Unify determination of default property values

4 files changed, 280 insertions, 149 deletions

diff --git a/scene/property_utils.cpp b/scene/property_utils.cpp
new file mode 100644
index 0000000000..79821b8399
--- /dev/null
+++ b/scene/property_utils.cpp
@@ -0,0 +1,185 @@
+/*************************************************************************/
+/*  property_utils.cpp                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "property_utils.h"
+
+#include "core/config/engine.h"
+#include "core/templates/local_vector.h"
+#include "editor/editor_node.h"
+#include "scene/resources/packed_scene.h"
+
+bool PropertyUtils::is_property_value_different(const Variant &p_a, const Variant &p_b) {
+	if (p_a.get_type() == Variant::FLOAT && p_b.get_type() == Variant::FLOAT) {
+		//this must be done because, as some scenes save as text, there might be a tiny difference in floats due to numerical error
+		return !Math::is_equal_approx((float)p_a, (float)p_b);
+	} else {
+		// For our purposes, treating null object as NIL is the right thing to do
+		const Variant &a = p_a.get_type() == Variant::OBJECT && (Object *)p_a == nullptr ? Variant() : p_a;
+		const Variant &b = p_b.get_type() == Variant::OBJECT && (Object *)p_b == nullptr ? Variant() : p_b;
+		return a != b;
+	}
+}
+
+Variant PropertyUtils::get_property_default_value(const Object *p_object, const StringName &p_property, const Vector<SceneState::PackState> *p_states_stack_cache, bool p_update_exports, const Node *p_owner, bool *r_is_class_default) {
+	// This function obeys the way property values are set when an object is instantiated,
+	// which is the following (the latter wins):
+	// 1. Default value from builtin class
+	// 2. Default value from script exported variable (from the topmost script)
+	// 3. Value overrides from the instantiation/inheritance stack
+
+	if (r_is_class_default) {
+		*r_is_class_default = false;
+	}
+
+	Ref<Script> topmost_script;
+
+	if (const Node *node = Object::cast_to<Node>(p_object)) {
+		// Check inheritance/instantiation ancestors
+		const Vector<SceneState::PackState> &states_stack = p_states_stack_cache ? *p_states_stack_cache : PropertyUtils::get_node_states_stack(node, p_owner);
+		for (int i = 0; i < states_stack.size(); ++i) {
+			const SceneState::PackState &ia = states_stack[i];
+			bool found = false;
+			Variant value_in_ancestor = ia.state->get_property_value(ia.node, p_property, found);
+			if (found) {
+				return value_in_ancestor;
+			}
+			// Save script for later
+			bool has_script = false;
+			Variant script = ia.state->get_property_value(ia.node, SNAME("script"), has_script);
+			if (has_script) {
+				Ref<Script> scr = script;
+				if (scr.is_valid()) {
+					topmost_script = scr;
+				}
+			}
+		}
+	}
+
+	// Let's see what default is set by the topmost script having a default, if any
+	if (topmost_script.is_null()) {
+		topmost_script = p_object->get_script();
+	}
+	if (topmost_script.is_valid()) {
+		// Should be called in the editor only and not at runtime,
+		// otherwise it can cause problems because of missing instance state support
+		if (p_update_exports && Engine::get_singleton()->is_editor_hint()) {
+			topmost_script->update_exports();
+		}
+		Variant default_value;
+		if (topmost_script->get_property_default_value(p_property, default_value)) {
+			return default_value;
+		}
+	}
+
+	// Fall back to the default from the native class
+	if (r_is_class_default) {
+		*r_is_class_default = true;
+	}
+	return ClassDB::class_get_default_property_value(p_object->get_class_name(), p_property);
+}
+
+// Like SceneState::PackState, but using a raw pointer to avoid the cost of
+// updating the reference count during the internal work of the functions below
+namespace {
+struct _FastPackState {
+	SceneState *state = nullptr;
+	int node = -1;
+};
+} // namespace
+
+static bool _collect_inheritance_chain(const Ref<SceneState> &p_state, const NodePath &p_path, LocalVector<_FastPackState> &r_states_stack) {
+	bool found = false;
+
+	LocalVector<_FastPackState> inheritance_states;
+
+	Ref<SceneState> state = p_state;
+	while (state.is_valid()) {
+		int node = state->find_node_by_path(p_path);
+		if (node >= 0) {
+			// This one has state for this node
+			inheritance_states.push_back({ state.ptr(), node });
+			found = true;
+		}
+		state = state->get_base_scene_state();
+	}
+
+	for (int i = inheritance_states.size() - 1; i >= 0; --i) {
+		r_states_stack.push_back(inheritance_states[i]);
+	}
+
+	return found;
+}
+
+Vector<SceneState::PackState> PropertyUtils::get_node_states_stack(const Node *p_node, const Node *p_owner, bool *r_instantiated_by_owner) {
+	if (r_instantiated_by_owner) {
+		*r_instantiated_by_owner = true;
+	}
+
+	LocalVector<_FastPackState> states_stack;
+	{
+		const Node *owner = p_owner;
+#ifdef TOOLS_ENABLED
+		if (!p_owner && Engine::get_singleton()->is_editor_hint()) {
+			owner = EditorNode::get_singleton()->get_edited_scene();
+		}
+#endif
+
+		const Node *n = p_node;
+		while (n) {
+			if (n == owner) {
+				const Ref<SceneState> &state = n->get_scene_inherited_state();
+				if (_collect_inheritance_chain(state, n->get_path_to(p_node), states_stack)) {
+					if (r_instantiated_by_owner) {
+						*r_instantiated_by_owner = false;
+					}
+				}
+				break;
+			} else if (n->get_scene_file_path() != String()) {
+				const Ref<SceneState> &state = n->get_scene_instance_state();
+				_collect_inheritance_chain(state, n->get_path_to(p_node), states_stack);
+			}
+			n = n->get_owner();
+		}
+	}
+
+	// Convert to the proper type for returning, inverting the vector on the go
+	// (it was more convenient to fill the vector in reverse order)
+	Vector<SceneState::PackState> states_stack_ret;
+	{
+		states_stack_ret.resize(states_stack.size());
+		_FastPackState *ps = states_stack.ptr();
+		for (int i = states_stack.size() - 1; i >= 0; --i) {
+			states_stack_ret.write[i].state.reference_ptr(ps->state);
+			states_stack_ret.write[i].node = ps->node;
+			++ps;
+		}
+	}
+	return states_stack_ret;
+}
diff --git a/scene/property_utils.h b/scene/property_utils.h
new file mode 100644
index 0000000000..fde9163548
--- /dev/null
+++ b/scene/property_utils.h
@@ -0,0 +1,51 @@
+/*************************************************************************/
+/*  property_utils.h                                                     */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef PROPERTY_UTILS_H
+#define PROPERTY_UTILS_H
+
+#include "scene/main/node.h"
+#include "scene/resources/packed_scene.h"
+
+class PropertyUtils {
+public:
+	static bool is_property_value_different(const Variant &p_a, const Variant &p_b);
+	// Gets the most pure default value, the one that would be set when the node has just been instantiated
+	static Variant get_property_default_value(const Object *p_object, const StringName &p_property, const Vector<SceneState::PackState> *p_states_stack_cache = nullptr, bool p_update_exports = false, const Node *p_owner = nullptr, bool *r_is_class_default = nullptr);
+
+	// Gets the instance/inheritance states of this node, in order of precedence,
+	// that is, from the topmost (the most able to override values) to the lowermost
+	// (Note that in nested instancing the one with the greatest precedence is the furthest
+	// in the tree, since every owner found while traversing towards the root gets a chance
+	// to override property values.)
+	static Vector<SceneState::PackState> get_node_states_stack(const Node *p_node, const Node *p_owner = nullptr, bool *r_instantiated_by_owner = nullptr);
+};
+
+#endif // PROPERTY_UTILS_H
diff --git a/scene/resources/packed_scene.cpp b/scene/resources/packed_scene.cpp
index 978be2d46e..6eeeccc081 100644
--- a/scene/resources/packed_scene.cpp
+++ b/scene/resources/packed_scene.cpp
@@ -34,10 +34,12 @@
 #include "core/config/project_settings.h"
 #include "core/core_string_names.h"
 #include "core/io/resource_loader.h"
+#include "editor/editor_inspector.h"
 #include "scene/2d/node_2d.h"
 #include "scene/3d/node_3d.h"
 #include "scene/gui/control.h"
 #include "scene/main/instance_placeholder.h"
+#include "scene/property_utils.h"
 
 #define PACKED_SCENE_VERSION 2
 
@@ -415,61 +417,22 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 	// with the instance states, we can query for identical properties/groups
 	// and only save what has changed
 
-	List<PackState> pack_state_stack;
-
-	bool instantiated_by_owner = true;
-
-	{
-		Node *n = p_node;
-
-		while (n) {
-			if (n == p_owner) {
-				Ref<SceneState> state = n->get_scene_inherited_state();
-				if (state.is_valid()) {
-					int node = state->find_node_by_path(n->get_path_to(p_node));
-					if (node >= 0) {
-						//this one has state for this node, save
-						PackState ps;
-						ps.node = node;
-						ps.state = state;
-						pack_state_stack.push_back(ps);
-						instantiated_by_owner = false;
-					}
-				}
-
-				if (p_node->get_scene_file_path() != String() && p_node->get_owner() == p_owner && instantiated_by_owner) {
-					if (p_node->get_scene_instance_load_placeholder()) {
-						//it's a placeholder, use the placeholder path
-						nd.instance = _vm_get_variant(p_node->get_scene_file_path(), variant_map);
-						nd.instance |= FLAG_INSTANCE_IS_PLACEHOLDER;
-					} else {
-						//must instance ourselves
-						Ref<PackedScene> instance = ResourceLoader::load(p_node->get_scene_file_path());
-						if (!instance.is_valid()) {
-							return ERR_CANT_OPEN;
-						}
+	bool instantiated_by_owner = false;
+	Vector<SceneState::PackState> states_stack = PropertyUtils::get_node_states_stack(p_node, p_owner, &instantiated_by_owner);
 
-						nd.instance = _vm_get_variant(instance, variant_map);
-					}
-				}
-				n = nullptr;
-			} else {
-				if (n->get_scene_file_path() != String()) {
-					//is an instance
-					Ref<SceneState> state = n->get_scene_instance_state();
-					if (state.is_valid()) {
-						int node = state->find_node_by_path(n->get_path_to(p_node));
-						if (node >= 0) {
-							//this one has state for this node, save
-							PackState ps;
-							ps.node = node;
-							ps.state = state;
-							pack_state_stack.push_back(ps);
-						}
-					}
-				}
-				n = n->get_owner();
+	if (p_node->get_scene_file_path() != String() && p_node->get_owner() == p_owner && instantiated_by_owner) {
+		if (p_node->get_scene_instance_load_placeholder()) {
+			//it's a placeholder, use the placeholder path
+			nd.instance = _vm_get_variant(p_node->get_scene_file_path(), variant_map);
+			nd.instance |= FLAG_INSTANCE_IS_PLACEHOLDER;
+		} else {
+			//must instance ourselves
+			Ref<PackedScene> instance = ResourceLoader::load(p_node->get_scene_file_path());
+			if (!instance.is_valid()) {
+				return ERR_CANT_OPEN;
 			}
+
+			nd.instance = _vm_get_variant(instance, variant_map);
 		}
 	}
 
@@ -478,90 +441,23 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 
 	List<PropertyInfo> plist;
 	p_node->get_property_list(&plist);
-	StringName type = p_node->get_class();
-
-	Ref<Script> script = p_node->get_script();
-	if (Engine::get_singleton()->is_editor_hint() && script.is_valid()) {
-		// Should be called in the editor only and not at runtime,
-		// otherwise it can cause problems because of missing instance state support.
-		script->update_exports();
-	}
 
 	for (const PropertyInfo &E : plist) {
 		if (!(E.usage & PROPERTY_USAGE_STORAGE)) {
 			continue;
 		}
 
-		String name = E.name;
-		Variant value = p_node->get(E.name);
-
-		bool isdefault = false;
-		Variant default_value = ClassDB::class_get_default_property_value(type, name);
-
-		if (default_value.get_type() != Variant::NIL) {
-			isdefault = bool(Variant::evaluate(Variant::OP_EQUAL, value, default_value));
+		// If instance or inheriting, not saving if property requested so, or it's meta
+		if (states_stack.size() && ((E.usage & PROPERTY_USAGE_NO_INSTANCE_STATE) || E.name == "__meta__")) {
+			continue;
 		}
 
-		if (!isdefault && script.is_valid() && script->get_property_default_value(name, default_value)) {
-			isdefault = bool(Variant::evaluate(Variant::OP_EQUAL, value, default_value));
-		}
-		// the version above makes more sense, because it does not rely on placeholder or usage flag
-		// in the script, just the default value function.
-		// if (E.usage & PROPERTY_USAGE_SCRIPT_DEFAULT_VALUE) {
-		// 	isdefault = true; //is script default value
-		// }
-
-		if (pack_state_stack.size()) {
-			// we are on part of an instantiated subscene
-			// or part of instantiated scene.
-			// only save what has been changed
-			// only save changed properties in instance
-
-			if ((E.usage & PROPERTY_USAGE_NO_INSTANCE_STATE) || E.name == "__meta__") {
-				//property has requested that no instance state is saved, sorry
-				//also, meta won't be overridden or saved
-				continue;
-			}
-
-			bool exists = false;
-			Variant original;
-
-			for (List<PackState>::Element *F = pack_state_stack.back(); F; F = F->prev()) {
-				//check all levels of pack to see if the property exists somewhere
-				const PackState &ps = F->get();
-
-				original = ps.state->get_property_value(ps.node, E.name, exists);
-				if (exists) {
-					break;
-				}
-			}
-
-			if (exists) {
-				//check if already exists and did not change
-				if (value.get_type() == Variant::FLOAT && original.get_type() == Variant::FLOAT) {
-					//this must be done because, as some scenes save as text, there might be a tiny difference in floats due to numerical error
-					float a = value;
-					float b = original;
-
-					if (Math::is_equal_approx(a, b)) {
-						continue;
-					}
-				} else if (bool(Variant::evaluate(Variant::OP_EQUAL, value, original))) {
-					continue;
-				}
-			}
-
-			if (!exists && isdefault) {
-				//does not exist in original node, but it's the default value
-				//so safe to skip too.
-				continue;
-			}
+		String name = E.name;
+		Variant value = p_node->get(name);
 
-		} else {
-			if (isdefault) {
-				//it's the default value, no point in saving it
-				continue;
-			}
+		Variant default_value = PropertyUtils::get_property_default_value(p_node, name, &states_stack, true);
+		if (!PropertyUtils::is_property_value_different(value, default_value)) {
+			continue;
 		}
 
 		NodeData::Property prop;
@@ -585,10 +481,9 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 		*/
 
 		bool skip = false;
-		for (const PackState &F : pack_state_stack) {
+		for (const SceneState::PackState &ia : states_stack) {
 			//check all levels of pack to see if the group was added somewhere
-			const PackState &ps = F;
-			if (ps.state->is_node_in_group(ps.node, gi.name)) {
+			if (ia.state->is_node_in_group(ia.node, gi.name)) {
 				skip = true;
 				break;
 			}
@@ -618,7 +513,7 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 
 	// Save the right type. If this node was created by an instance
 	// then flag that the node should not be created but reused
-	if (pack_state_stack.is_empty() && !is_editable_instance) {
+	if (states_stack.is_empty() && !is_editable_instance) {
 		//this node is not part of an instancing process, so save the type
 		nd.type = _nm_get_string(p_node->get_class(), name_map);
 	} else {
@@ -635,7 +530,7 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 
 	bool save_node = nd.properties.size() || nd.groups.size(); // some local properties or groups exist
 	save_node = save_node || p_node == p_owner; // owner is always saved
-	save_node = save_node || (p_node->get_owner() == p_owner && instantiated_by_owner); //part of scene and not instantiated
+	save_node = save_node || (p_node->get_owner() == p_owner && instantiated_by_owner); //part of scene and not instanced
 
 	int idx = nodes.size();
 	int parent_node = NO_PARENT_SAVED;
@@ -932,7 +827,7 @@ void SceneState::clear() {
 	base_scene_idx = -1;
 }
 
-Ref<SceneState> SceneState::_get_base_scene_state() const {
+Ref<SceneState> SceneState::get_base_scene_state() const {
 	if (base_scene_idx >= 0) {
 		Ref<PackedScene> ps = variants[base_scene_idx];
 		if (ps.is_valid()) {
@@ -947,8 +842,8 @@ int SceneState::find_node_by_path(const NodePath &p_node) const {
 	ERR_FAIL_COND_V_MSG(node_path_cache.size() == 0, -1, "This operation requires the node cache to have been built.");
 
 	if (!node_path_cache.has(p_node)) {
-		if (_get_base_scene_state().is_valid()) {
-			int idx = _get_base_scene_state()->find_node_by_path(p_node);
+		if (get_base_scene_state().is_valid()) {
+			int idx = get_base_scene_state()->find_node_by_path(p_node);
 			if (idx != -1) {
 				int rkey = _find_base_scene_node_remap_key(idx);
 				if (rkey == -1) {
@@ -963,11 +858,11 @@ int SceneState::find_node_by_path(const NodePath &p_node) const {
 
 	int nid = node_path_cache[p_node];
 
-	if (_get_base_scene_state().is_valid() && !base_scene_node_remap.has(nid)) {
+	if (get_base_scene_state().is_valid() && !base_scene_node_remap.has(nid)) {
 		//for nodes that _do_ exist in current scene, still try to look for
 		//the node in the instantiated scene, as a property may be missing
 		//from the local one
-		int idx = _get_base_scene_state()->find_node_by_path(p_node);
+		int idx = get_base_scene_state()->find_node_by_path(p_node);
 		if (idx != -1) {
 			base_scene_node_remap[nid] = idx;
 		}
@@ -1007,7 +902,7 @@ Variant SceneState::get_property_value(int p_node, const StringName &p_property,
 	//property not found, try on instance
 
 	if (base_scene_node_remap.has(p_node)) {
-		return _get_base_scene_state()->get_property_value(base_scene_node_remap[p_node], p_property, found);
+		return get_base_scene_state()->get_property_value(base_scene_node_remap[p_node], p_property, found);
 	}
 
 	return Variant();
@@ -1026,7 +921,7 @@ bool SceneState::is_node_in_group(int p_node, const StringName &p_group) const {
 	}
 
 	if (base_scene_node_remap.has(p_node)) {
-		return _get_base_scene_state()->is_node_in_group(base_scene_node_remap[p_node], p_group);
+		return get_base_scene_state()->is_node_in_group(base_scene_node_remap[p_node], p_group);
 	}
 
 	return false;
@@ -1065,7 +960,7 @@ bool SceneState::is_connection(int p_node, const StringName &p_signal, int p_to_
 	}
 
 	if (base_scene_node_remap.has(p_node) && base_scene_node_remap.has(p_to_node)) {
-		return _get_base_scene_state()->is_connection(base_scene_node_remap[p_node], p_signal, base_scene_node_remap[p_to_node], p_to_method);
+		return get_base_scene_state()->is_connection(base_scene_node_remap[p_node], p_signal, base_scene_node_remap[p_to_node], p_to_method);
 	}
 
 	return false;
@@ -1488,7 +1383,7 @@ bool SceneState::has_connection(const NodePath &p_node_from, const StringName &p
 			}
 		}
 
-		ss = ss->_get_base_scene_state();
+		ss = ss->get_base_scene_state();
 	} while (ss.is_valid());
 
 	return false;
diff --git a/scene/resources/packed_scene.h b/scene/resources/packed_scene.h
index 55708f7914..462e6bb5d2 100644
--- a/scene/resources/packed_scene.h
+++ b/scene/resources/packed_scene.h
@@ -69,11 +69,6 @@ class SceneState : public RefCounted {
 		Vector<int> groups;
 	};
 
-	struct PackState {
-		Ref<SceneState> state;
-		int node = -1;
-	};
-
 	Vector<NodeData> nodes;
 
 	struct ConnectionData {
@@ -94,8 +89,6 @@ class SceneState : public RefCounted {
 
 	uint64_t last_modified_time = 0;
 
-	_FORCE_INLINE_ Ref<SceneState> _get_base_scene_state() const;
-
 	static bool disable_placeholders;
 
 	Vector<String> _get_node_groups(int p_idx) const;
@@ -119,6 +112,11 @@ public:
 		GEN_EDIT_STATE_MAIN,
 	};
 
+	struct PackState {
+		Ref<SceneState> state;
+		int node = -1;
+	};
+
 	static void set_disable_placeholders(bool p_disable);
 
 	int find_node_by_path(const NodePath &p_node) const;
@@ -139,6 +137,8 @@ public:
 	bool can_instantiate() const;
 	Node *instantiate(GenEditState p_edit_state) const;
 
+	Ref<SceneState> get_base_scene_state() const;
+
 	//unbuild API
 
 	int get_node_count() const;