context reinit support

core/glvertexobject.cpp

@@ -55,6 +55,15 @@ void VertexObject::destroy(QOpenGLExtraFunctions * f) {
 }
 
 
+void VertexObject::reinit() {
+	vao_ = 0;
+	buffer_obj.reinit();
+	buffer_sel.reinit();
+	buffers_binded = false;
+	objects_changed = selected_changed = true;
+}
+
+
 void VertexObject::bind(QOpenGLExtraFunctions * f) {
 	//qDebug() << "bind" << target_ << buffer_;
 	f->glBindVertexArray(vao_);