From fd90fc2c9b2d5b2520894ccc69db1fa39cbe43f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Delf=20Neum=C3=A4rker?= <delf@nmrkr.de>
Date: Thu, 18 Feb 2021 22:43:39 +0100
Subject: [PATCH] Fix handling of negative indices in SurfaceTool

(cherry picked from commit 735f75a16bdca48d78469fd0a04e383bf268344b)
---
 scene/resources/surface_tool.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scene/resources/surface_tool.cpp b/scene/resources/surface_tool.cpp
index ed0485d661d..a8c4a74e7c6 100644
--- a/scene/resources/surface_tool.cpp
+++ b/scene/resources/surface_tool.cpp
@@ -266,6 +266,7 @@ void SurfaceTool::add_triangle_fan(const Vector<Vector3> &p_vertices, const Vect
 void SurfaceTool::add_index(int p_index) {
 
 	ERR_FAIL_COND(!begun);
+	ERR_FAIL_COND(p_index < 0);
 
 	format |= Mesh::ARRAY_FORMAT_INDEX;
 	index_array.push_back(p_index);