Handles and Validity

Handles are opaque identities, not pointers or Jolt BodyID values. Generations prevent a destroyed handle from silently addressing a newly allocated object in the same slot. Resource type and world ownership must also match.

if (!is_undefined(body) && body.is_valid()) {
    if (!body.set_friction(0.5)) {
        var err = jolt_get_error();
        show_debug_message(err.message);
    }
}