'world mut WorldExtra) -> Self
{
Self { world, comps_pd: PhantomData }
}
}
impl<'world, Comps> Query<'world, Comps>
where
Comps: ComponentSequence,
{
pub fn iter_mut(&mut self) -> QueryComponentIter<Comps>
{
QueryComponentIter {
entity_iter: self.world.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))
}
}
|
