From f8624ae768abb49d0798d3d87ea3adc65b10f65b Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Thu, 14 Jan 2021 14:18:40 +0100
Subject: [PATCH] Fix crash during navmesh build when actor gets removed

---
 Source/Engine/Navigation/NavMeshBuilder.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Source/Engine/Navigation/NavMeshBuilder.cpp b/Source/Engine/Navigation/NavMeshBuilder.cpp
index 4d62b03b8..a12a72c69 100644
--- a/Source/Engine/Navigation/NavMeshBuilder.cpp
+++ b/Source/Engine/Navigation/NavMeshBuilder.cpp
@@ -628,7 +628,7 @@ class NavMeshTileBuildTask : public ThreadPoolTask
 public:
 
     Scene* Scene;
-    NavMesh* NavMesh;
+    ScriptingObjectReference<NavMesh> NavMesh;
     NavMeshRuntime* Runtime;
     BoundingBox TileBoundsNavMesh;
     Matrix WorldToNavMesh;
@@ -644,6 +644,11 @@ public:
     {
         PROFILE_CPU_NAMED("BuildNavMeshTile");
 
+        const auto navMesh = NavMesh.Get();
+        if (!navMesh)
+        {
+            return false;
+        }
         if (GenerateTile(NavMesh, Runtime, X, Y, TileBoundsNavMesh, WorldToNavMesh, TileSize, Config))
         {
             LOG(Warning, "Failed to generate navmesh tile at {0}x{1}.", X, Y);