Add an editor_description property to Node for documentation purposes

It is implemented using editor-only metadata, in a way similar to
edit locking or Position2D gizmo extents.

This closes #2082.

doc/classes/GraphNode.xml

@@ -174,6 +174,7 @@
 	</methods>
 	<members>
 		<member name="comment" type="bool" setter="set_comment" getter="is_comment" default="false">
+			If [code]true[/code], the GraphNode is a comment node.
 		</member>
 		<member name="offset" type="Vector2" setter="set_offset" getter="get_offset" default="Vector2( 0, 0 )">
 			The offset of the GraphNode, relative to the scroll offset of the [GraphEdit].

editor/scene_tree_editor.cpp

@@ -299,16 +299,34 @@ bool SceneTreeEditor::_add_nodes(Node *p_node, TreeItem *p_parent) {
 
 	if (p_node == get_scene_node() && p_node->get_scene_inherited_state().is_valid()) {
 		item->add_button(0, get_icon("InstanceOptions", "EditorIcons"), BUTTON_SUBSCENE, false, TTR("Open in Editor"));
-		item->set_tooltip(0, TTR("Inherits:") + " " + p_node->get_scene_inherited_state()->get_path() + "\n" + TTR("Type:") + " " + p_node->get_class());
-	} else if (p_node != get_scene_node() && p_node->get_filename() != "" && can_open_instance) {
 
+		String tooltip = TTR("Inherits:") + " " + p_node->get_scene_inherited_state()->get_path() + "\n" + TTR("Type:") + " " + p_node->get_class();
+		if (p_node->get_editor_description() != String()) {
+			tooltip += "\n\n" + p_node->get_editor_description();
+		}
+
+		item->set_tooltip(0, tooltip);
+	} else if (p_node != get_scene_node() && p_node->get_filename() != "" && can_open_instance) {
 		item->add_button(0, get_icon("InstanceOptions", "EditorIcons"), BUTTON_SUBSCENE, false, TTR("Open in Editor"));
-		item->set_tooltip(0, TTR("Instance:") + " " + p_node->get_filename() + "\n" + TTR("Type:") + " " + p_node->get_class());
+
+		String tooltip = TTR("Instance:") + " " + p_node->get_filename() + "\n" + TTR("Type:") + " " + p_node->get_class();
+		if (p_node->get_editor_description() != String()) {
+			tooltip += "\n\n" + p_node->get_editor_description();
+		}
+
+		item->set_tooltip(0, tooltip);
 	} else {
 		StringName type = EditorNode::get_singleton()->get_object_custom_type_name(p_node);
-		if (type == StringName())
+		if (type == StringName()) {
 			type = p_node->get_class();
-		item->set_tooltip(0, String(p_node->get_name()) + "\n" + TTR("Type:") + " " + type);
+		}
+
+		String tooltip = TTR("Type:") + " " + type;
+		if (p_node->get_editor_description() != String()) {
+			tooltip += "\n\n" + p_node->get_editor_description();
+		}
+
+		item->set_tooltip(0, tooltip);
 	}
 
 	if (can_open_instance && undo_redo) { //Show buttons only when necessary(SceneTreeDock) to avoid crashes

scene/main/node.cpp

@@ -1875,6 +1875,19 @@ String Node::get_filename() const {
 	return data.filename;
 }
 
+void Node::set_editor_description(const String &p_editor_description) {
+
+	set_meta("_editor_description_", p_editor_description);
+}
+String Node::get_editor_description() const {
+
+	if (has_meta("_editor_description_")) {
+		return get_meta("_editor_description_");
+	} else {
+		return "";
+	}
+}
+
 void Node::set_editable_instance(Node *p_node, bool p_editable) {
 
 	ERR_FAIL_NULL(p_node);
@@ -2788,6 +2801,10 @@ void Node::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("rpc_config", "method", "mode"), &Node::rpc_config);
 	ClassDB::bind_method(D_METHOD("rset_config", "property", "mode"), &Node::rset_config);
 
+	ClassDB::bind_method(D_METHOD("_set_editor_description", "editor_description"), &Node::set_editor_description);
+	ClassDB::bind_method(D_METHOD("_get_editor_description"), &Node::get_editor_description);
+	ADD_PROPERTY(PropertyInfo(Variant::STRING, "editor_description", PROPERTY_HINT_MULTILINE_TEXT, "", PROPERTY_USAGE_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_editor_description", "_get_editor_description");
+
 	ClassDB::bind_method(D_METHOD("_set_import_path", "import_path"), &Node::set_import_path);
 	ClassDB::bind_method(D_METHOD("_get_import_path"), &Node::get_import_path);
 	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "_import_path", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NOEDITOR | PROPERTY_USAGE_INTERNAL), "_set_import_path", "_get_import_path");
@@ -2860,10 +2877,6 @@ void Node::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("tree_exiting"));
 	ADD_SIGNAL(MethodInfo("tree_exited"));
 
-	//ADD_PROPERTY( PropertyInfo( Variant::BOOL, "process/process" ),"set_process","is_processing") ;
-	//ADD_PROPERTY( PropertyInfo( Variant::BOOL, "process/physics_process" ), "set_physics_process","is_physics_processing") ;
-	//ADD_PROPERTY( PropertyInfo( Variant::BOOL, "process/input" ), "set_process_input","is_processing_input" ) ;
-	//ADD_PROPERTY( PropertyInfo( Variant::BOOL, "process/unhandled_input" ), "set_process_unhandled_input","is_processing_unhandled_input" ) ;
 	ADD_GROUP("Pause", "pause_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "pause_mode", PROPERTY_HINT_ENUM, "Inherit,Stop,Process"), "set_pause_mode", "get_pause_mode");
 
@@ -2887,9 +2900,6 @@ void Node::_bind_methods() {
 	BIND_VMETHOD(MethodInfo("_unhandled_input", PropertyInfo(Variant::OBJECT, "event", PROPERTY_HINT_RESOURCE_TYPE, "InputEvent")));
 	BIND_VMETHOD(MethodInfo("_unhandled_key_input", PropertyInfo(Variant::OBJECT, "event", PROPERTY_HINT_RESOURCE_TYPE, "InputEventKey")));
 	BIND_VMETHOD(MethodInfo(Variant::STRING, "_get_configuration_warning"));
-
-	//ClassDB::bind_method(D_METHOD("get_child",&Node::get_child,PH("index")));
-	//ClassDB::bind_method(D_METHOD("get_node",&Node::get_node,PH("path")));
 }
 
 String Node::_get_name_num_separator() {

scene/main/node.h

@@ -318,6 +318,9 @@ public:
 	void set_filename(const String &p_filename);
 	String get_filename() const;
 
+	void set_editor_description(const String &p_editor_description);
+	String get_editor_description() const;
+
 	void set_editable_instance(Node *p_node, bool p_editable);
 	bool is_editable_instance(const Node *p_node) const;
 	void set_editable_instances(const HashMap<NodePath, int> &p_editable_instances);
@@ -363,8 +366,6 @@ public:
 	Node *duplicate_from_editor(Map<const Node *, Node *> &r_duplimap) const;
 #endif
 
-	//Node *clone_tree() const;
-
 	// used by editors, to save what has changed only
 	void set_scene_instance_state(const Ref<SceneState> &p_state);
 	Ref<SceneState> get_scene_instance_state() const;