Implement batched query support

* Only Dense queries are accelerated currently
* Certain features are awaiting on GATs/generic const expressions
* Code refactored to use GATs
* `elain` crate now used to provide const generic alignments (PhantomData method)
* Code still requires a fixed alignment request across whole query (in progress)
* Batches support AsRef, AsMut, etc
* Simplified calling for_each_{mut_}batched (no longer need _ arguments)
* Add convenience functions for treating AlignedBatch16<f32, 4> as Vec4s
* Add a map API for creating projections of aligned batches
* Add a compile-time error in case a greater alignment is needed than the current batch alignment to satisfy T
* Documentation about SIMD and batching
* ALIGN now referred to as MIN_ALIGN for clarity

crates/bevy_ecs/Cargo.toml

@@ -30,6 +30,7 @@ serde = { version = "1", features = ["derive"] }
 
 [dev-dependencies]
 rand = "0.8"
+bevy_math = { path = "../bevy_math", version = "0.9.0-dev" }
 
 [[example]]
 name = "events"

crates/bevy_ecs/src/archetype.rs

@@ -5,7 +5,7 @@ use crate::{
     bundle::BundleId,
     component::{ComponentId, StorageType},
     entity::{Entity, EntityLocation},
-    storage::{SparseArray, SparseSet, SparseSetIndex, TableId},
+    storage::{aligned_vec::SimdAlignedVec, SparseArray, SparseSet, SparseSetIndex, TableId},
 };
 use std::{
     collections::HashMap,
@@ -181,7 +181,7 @@ pub struct Archetype {
     id: ArchetypeId,
     table_id: TableId,
     edges: Edges,
-    entities: Vec<ArchetypeEntity>,
+    entities: SimdAlignedVec<ArchetypeEntity>,
     table_components: Box<[ComponentId]>,
     sparse_set_components: Box<[ComponentId]>,
     components: SparseSet<ComponentId, ArchetypeComponentInfo>,
@@ -225,7 +225,7 @@ impl Archetype {
         Self {
             id,
             table_id,
-            entities: Vec::new(),
+            entities: SimdAlignedVec::new(),
             components,
             table_components,
             sparse_set_components,

crates/bevy_ecs/src/change_detection.rs

@@ -1,7 +1,15 @@
 //! Types that detect when their internal data mutate.
 
+use crate::ptr::{
+    batch::AlignedBatch,
+    elain::{Align, Alignment},
+};
+
 use crate::{component::ComponentTicks, ptr::PtrMut, system::Resource};
-use std::ops::{Deref, DerefMut};
+use std::{
+    marker::PhantomData,
+    ops::{Deref, DerefMut},
+};
 
 /// The (arbitrarily chosen) minimum number of world tick increments between `check_tick` scans.
 ///
@@ -229,6 +237,15 @@ pub(crate) struct Ticks<'a> {
     pub(crate) change_tick: u32,
 }
 
+pub(crate) struct TicksBatch<'a, const N: usize, const MIN_ALIGN: usize>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    pub(crate) component_ticks: &'a mut AlignedBatch<ComponentTicks, N, MIN_ALIGN>,
+    pub(crate) last_change_tick: u32,
+    pub(crate) change_tick: u32,
+}
+
 /// Unique mutable borrow of a [`Resource`].
 ///
 /// See the [`Resource`] documentation for usage.
@@ -352,6 +369,132 @@ change_detection_impl!(Mut<'a, T>, T,);
 impl_methods!(Mut<'a, T>, T,);
 impl_debug!(Mut<'a, T>,);
 
+/// Unique mutable borrow of an entity's component (batched version).
+/// Each batch changes in unison:  a batch has changed if any of its elements have changed.
+pub struct MutBatch<'a, T, const N: usize, const MIN_ALIGN: usize>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    pub(crate) value: &'a mut AlignedBatch<T, N, MIN_ALIGN>,
+    pub(crate) ticks: TicksBatch<'a, N, MIN_ALIGN>,
+    pub(crate) _marker: PhantomData<T>,
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> DetectChanges for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    #[inline]
+    fn is_added(&self) -> bool {
+        self.ticks
+            .component_ticks
+            .as_array()
+            .iter()
+            .any(|x| x.is_added(self.ticks.last_change_tick, self.ticks.change_tick))
+    }
+
+    #[inline]
+    fn is_changed(&self) -> bool {
+        self.ticks
+            .component_ticks
+            .as_array()
+            .iter()
+            .any(|x| x.is_changed(self.ticks.last_change_tick, self.ticks.change_tick))
+    }
+
+    #[inline]
+    fn set_changed(&mut self) {
+        for ticks in self.ticks.component_ticks.as_array_mut().iter_mut() {
+            ticks.set_changed(self.ticks.change_tick);
+        }
+    }
+
+    #[inline]
+    fn last_changed(&self) -> u32 {
+        self.ticks.last_change_tick
+    }
+
+    type Inner = AlignedBatch<T, N, MIN_ALIGN>;
+
+    fn set_last_changed(&mut self, last_change_tick: u32) {
+        self.ticks.last_change_tick = last_change_tick;
+    }
+
+    fn bypass_change_detection(&mut self) -> &mut Self::Inner {
+        self.value
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> Deref for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    type Target = AlignedBatch<T, N, MIN_ALIGN>;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.value
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> DerefMut for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    #[inline]
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.set_changed();
+        self.value
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> AsRef<AlignedBatch<T, N, MIN_ALIGN>>
+    for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    #[inline]
+    fn as_ref(&self) -> &AlignedBatch<T, N, MIN_ALIGN> {
+        self.deref()
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> AsMut<AlignedBatch<T, N, MIN_ALIGN>>
+    for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    #[inline]
+    fn as_mut(&mut self) -> &mut AlignedBatch<T, N, MIN_ALIGN> {
+        self.deref_mut()
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+{
+    /// Consume `self` and return a mutable reference to the
+    /// contained value while marking `self` as "changed".
+    #[inline]
+    pub fn into_inner(mut self) -> &'a mut AlignedBatch<T, N, MIN_ALIGN> {
+        self.set_changed();
+        self.value
+    }
+}
+
+impl<'a, T, const N: usize, const MIN_ALIGN: usize> std::fmt::Debug
+    for MutBatch<'a, T, N, MIN_ALIGN>
+where
+    Align<MIN_ALIGN>: Alignment,
+    AlignedBatch<T, N, MIN_ALIGN>: std::fmt::Debug,
+    T: std::fmt::Debug,
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple(stringify!($name)).field(&self.value).finish()
+    }
+}
+
 /// Unique mutable borrow of resources or an entity's component.
 ///
 /// Similar to [`Mut`], but not generic over the component type, instead