Reduce some graphics memory usage by disabling unnecesary modes, closes #12831

editor/editor_node.cpp

@@ -269,6 +269,7 @@ void EditorNode::_notification(int p_what) {
 
 		Engine::get_singleton()->set_editor_hint(true);
 
+		get_tree()->get_root()->set_usage(Viewport::USAGE_2D_NO_SAMPLING); //reduce memory usage
 		get_tree()->get_root()->set_disable_3d(true);
 		get_tree()->get_root()->set_as_audio_listener(false);
 		get_tree()->get_root()->set_as_audio_listener_2d(false);
@@ -5021,6 +5022,7 @@ EditorNode::EditorNode() {
 	scene_root_parent->set_v_size_flags(Control::SIZE_EXPAND_FILL);
 
 	scene_root = memnew(Viewport);
+	scene_root->set_usage(Viewport::USAGE_2D);
 	scene_root->set_disable_3d(true);
 
 	VisualServer::get_singleton()->viewport_set_hide_scenario(scene_root->get_viewport_rid(), true);