update

src/libslic3r/ObjectID.cpp

@@ -0,0 +1,24 @@
+#include "ObjectID.hpp"
+
+namespace Slic3r {
+
+size_t ObjectBase::s_last_id = 0;
+
+// Unique object / instance ID for the wipe tower.
+ObjectID wipe_tower_object_id()
+{
+    static ObjectBase mine;
+    return mine.id();
+}
+
+ObjectID wipe_tower_instance_id()
+{
+    static ObjectBase mine;
+    return mine.id();
+}
+
+ObjectWithTimestamp::Timestamp ObjectWithTimestamp::s_last_timestamp = 1;
+
+} // namespace Slic3r
+
+// CEREAL_REGISTER_TYPE(Slic3r::ObjectBase)