CollisionPipeline updates collider when parent body changes

src/pipeline/collision_pipeline.rs

@@ -7,6 +7,7 @@ use crate::geometry::{
 };
 use crate::math::Real;
 use crate::pipeline::{EventHandler, PhysicsHooks};
+use crate::prelude::{ModifiedRigidBodies, RigidBodyChanges};
 use crate::{dynamics::RigidBodySet, geometry::ColliderSet};
 
 /// The collision pipeline, responsible for performing collision detection between colliders.
@@ -114,6 +115,18 @@ impl CollisionPipeline {
         modified_colliders.clear();
     }
 
+    fn clear_modified_bodies(
+        &mut self,
+        bodies: &mut RigidBodySet,
+        modified_bodies: &mut ModifiedRigidBodies,
+    ) {
+        for handle in modified_bodies.iter() {
+            if let Some(rb) = bodies.get_mut_internal(*handle) {
+                rb.changes = RigidBodyChanges::empty();
+            }
+        }
+    }
+
     /// Executes one step of the collision detection.
     pub fn step(
         &mut self,
@@ -125,7 +138,7 @@ impl CollisionPipeline {
         hooks: &dyn PhysicsHooks,
         events: &dyn EventHandler,
     ) {
-        let modified_bodies = bodies.take_modified();
+        let mut modified_bodies = bodies.take_modified();
         let mut modified_colliders = colliders.take_modified();
         let mut removed_colliders = colliders.take_removed();
 
@@ -166,6 +179,7 @@ impl CollisionPipeline {
         );
 
         self.clear_modified_colliders(colliders, &mut modified_colliders);
+        self.clear_modified_bodies(bodies, &mut modified_bodies);
         removed_colliders.clear();
     }
 }
@@ -274,4 +288,54 @@ mod tests {
 
         assert!(hit, "No hit found");
     }
+
+    #[cfg(feature = "dim2")]
+    #[test]
+    fn test_collider_move_with_parent_body_updates_collisions() {
+        use na::{Isometry2, Rotation2, Translation2};
+
+        use crate::prelude::*;
+        let mut rigid_body_set = RigidBodySet::new();
+        let mut collider_set = ColliderSet::new();
+
+        let body = RigidBodyBuilder::fixed().build();
+        let body_handle = rigid_body_set.insert(body);
+
+        let collider = ColliderBuilder::ball(1.).build();
+        let collider_handle =
+            collider_set.insert_with_parent(collider, body_handle, &mut rigid_body_set);
+
+        let integration_parameters = IntegrationParameters::default();
+        let mut broad_phase = DefaultBroadPhase::new();
+        let mut narrow_phase = NarrowPhase::new();
+        let mut collision_pipeline = CollisionPipeline::default();
+
+        for i in 1..3 {
+            let next_position = Translation2::new(i as Real, 0.).vector;
+            rigid_body_set
+                .get_mut(body_handle)
+                .unwrap()
+                .set_translation(next_position, false);
+
+            collision_pipeline.step(
+                integration_parameters.prediction_distance(),
+                &mut broad_phase,
+                &mut narrow_phase,
+                &mut rigid_body_set,
+                &mut collider_set,
+                &(),
+                &(),
+            );
+
+            assert_eq!(
+                collider_set.get(collider_handle).unwrap().position(),
+                rigid_body_set.get(body_handle).unwrap().position(),
+                "Collider should be at the same position as the parent body after {i} step"
+            );
+            assert_eq!(
+                collider_set.get(collider_handle).unwrap().position(),
+                &Isometry2::new(next_position, Rotation2::identity().angle())
+            );
+        }
+    }
 }