improve determinism by inserting by entity order

Author: cscorley

src/plugin/systems.rs

@@ -719,6 +719,12 @@ pub fn init_colliders(
     let context = &mut *context;
     let physics_scale = context.physics_scale;
 
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut colliders: Vec<ColliderComponents> = colliders.iter().collect();
+        colliders.sort_by_key(|f| f.0);
+    }
+
     for (
         entity,
         shape,
@@ -836,6 +842,12 @@ pub fn init_rigid_bodies(
 ) {
     let physics_scale = context.physics_scale;
 
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut rigid_bodies: Vec<RigidBodyComponents> = rigid_bodies.iter().collect();
+        rigid_bodies.sort_by_key(|f| f.0);
+    }
+
     for (
         entity,
         rb,
@@ -979,6 +991,12 @@ pub fn init_joints(
     let context = &mut *context;
     let scale = context.physics_scale;
 
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut impulse_joints: Vec<(Entity, &ImpulseJoint)> = impulse_joints.iter().collect();
+        impulse_joints.sort_by_key(|f| f.0);
+    }
+
     for (entity, joint) in impulse_joints.iter() {
         let mut target = None;
         let mut body_entity = entity;
@@ -1003,6 +1021,13 @@ pub fn init_joints(
         }
     }
 
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut multibody_joints: Vec<(Entity, &MultibodyJoint)> =
+            multibody_joints.iter().collect();
+        multibody_joints.sort_by_key(|f| f.0);
+    }
+
     for (entity, joint) in multibody_joints.iter() {
         let target = context.entity2body.get(&entity);
 
@@ -1081,6 +1106,12 @@ pub fn sync_removals(
     /*
      * Collider removal detection.
      */
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut removed_colliders: Vec<Entity> = removed_colliders.iter().collect();
+        removed_colliders.sort();
+    }
+
     for entity in removed_colliders.iter() {
         if let Some(handle) = context.entity2collider.remove(&entity) {
             context
@@ -1090,6 +1121,12 @@ pub fn sync_removals(
         }
     }
 
+    #[cfg(feature = "enhanced-determinism")]
+    {
+        let mut orphan_colliders: Vec<Entity> = orphan_colliders.iter().collect();
+        orphan_colliders.sort();
+    }
+
     for entity in orphan_colliders.iter() {
         if let Some(handle) = context.entity2collider.remove(&entity) {
             context