From a49e3bb449b88bfa9eded62a86fa92ab70d588c8 Mon Sep 17 00:00:00 2001
From: Hugo Locurcio <hugo.locurcio@hugo.pro>
Date: Sun, 14 Nov 2021 22:46:42 +0100
Subject: [PATCH] Document low performance when using
 `SurfaceTool.append_from()` in thread

(cherry picked from commit f39375d315dc67e53ecdeb5964ffad59959c888f)
---
 doc/classes/SurfaceTool.xml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/classes/SurfaceTool.xml b/doc/classes/SurfaceTool.xml
index f04dd3a3741..78834d4a5fc 100644
--- a/doc/classes/SurfaceTool.xml
+++ b/doc/classes/SurfaceTool.xml
@@ -113,6 +113,7 @@
 			<argument index="2" name="transform" type="Transform" />
 			<description>
 				Append vertices from a given [Mesh] surface onto the current vertex array with specified [Transform].
+				[b]Note:[/b] Using [method append_from] on a [Thread] is much slower as the GPU must communicate data back to the CPU, while also causing the main thread to stall (as OpenGL is not thread-safe). Consider requesting a copy of the mesh, converting it to an [ArrayMesh] and adding vertices manually instead.
 			</description>
 		</method>
 		<method name="begin">