From 23ca1befad3e48d7e48f11a3b02eebeed3c99e08 Mon Sep 17 00:00:00 2001
From: Joona Aalto <jondolf.dev@gmail.com>
Date: Mon, 12 Feb 2024 20:29:42 +0200
Subject: [PATCH] Fix colliders without `RigidBody` not working (#323)

# Objective

On the main branch, collisions between colliders without a `RigidBody` component are currently not detected. This is because some queries are overly strict and require components that only rigid bodies have.

## Solution

Make some components in queries optional in order to fix non-rigidbody colliders.
---
 src/plugins/collision/broad_phase.rs | 13 +++++++------
 src/plugins/sync.rs                  | 11 ++++++++---
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/plugins/collision/broad_phase.rs b/src/plugins/collision/broad_phase.rs
index d1676f4b..49761d0c 100644
--- a/src/plugins/collision/broad_phase.rs
+++ b/src/plugins/collision/broad_phase.rs
@@ -185,7 +185,7 @@ impl MapEntities for AabbIntervals {
 fn update_aabb_intervals(
     aabbs: Query<(
         &ColliderAabb,
-        &ColliderParent,
+        Option<&ColliderParent>,
         Option<&CollisionLayers>,
         Ref<Position>,
         Ref<Rotation>,
@@ -199,10 +199,11 @@ fn update_aabb_intervals(
                 aabbs.get(*collider_entity)
             {
                 *aabb = *new_aabb;
-                *collider_parent = *new_parent;
+                *collider_parent = new_parent.map_or(ColliderParent(*collider_entity), |p| *p);
                 *layers = new_layers.map_or(CollisionLayers::default(), |layers| *layers);
 
-                let is_static = rbs.get(new_parent.get()).is_ok_and(RigidBody::is_static);
+                let is_static =
+                    new_parent.is_some_and(|p| rbs.get(p.get()).is_ok_and(RigidBody::is_static));
                 *is_inactive = is_static || (!position.is_changed() && !rotation.is_changed());
 
                 true
@@ -219,7 +220,7 @@ fn add_new_aabb_intervals(
     aabbs: Query<
         (
             Entity,
-            &ColliderParent,
+            Option<&ColliderParent>,
             &ColliderAabb,
             Option<&RigidBody>,
             Option<&CollisionLayers>,
@@ -231,7 +232,7 @@ fn add_new_aabb_intervals(
     let aabbs = aabbs.iter().map(|(ent, parent, aabb, rb, layers)| {
         (
             ent,
-            *parent,
+            parent.map_or(ColliderParent(ent), |p| *p),
             *aabb,
             // Default to treating collider as immovable/static for filtering unnecessary collision checks
             layers.map_or(CollisionLayers::default(), |layers| *layers),
@@ -295,7 +296,7 @@ fn sweep_and_prune(
 /// Sorts a list iteratively using comparisons. In an ascending sort order, when a smaller value is encountered, it is moved lower in the list until it is larger than the item before it.
 ///
 /// This is relatively slow for large lists, but very efficient in cases where the list is already mostly sorted.
-fn insertion_sort<T>(items: &mut Vec<T>, comparison: fn(&T, &T) -> bool) {
+fn insertion_sort<T>(items: &mut [T], comparison: fn(&T, &T) -> bool) {
     for i in 1..items.len() {
         let mut j = i;
         while j > 0 && comparison(&items[j - 1], &items[j]) {
diff --git a/src/plugins/sync.rs b/src/plugins/sync.rs
index fd99579f..4d71ea1a 100644
--- a/src/plugins/sync.rs
+++ b/src/plugins/sync.rs
@@ -410,8 +410,8 @@ fn transform_to_position(
         &mut Position,
         Option<&AccumulatedTranslation>,
         &mut Rotation,
-        &PreviousRotation,
-        &CenterOfMass,
+        Option<&PreviousRotation>,
+        Option<&CenterOfMass>,
     )>,
 ) {
     for (
@@ -433,7 +433,12 @@ fn transform_to_position(
         let previous_transform = previous_transform.compute_transform();
         let pos = position.0
             + accumulated_translation.map_or(Vector::ZERO, |t| {
-                get_pos_translation(t, previous_rotation, &rotation, center_of_mass)
+                get_pos_translation(
+                    t,
+                    &previous_rotation.copied().unwrap_or_default(),
+                    &rotation,
+                    &center_of_mass.copied().unwrap_or_default(),
+                )
             });
 
         #[cfg(feature = "2d")]