Fix BroadPhase proxy handle recycling causing a crash.

examples3d/add_remove3.rs

@@ -0,0 +1,53 @@
+use na::Point3;
+use rapier3d::dynamics::{JointSet, RigidBodyBuilder, RigidBodySet};
+use rapier3d::geometry::{ColliderBuilder, ColliderSet};
+use rapier_testbed3d::Testbed;
+
+pub fn init_world(testbed: &mut Testbed) {
+    let bodies = RigidBodySet::new();
+    let colliders = ColliderSet::new();
+    let joints = JointSet::new();
+    let rad = 0.5;
+
+    // Callback that will be executed on the main loop to handle proximities.
+    testbed.add_callback(move |window, physics, _, graphics, _| {
+        let rigid_body = RigidBodyBuilder::new_dynamic()
+            .translation(0.0, 10.0, 0.0)
+            .build();
+        let handle = physics.bodies.insert(rigid_body);
+        let collider = ColliderBuilder::cuboid(rad, rad, rad).density(1.0).build();
+        physics
+            .colliders
+            .insert(collider, handle, &mut physics.bodies);
+        graphics.add(window, handle, &physics.bodies, &physics.colliders);
+
+        let to_remove: Vec<_> = physics
+            .bodies
+            .iter()
+            .filter(|(_, b)| b.position.translation.vector.y < -10.0)
+            .map(|e| e.0)
+            .collect();
+        for handle in to_remove {
+            physics.pipeline.remove_rigid_body(
+                handle,
+                &mut physics.broad_phase,
+                &mut physics.narrow_phase,
+                &mut physics.bodies,
+                &mut physics.colliders,
+                &mut physics.joints,
+            );
+            graphics.remove_body_nodes(window, handle);
+        }
+    });
+
+    /*
+     * Set up the testbed.
+     */
+    testbed.set_world(bodies, colliders, joints);
+    testbed.look_at(Point3::new(-30.0, -4.0, -30.0), Point3::new(0.0, 1.0, 0.0));
+}
+
+fn main() {
+    let testbed = Testbed::from_builders(0, vec![("Add-remove", init_world)]);
+    testbed.run()
+}