From af58f1e8547c8b6a2e6b83b7de9c3ac9bc05d881 Mon Sep 17 00:00:00 2001
From: Rindbee <idleman@yeah.net>
Date: Sun, 14 Aug 2022 19:17:45 +0800
Subject: [PATCH] Improve the UX of ViewportTexture in the editor

The associated `ViewportTexture`s will update the `viewport_path`
in time when the `Viewport`'s nodepath is changed (caused by renaming
the node names or moving in the SceneTree dock).

If the target `Viewport` is changed by resetting the `viewport_path`,
the `ViewportTexture`s will be re-setup and emit `changed` signal in
time.
---
 doc/classes/ViewportTexture.xml |  1 +
 editor/editor_properties.cpp    |  1 -
 scene/main/viewport.cpp         | 46 ++++++++++++++++++++++++++++++---
 scene/main/viewport.h           |  2 ++
 4 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/doc/classes/ViewportTexture.xml b/doc/classes/ViewportTexture.xml
index bf66e466d7d..2f621998139 100644
--- a/doc/classes/ViewportTexture.xml
+++ b/doc/classes/ViewportTexture.xml
@@ -17,6 +17,7 @@
 	<members>
 		<member name="viewport_path" type="NodePath" setter="set_viewport_path_in_scene" getter="get_viewport_path_in_scene" default="NodePath(&quot;&quot;)">
 			The path to the [Viewport] node to display. This is relative to the scene root, not to the node which uses the texture.
+			[b]Note:[/b] In the editor, it is automatically updated when the target viewport's node path changes due to renaming or moving the viewport or its ancestors. At runtime, it may not be able to automatically update due to the inability to determine the scene root.
 		</member>
 	</members>
 </class>
diff --git a/editor/editor_properties.cpp b/editor/editor_properties.cpp
index 18c5d4ba518..d4d115fc77d 100644
--- a/editor/editor_properties.cpp
+++ b/editor/editor_properties.cpp
@@ -4001,7 +4001,6 @@ void EditorPropertyResource::_viewport_selected(const NodePath &p_path) {
 	Ref<ViewportTexture> vt;
 	vt.instantiate();
 	vt->set_viewport_path_in_scene(get_tree()->get_edited_scene_root()->get_path_to(to_node));
-	vt->setup_local_to_scene();
 
 	emit_changed(get_edited_property(), vt);
 	update_property();
diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index e5f95d53934..2c9b8fa63cc 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -72,10 +72,9 @@ void ViewportTexture::setup_local_to_scene() {
 
 	if (vp) {
 		vp->viewport_textures.erase(this);
+		vp = nullptr;
 	}
 
-	vp = nullptr;
-
 	if (loc_scene->is_ready()) {
 		_setup_local_to_scene(loc_scene);
 	} else {
@@ -91,8 +90,24 @@ void ViewportTexture::set_viewport_path_in_scene(const NodePath &p_path) {
 
 	path = p_path;
 
-	if (get_local_scene()) {
+	if (vp) {
+		vp->viewport_textures.erase(this);
+		vp = nullptr;
+	}
+
+	if (proxy_ph.is_valid()) {
+		RS::get_singleton()->free(proxy_ph);
+	}
+	if (proxy.is_valid()) {
+		RS::get_singleton()->free(proxy);
+	}
+	proxy_ph = RID();
+	proxy = RID();
+
+	if (get_local_scene() && !path.is_empty()) {
 		setup_local_to_scene();
+	} else {
+		emit_changed();
 	}
 }
 
@@ -171,6 +186,8 @@ void ViewportTexture::_setup_local_to_scene(const Node *p_loc_scene) {
 		proxy = RS::get_singleton()->texture_proxy_create(vp->texture_rid);
 	}
 	vp_pending = false;
+
+	emit_changed();
 }
 
 void ViewportTexture::_bind_methods() {
@@ -433,9 +450,28 @@ int Viewport::_sub_window_find(Window *p_window) {
 	return -1;
 }
 
+void Viewport::_update_viewport_path() {
+	if (viewport_textures.is_empty()) {
+		return;
+	}
+
+	Node *scene_root = get_scene_file_path().is_empty() ? get_owner() : this;
+	if (!scene_root && is_inside_tree()) {
+		scene_root = get_tree()->get_edited_scene_root();
+	}
+	if (scene_root && (scene_root == this || scene_root->is_ancestor_of(this))) {
+		NodePath path_in_scene = scene_root->get_path_to(this);
+		for (ViewportTexture *E : viewport_textures) {
+			E->path = path_in_scene;
+		}
+	}
+}
+
 void Viewport::_notification(int p_what) {
 	switch (p_what) {
 		case NOTIFICATION_ENTER_TREE: {
+			_update_viewport_path();
+
 			if (get_parent()) {
 				parent = get_parent()->get_viewport();
 				RenderingServer::get_singleton()->viewport_set_parent_viewport(viewport, parent->get_viewport_rid());
@@ -528,6 +564,10 @@ void Viewport::_notification(int p_what) {
 			RenderingServer::get_singleton()->viewport_set_parent_viewport(viewport, RID());
 		} break;
 
+		case NOTIFICATION_PATH_RENAMED: {
+			_update_viewport_path();
+		} break;
+
 		case NOTIFICATION_INTERNAL_PHYSICS_PROCESS: {
 			if (!get_tree()) {
 				return;
diff --git a/scene/main/viewport.h b/scene/main/viewport.h
index a7129f488f3..7f93b21eedc 100644
--- a/scene/main/viewport.h
+++ b/scene/main/viewport.h
@@ -317,6 +317,8 @@ private:
 	Ref<ViewportTexture> default_texture;
 	HashSet<ViewportTexture *> viewport_textures;
 
+	void _update_viewport_path();
+
 	SDFOversize sdf_oversize = SDF_OVERSIZE_120_PERCENT;
 	SDFScale sdf_scale = SDF_SCALE_50_PERCENT;