From bcad569ed9c2d547dbf48b40ef7db25c41015732 Mon Sep 17 00:00:00 2001
From: nikitalita <69168929+nikitalita@users.noreply.github.com>
Date: Wed, 10 Jan 2024 08:56:04 -0800
Subject: [PATCH] Skeleton3D: Convert 3.x skeletons

---
 scene/3d/skeleton_3d.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scene/3d/skeleton_3d.cpp b/scene/3d/skeleton_3d.cpp
index 445c1003b5dd..11a79d636dde 100644
--- a/scene/3d/skeleton_3d.cpp
+++ b/scene/3d/skeleton_3d.cpp
@@ -95,6 +95,19 @@ bool Skeleton3D::_set(const StringName &p_path, const Variant &p_value) {
 		set_bone_pose_rotation(which, p_value);
 	} else if (what == "scale") {
 		set_bone_pose_scale(which, p_value);
+#ifndef DISABLE_DEPRECATED
+	} else if (what == "pose") {
+		// Kept for compatibility from 3.x to 4.x.
+		WARN_DEPRECATED_MSG("Skeleton uses old pose format, which is deprecated (and loads slower). Consider re-importing or re-saving the scene." +
+				(is_inside_tree() ? vformat(" Path: \"%s\"", get_path()) : String()));
+		// Old Skeleton poses were relative to rest, new ones are absolute, so we need to recompute the pose.
+		// Skeleton3D nodes were always written with rest before pose, so this *SHOULD* work...
+		Transform3D rest = get_bone_rest(which);
+		Transform3D pose = rest * (Transform3D)p_value;
+		set_bone_pose_position(which, pose.origin);
+		set_bone_pose_rotation(which, pose.basis.get_rotation_quaternion());
+		set_bone_pose_scale(which, pose.basis.get_scale());
+#endif
 	} else {
 		return false;
 	}