2D child Z grows without bounds

[Pierre-Borges]

I made an entity with a position that has a child which also has a position. Both of them have a nonzero z component for draw ordering. That caused the z component of the transform to go off like crazy.

I think this is caused by position_to_transform taking the z coordinate of the child's original transform and treating it as a global transform.

                let new_transform = GlobalTransform::from(
                    Transform::from_translation(pos.as_f32().extend(transform.translation.z))
                        .with_rotation(Quaternion::from(*rot).as_f32()),
                )
                .reparented_to(&GlobalTransform::from(parent_transform));

I changed this to

                let new_transform = GlobalTransform::from(
                    Transform::from_translation(pos.as_f32().extend(transform.translation.z + parent_transform.translation.z))
                        .with_rotation(Quaternion::from(*rot).as_f32()),
                )
                .reparented_to(&GlobalTransform::from(parent_transform));

but I don't know if that still works if the parent is scaled. Maybe it would be best to just set it after doing the GlobalTransform::from?