From 98c0ffb749dfc94afcedabedb713a6d299293fc8 Mon Sep 17 00:00:00 2001
From: SeleckyErik <35656626+SeleckyErik@users.noreply.github.com>
Date: Thu, 21 Oct 2021 02:29:28 +0200
Subject: [PATCH] Add BAKE_ERROR_NO_ROOT to BakedLightmap

Add new error type to BakeError to signalise that there is no root node to
start baking from.
Document the new error type, as well as BAKE_ERROR_NO_LIGHTMAPPER.
---
 doc/classes/BakedLightmap.xml | 6 +++++-
 scene/3d/baked_lightmap.cpp   | 5 +++++
 scene/3d/baked_lightmap.h     | 4 ++--
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/doc/classes/BakedLightmap.xml b/doc/classes/BakedLightmap.xml
index c206b517ef6..d1605334e27 100644
--- a/doc/classes/BakedLightmap.xml
+++ b/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.
diff --git a/scene/3d/baked_lightmap.cpp b/scene/3d/baked_lightmap.cpp
index b40385b0f90..3aa94ba5401 100644
--- a/scene/3d/baked_lightmap.cpp
+++ b/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);
diff --git a/scene/3d/baked_lightmap.h b/scene/3d/baked_lightmap.h
index 54a85dc8eee..8ef28267b89 100644
--- a/scene/3d/baked_lightmap.h
+++ b/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 {