diff options
Diffstat (limited to 'engine-ecs/src/component/storage/archetype.rs')
| -rw-r--r-- | engine-ecs/src/component/storage/archetype.rs | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/engine-ecs/src/component/storage/archetype.rs b/engine-ecs/src/component/storage/archetype.rs new file mode 100644 index 0000000..a7fe7ed --- /dev/null +++ b/engine-ecs/src/component/storage/archetype.rs @@ -0,0 +1,385 @@ +use std::any::Any; +use std::array::IntoIter as ArrayIntoIter; +use std::hash::{DefaultHasher, Hash, Hasher}; +use std::iter::{Enumerate, Filter, Map, RepeatN, Zip}; +use std::option::IntoIter as OptionIntoIter; +use std::slice::Iter as SliceIter; + +use hashbrown::HashMap; + +use crate::lock::Lock; +use crate::uid::{Kind as UidKind, Uid}; +use crate::util::{Either, HashMapExt}; + +#[derive(Debug)] +pub struct Archetype +{ + id: Id, + entities: Vec<Entity>, + entity_index_lookup: HashMap<Uid, usize>, + component_index_lookup: HashMap<Uid, usize>, + component_ids: Vec<Uid>, +} + +impl Archetype +{ + pub fn new(id: Id, component_ids: impl AsRef<[Uid]>) -> Self + { + Self { + id, + entities: Vec::new(), + entity_index_lookup: HashMap::new(), + component_index_lookup: component_ids + .as_ref() + .iter() + .enumerate() + .map(|(index, id)| (*id, index)) + .collect(), + component_ids: component_ids.as_ref().to_vec(), + } + } + + pub fn id(&self) -> Id + { + self.id + } + + pub fn is_superset(&self, other: &Self) -> bool + { + self.component_index_lookup + .keys_is_superset(&other.component_index_lookup) + } + + pub fn is_subset(&self, other: &Self) -> bool + { + self.component_index_lookup + .keys_is_subset(&other.component_index_lookup) + } + + pub fn get_entity_by_id(&self, entity_uid: Uid) -> Option<&Entity> + { + let index = *self.entity_index_lookup.get(&entity_uid)?; + + Some(self.entities.get(index).unwrap_or_else(|| { + panic!( + "In invalid state! Index of entity with ID {entity_uid:?} is out of bounds" + ); + })) + } + + pub fn push_entity(&mut self, entity: Entity) + { + self.entity_index_lookup + .insert(entity.uid, self.entities.len()); + + self.entities.push(entity); + } + + pub fn remove_entity(&mut self, entity_uid: Uid) -> Option<Entity> + { + //debug_assert_eq!(entity_uid.kind(), UidKind::Entity); + + let entity_index = self.entity_index_lookup.remove(&entity_uid)?; + + if self.entities.len() == 1 { + return Some(self.entities.remove(entity_index)); + } + + let last_entity_uid = self + .entities + .last() + .expect(concat!( + "Invalid state. No entities in archetype but entry was ", + "removed successfully from entity index lookup" + )) + .uid; + + // By using swap_remove, no memory reallocation occurs and only one index in the + // entity lookup needs to be updated + let removed_entity = self.entities.swap_remove(entity_index); + + self.entity_index_lookup + .insert(last_entity_uid, entity_index); + + Some(removed_entity) + } + + pub fn entities(&self) -> EntityIter<'_> + { + EntityIter { iter: self.entities.iter() } + } + + pub fn entity_cnt(&self) -> usize + { + self.entities.len() + } + + pub fn component_cnt(&self) -> usize + { + self.component_index_lookup.len() + } + + pub fn get_matching_component_indices( + &self, + component_id: Uid, + ) -> MatchingComponentIter<'_> + { + assert!( + component_id.kind() == UidKind::Component + || component_id.kind() == UidKind::Pair + ); + + if component_id.kind() == UidKind::Pair + && component_id.target_component() == Uid::wildcard() + { + return MatchingComponentIter { + inner: Either::A( + self.component_ids + .iter() + .enumerate() + .zip(std::iter::repeat_n(component_id, self.component_ids.len())) + .filter( + (|((_, other_comp_id), component_id)| { + other_comp_id.kind() == UidKind::Pair + && other_comp_id.has_same_relation_as(*component_id) + }) + as MatchingComponentIterFilterFn, + ) + .map(|((index, other_comp_id), _)| (*other_comp_id, index)), + ), + }; + } + + MatchingComponentIter { + inner: Either::B( + [component_id] + .into_iter() + .zip(self.get_index_for_component(component_id)), + ), + } + } + + pub fn get_index_for_component(&self, component_id: Uid) -> Option<usize> + { + assert!( + component_id.kind() == UidKind::Component + || (component_id.kind() == UidKind::Pair + && component_id.target_component() != Uid::wildcard()) + ); + + self.component_index_lookup.get(&component_id).copied() + } + + pub fn component_ids_unsorted(&self) -> impl Iterator<Item = Uid> + '_ + { + self.component_index_lookup.keys().copied() + } + + pub fn component_ids_sorted(&self) -> impl Iterator<Item = Uid> + '_ + { + self.component_ids.iter().copied() + } + + pub fn contains_matching_component(&self, component_id: Uid) -> bool + { + let component_id_kind = component_id.kind(); + + debug_assert!( + component_id_kind == UidKind::Component || component_id_kind == UidKind::Pair + ); + + if component_id.kind() == UidKind::Pair + && component_id.target_component() == Uid::wildcard() + { + return self.component_ids.iter().any(|other_comp_id| { + other_comp_id.kind() == UidKind::Pair + && other_comp_id.has_same_relation_as(component_id) + }); + } + + self.contains_component_with_exact_id(component_id) + } + + pub fn contains_component_with_exact_id(&self, component_id: Uid) -> bool + { + let component_id_kind = component_id.kind(); + + debug_assert!( + component_id_kind == UidKind::Component + || (component_id_kind == UidKind::Pair + && component_id.target_component() != Uid::wildcard()) + ); + + self.component_index_lookup.contains_key(&component_id) + } +} + +type MatchingComponentIterFilterFn = fn(&((usize, &Uid), Uid)) -> bool; + +type MatchingComponentIterMapFn = fn(((usize, &Uid), Uid)) -> (Uid, usize); + +type InnerMatchingComponentIterA<'archetype> = Map< + Filter< + Zip<Enumerate<SliceIter<'archetype, Uid>>, RepeatN<Uid>>, + MatchingComponentIterFilterFn, + >, + MatchingComponentIterMapFn, +>; + +type InnerMatchingComponentIterB = Zip<ArrayIntoIter<Uid, 1>, OptionIntoIter<usize>>; + +#[derive(Debug)] +pub struct MatchingComponentIter<'archetype> +{ + inner: Either<InnerMatchingComponentIterA<'archetype>, InnerMatchingComponentIterB>, +} + +impl Iterator for MatchingComponentIter<'_> +{ + type Item = (Uid, usize); + + fn next(&mut self) -> Option<Self::Item> + { + self.inner.next() + } +} + +#[derive(Debug)] +pub struct EntityIter<'archetype> +{ + iter: SliceIter<'archetype, Entity>, +} + +impl<'archetype> Iterator for EntityIter<'archetype> +{ + type Item = &'archetype Entity; + + fn next(&mut self) -> Option<Self::Item> + { + self.iter.next() + } +} + +#[derive(Debug)] +pub struct Entity +{ + uid: Uid, + components: Vec<EntityComponent>, +} + +impl Entity +{ + pub fn new(uid: Uid, components: impl IntoIterator<Item = EntityComponent>) -> Self + { + Self { + uid, + components: components.into_iter().collect(), + } + } + + pub fn uid(&self) -> Uid + { + self.uid + } + + pub fn components(&self) -> &[EntityComponent] + { + &self.components + } + + pub fn remove_component( + &mut self, + component_id: Uid, + archetype: &Archetype, + ) -> EntityComponent + { + let index = archetype + .get_index_for_component(component_id) + .expect("Archetype should contain component"); + + self.components.remove(index) + } + + pub fn insert_component( + &mut self, + component_id: Uid, + component: EntityComponent, + archetype: &Archetype, + ) + { + let index = archetype + .get_index_for_component(component_id) + .expect("Archetype should contain component"); + + self.components.insert(index, component); + } +} + +#[derive(Debug)] +pub struct EntityComponent +{ + component: Lock<Box<dyn Any>>, + name: &'static str, +} + +impl EntityComponent +{ + pub fn new(component: Box<dyn Any>, component_name: &'static str) -> Self + { + Self { + component: Lock::new(component, component_name), + name: component_name, + } + } + + pub fn component(&self) -> &Lock<Box<dyn Any>> + { + &self.component + } + + pub fn name(&self) -> &str + { + self.name + } +} + +/// Archetype ID. +#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)] +pub struct Id +{ + hash: u64, +} + +impl Id +{ + pub fn new_empty() -> Self + { + Self { hash: 0 } + } + + pub fn new<'a>(component_ids: impl IntoIterator<Item = &'a Uid>) -> Self + { + let mut hasher = DefaultHasher::new(); + + let mut prev_component_id: Option<Uid> = None; + + let mut component_id_iter = component_ids.into_iter().peekable(); + + if component_id_iter.peek().is_none() { + return Self::new_empty(); + } + + for comp_id in component_id_iter { + assert!( + prev_component_id.is_none_or(|prev_comp_id| *comp_id >= prev_comp_id), + "Cannot create archetype ID from a unsorted component metadata list" + ); + + prev_component_id = Some(*comp_id); + + comp_id.hash(&mut hasher); + } + + Self { hash: hasher.finish() } + } +} |