RigidBodyControl cloning bug

rami · September 18, 2019, 8:23am

When cloning a spatial that has a RigidBodyControl the cloneFields method in the RigidBodyControl will clone the spatial but the new clone user object field will be null.

github.com

jMonkeyEngine/jmonkeyengine/blob/master/jme3-bullet/src/common/java/com/jme3/bullet/control/RigidBodyControl.java#L186


 * Callback from {@link com.jme3.util.clone.Cloner} to convert this
 * shallow-cloned control into a deep-cloned one, using the specified cloner
 * and original to resolve copied fields.
 *
 * @param cloner the cloner that's cloning this control (not null)
 * @param original the control from which this control was shallow-cloned
 * (unused)
 */
@Override   
public void cloneFields( Cloner cloner, Object original ) { 
    this.spatial = cloner.clone(spatial);
}
     
/**
 * Alter which spatial is controlled. Invoked when the control is added to
 * or removed from a spatial. Should be invoked only by a subclass or from
 * Spatial. Do not invoke directly from user code.
 *
 * @param spatial the spatial to control (or null)
 */
@Override

When the PhysicsCollisionObject collied with another object its user object will be null so the spatial reference that should be in the user object field will not be accessible from the collision listener. I think that there should be a setUserObject(spatial); in the cloneFields method.

sgold · September 18, 2019, 5:00pm

I believe this is an example of issue 797.

rami · September 18, 2019, 5:59pm

I suggested to set the user object in the RigidBodyControl cloneFields method so that the PhysicsRigidBody will not be affected and therefore KinimaticRagdollControl. This is an expected behaviour since the RigidBodyControl sets the spatial as the user object everywhere else.

sgold · September 18, 2019, 7:42pm

Thank you for your suggestion. I believe it would work.