Track the change of effective dominance of a rigid-body.

4 files changed, 36 insertions, 6 deletions

diff --git a/src/dynamics/rigid_body.rs b/src/dynamics/rigid_body.rs
index c0acd5e..de11e15 100644
--- a/src/dynamics/rigid_body.rs
+++ b/src/dynamics/rigid_body.rs
@@ -331,7 +331,10 @@ impl RigidBody {
 
     /// The dominance group of this rigid-body.
     pub fn set_dominance_group(&mut self, dominance: i8) {
-        self.rb_dominance.0 = dominance
+        if self.rb_dominance.0 != dominance {
+            self.changes.insert(RigidBodyChanges::DOMINANCE);
+            self.rb_dominance.0 = dominance
+        }
     }
 
     /// Adds a collider to this rigid-body.
diff --git a/src/dynamics/rigid_body_components.rs b/src/dynamics/rigid_body_components.rs
index 82ecacf..a135a1c 100644
--- a/src/dynamics/rigid_body_components.rs
+++ b/src/dynamics/rigid_body_components.rs
@@ -107,6 +107,8 @@ bitflags::bitflags! {
         const COLLIDERS   = 1 << 3;
         /// Flag indicating that the `RigidBodyType` component of this rigid-body has been modified.
         const TYPE        = 1 << 4;
+        /// Flag indicating that the `RigidBodyDominance` component of this rigid-body has been modified.
+        const DOMINANCE   = 1 << 5;
     }
 }
 
diff --git a/src/geometry/collider_components.rs b/src/geometry/collider_components.rs
index 7d621f3..1c737dd 100644
--- a/src/geometry/collider_components.rs
+++ b/src/geometry/collider_components.rs
@@ -47,16 +47,21 @@ bitflags::bitflags! {
     pub struct ColliderChanges: u32 {
         /// Flag indicating that any component of the collider has been modified.
         const MODIFIED = 1 << 0;
-        /// Flag indicating that the `RigidBodyParent` component of the collider has been modified.
+        /// Flag indicating that the `ColliderParent` component of the collider has been modified.
         const PARENT   = 1 << 1; // => BF & NF updates.
-        /// Flag indicating that the `RigidBodyPosition` component of the collider has been modified.
+        /// Flag indicating that the `ColliderPosition` component of the collider has been modified.
         const POSITION = 1 << 2; // => BF & NF updates.
-        /// Flag indicating that the `RigidBodyGroups` component of the collider has been modified.
+        /// Flag indicating that the collision groups of the collider have been modified.
         const GROUPS   = 1 << 3; // => NF update.
-        /// Flag indicating that the `RigidBodyShape` component of the collider has been modified.
+        /// Flag indicating that the `ColliderShape` component of the collider has been modified.
         const SHAPE    = 1 << 4; // => BF & NF update. NF pair workspace invalidation.
-        /// Flag indicating that the `RigidBodyType` component of the collider has been modified.
+        /// Flag indicating that the `ColliderType` component of the collider has been modified.
         const TYPE     = 1 << 5; // => NF update. NF pair invalidation.
+        /// Flag indicating that the dominance groups of the parent of this collider have been modified.
+        ///
+        /// This flags is automatically set by the `PhysicsPipeline` when the `RigidBodyChanges::DOMINANCE`
+        /// or `RigidBodyChanges::TYPE` of the parent rigid-body of this collider is detected.
+        const PARENT_EFFECTIVE_DOMINANCE = 1 << 6; // NF update.
     }
 }
 
@@ -76,6 +81,11 @@ impl ColliderChanges {
 
     /// Do these changes justify a narrow-phase update?
     pub fn needs_narrow_phase_update(self) -> bool {
+        // NOTE: for simplicity of implementation, we return `true` even if
+        //       we only need a dominance update. If this does become a
+        //       bottleneck at some point in the future (which is very unlikely)
+        //       we could do a special-case for dominance-only change (so that
+        //       we only update the relative_dominance of the pre-existing contact.
         self.bits() > 1
     }
 }
diff --git a/src/pipeline/user_changes.rs b/src/pipeline/user_changes.rs
index 699361c..643360c 100644
--- a/src/pipeline/user_changes.rs
+++ b/src/pipeline/user_changes.rs
@@ -155,6 +155,21 @@ pub(crate) fn handle_user_changes_to_rigid_bodies<Bodies, Colliders>(
                 }
             }
 
+            if changes.contains(RigidBodyChanges::DOMINANCE)
+                || changes.contains(RigidBodyChanges::TYPE)
+            {
+                for handle in rb_colliders.0.iter() {
+                    colliders.map_mut_internal(handle.0, |co_changes: &mut ColliderChanges| {
+                        if !co_changes.contains(ColliderChanges::MODIFIED) {
+                            modified_colliders.push(*handle);
+                        }
+
+                        *co_changes |=
+                            ColliderChanges::MODIFIED | ColliderChanges::PARENT_EFFECTIVE_DOMINANCE;
+                    });
+                }
+            }
+
             bodies.set_internal(handle.0, RigidBodyChanges::empty());
             bodies.set_internal(handle.0, ids);
             bodies.set_internal(handle.0, activation);