bevy/crates/bevy_ecs/src/system.rs
Carter Anderson 196bde64e3 cargo fmt
2020-07-16 17:23:50 -07:00

147 lines
4.5 KiB
Rust

use crate::{Resources, World};
use fixedbitset::FixedBitSet;
use hecs::{Access, Query};
use std::{any::TypeId, borrow::Cow, collections::HashSet};
#[derive(Copy, Clone)]
pub enum ThreadLocalExecution {
Immediate,
NextFlush,
}
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct SystemId(pub u32);
impl SystemId {
pub fn new() -> Self {
SystemId(rand::random::<u32>())
}
}
pub trait System: Send + Sync {
fn name(&self) -> Cow<'static, str>;
fn id(&self) -> SystemId;
fn update_archetype_access(&mut self, world: &World);
fn archetype_access(&self) -> &ArchetypeAccess;
fn resource_access(&self) -> &TypeAccess;
fn thread_local_execution(&self) -> ThreadLocalExecution;
fn run(&mut self, world: &World, resources: &Resources);
fn run_thread_local(&mut self, world: &mut World, resources: &mut Resources);
fn initialize(&mut self, _resources: &mut Resources) {}
}
// credit to Ratysz from the Yaks codebase
#[derive(Default)]
pub struct ArchetypeAccess {
pub immutable: FixedBitSet,
pub mutable: FixedBitSet,
}
impl ArchetypeAccess {
pub fn is_compatible(&self, other: &ArchetypeAccess) -> bool {
self.mutable.is_disjoint(&other.mutable)
&& self.mutable.is_disjoint(&other.immutable)
&& self.immutable.is_disjoint(&other.mutable)
}
pub fn union(&mut self, other: &ArchetypeAccess) {
self.mutable.union_with(&other.mutable);
self.immutable.union_with(&other.immutable);
}
pub fn set_access_for_query<Q>(&mut self, world: &World)
where
Q: Query,
{
let iterator = world.archetypes();
let bits = iterator.len();
self.immutable.grow(bits);
self.mutable.grow(bits);
iterator
.enumerate()
.filter_map(|(index, archetype)| archetype.access::<Q>().map(|access| (index, access)))
.for_each(|(archetype, access)| match access {
Access::Read => self.immutable.set(archetype, true),
Access::Write => self.mutable.set(archetype, true),
Access::Iterate => (),
});
}
pub fn clear(&mut self) {
self.immutable.clear();
self.mutable.clear();
}
}
#[derive(Debug, Default, Eq, PartialEq, Clone)]
pub struct TypeAccess {
pub immutable: HashSet<TypeId>,
pub mutable: HashSet<TypeId>,
}
impl TypeAccess {
pub fn is_compatible(&self, other: &TypeAccess) -> bool {
self.mutable.is_disjoint(&other.mutable)
&& self.mutable.is_disjoint(&other.immutable)
&& self.immutable.is_disjoint(&other.mutable)
}
pub fn union(&mut self, other: &TypeAccess) {
self.mutable.extend(&other.mutable);
self.immutable.extend(&other.immutable);
}
pub fn clear(&mut self) {
self.immutable.clear();
self.mutable.clear();
}
}
#[cfg(test)]
mod tests {
use super::{ArchetypeAccess, TypeAccess};
use crate::{FetchResource, Res, ResMut, ResourceQuery};
use hecs::World;
use std::any::TypeId;
struct A;
struct B;
struct C;
#[test]
fn query_archetype_access() {
let mut world = World::default();
let e1 = world.spawn((A,));
let e2 = world.spawn((A, B));
let e3 = world.spawn((A, B, C));
let mut access = ArchetypeAccess::default();
access.set_access_for_query::<(&A,)>(&world);
let e1_archetype = world.get_entity_location(e1).unwrap().archetype as usize;
let e2_archetype = world.get_entity_location(e2).unwrap().archetype as usize;
let e3_archetype = world.get_entity_location(e3).unwrap().archetype as usize;
assert!(access.immutable.contains(e1_archetype));
assert!(access.immutable.contains(e2_archetype));
assert!(access.immutable.contains(e3_archetype));
let mut access = ArchetypeAccess::default();
access.set_access_for_query::<(&A, &B)>(&world);
assert!(access.immutable.contains(e1_archetype) == false);
assert!(access.immutable.contains(e2_archetype));
assert!(access.immutable.contains(e3_archetype));
}
#[test]
fn resource_query_access() {
let access =
<<(Res<A>, ResMut<B>, Res<C>) as ResourceQuery>::Fetch as FetchResource>::access();
let mut expected_access = TypeAccess::default();
expected_access.immutable.insert(TypeId::of::<A>());
expected_access.immutable.insert(TypeId::of::<C>());
expected_access.mutable.insert(TypeId::of::<B>());
assert_eq!(access, expected_access);
}
}