Merge pull request #54049 from rxlecky/baked-lightmap-add-no-root-error-53774

doc/classes/BakedLightmap.xml

@@ -16,7 +16,7 @@
 			<argument index="0" name="from_node" type="Node" default="null" />
 			<argument index="1" name="data_save_path" type="String" default="&quot;&quot;" />
 			<description>
-				Bakes the lightmap, scanning from the given [code]from_node[/code] root and saves the resulting [BakedLightmapData] in [code]data_save_path[/code]. If no save path is provided it will try to match the path from the current [member light_data].
+				Bakes the lightmap, scanning from the given [code]from_node[/code] root and saves the resulting [BakedLightmapData] in [code]data_save_path[/code]. If no root node is provided, parent of this node will be used as root instead. If no save path is provided it will try to match the path from the current [member light_data].
 			</description>
 		</method>
 	</methods>
@@ -128,6 +128,10 @@
 			Returns if user cancels baking.
 		</constant>
 		<constant name="BAKE_ERROR_NO_LIGHTMAPPER" value="7" enum="BakeError">
+			Returns if lightmapper can't be created. Unless you are using a custom lightmapper, please report this as bug.
+		</constant>
+		<constant name="BAKE_ERROR_NO_ROOT" value="8" enum="BakeError">
+			There is no root node to start baking from. Either provide [code]from_node[/code] argument or attach this node to a parent that should be used as root.
 		</constant>
 		<constant name="ENVIRONMENT_MODE_DISABLED" value="0" enum="EnvironmentMode">
 			No environment is used during baking.

scene/3d/baked_lightmap.cpp

@@ -572,6 +572,10 @@ bool BakedLightmap::_lightmap_bake_step_function(float p_completion, const Strin
 }
 
 BakedLightmap::BakeError BakedLightmap::bake(Node *p_from_node, String p_data_save_path) {
+	if (!p_from_node && !get_parent()) {
+		return BAKE_ERROR_NO_ROOT;
+	}
+
 	bool no_save_path = false;
 	if (p_data_save_path == "" && (get_light_data().is_null() || !get_light_data()->get_path().is_resource_file())) {
 		no_save_path = true;
@@ -1595,6 +1599,7 @@ void BakedLightmap::_bind_methods() {
 	BIND_ENUM_CONSTANT(BAKE_ERROR_INVALID_MESH);
 	BIND_ENUM_CONSTANT(BAKE_ERROR_USER_ABORTED);
 	BIND_ENUM_CONSTANT(BAKE_ERROR_NO_LIGHTMAPPER);
+	BIND_ENUM_CONSTANT(BAKE_ERROR_NO_ROOT);
 
 	BIND_ENUM_CONSTANT(ENVIRONMENT_MODE_DISABLED);
 	BIND_ENUM_CONSTANT(ENVIRONMENT_MODE_SCENE);

scene/3d/baked_lightmap.h

@@ -120,8 +120,8 @@ public:
 		BAKE_ERROR_LIGHTMAP_SIZE,
 		BAKE_ERROR_INVALID_MESH,
 		BAKE_ERROR_USER_ABORTED,
-		BAKE_ERROR_NO_LIGHTMAPPER
-
+		BAKE_ERROR_NO_LIGHTMAPPER,
+		BAKE_ERROR_NO_ROOT,
 	};
 
 	enum EnvironmentMode {