Make cloning rigid-bodies and colliders more idiomatic.

Fix #53

2 files changed, 11 insertions, 12 deletions

diff --git a/src/geometry/collider.rs b/src/geometry/collider.rs
index f53d75a..524f265 100644
--- a/src/geometry/collider.rs
+++ b/src/geometry/collider.rs
@@ -188,6 +188,7 @@ impl<'de> serde::Deserialize<'de> for ColliderShape {
 }
 
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+#[derive(Clone)]
 /// A geometric entity that can be attached to a body so it can be affected by contacts and proximity queries.
 ///
 /// To build a new collider, use the `ColliderBuilder` structure.
@@ -212,20 +213,14 @@ pub struct Collider {
     pub user_data: u128,
 }
 
-impl Clone for Collider {
-    fn clone(&self) -> Self {
-        Self {
-            shape: self.shape.clone(),
-            parent: RigidBodySet::invalid_handle(),
-            contact_graph_index: ColliderGraphIndex::new(crate::INVALID_U32),
-            proximity_graph_index: ColliderGraphIndex::new(crate::INVALID_U32),
-            proxy_index: crate::INVALID_USIZE,
-            ..*self
-        }
+impl Collider {
+    pub(crate) fn reset_internal_links(&mut self) {
+        self.parent = RigidBodySet::invalid_handle();
+        self.contact_graph_index = ColliderGraphIndex::new(crate::INVALID_U32);
+        self.proximity_graph_index = ColliderGraphIndex::new(crate::INVALID_U32);
+        self.proxy_index = crate::INVALID_USIZE;
     }
-}
 
-impl Collider {
     /// The rigid body this collider is attached to.
     pub fn parent(&self) -> RigidBodyHandle {
         self.parent
diff --git a/src/geometry/collider_set.rs b/src/geometry/collider_set.rs
index 5ac9658..d2bb8cc 100644
--- a/src/geometry/collider_set.rs
+++ b/src/geometry/collider_set.rs
@@ -59,6 +59,10 @@ impl ColliderSet {
         parent_handle: RigidBodyHandle,
         bodies: &mut RigidBodySet,
     ) -> ColliderHandle {
+        // Make sure the internal links are reset, they may not be
+        // if this rigid-body was obtained by cloning another one.
+        coll.reset_internal_links();
+
         coll.parent = parent_handle;
         let parent = bodies
             .get_mut_internal(parent_handle)