From d19c31555b457f8e9beaee82981c51f66989390a Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 18 Jan 2021 15:08:00 +0100
Subject: [PATCH] Add support for dynamic updating navmesh when moving
 NavModifierVolume

---
 .../Engine/Navigation/NavModifierVolume.cpp   | 26 +++++++++++++++----
 Source/Engine/Navigation/NavModifierVolume.h  |  2 +-
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/Source/Engine/Navigation/NavModifierVolume.cpp b/Source/Engine/Navigation/NavModifierVolume.cpp
index 533fae199..e72393a03 100644
--- a/Source/Engine/Navigation/NavModifierVolume.cpp
+++ b/Source/Engine/Navigation/NavModifierVolume.cpp
@@ -2,12 +2,12 @@
 
 #include "NavModifierVolume.h"
 #include "NavigationSettings.h"
+#include "NavMeshBuilder.h"
 #include "Engine/Level/Scene/Scene.h"
 #include "Engine/Serialization/Serialization.h"
 #if USE_EDITOR
 #include "Editor/Editor.h"
 #include "Editor/Managed/ManagedEditor.h"
-#include "NavMeshBuilder.h"
 #endif
 
 NavModifierVolume::NavModifierVolume(const SpawnParams& params)
@@ -47,19 +47,35 @@ void NavModifierVolume::Deserialize(DeserializeStream& stream, ISerializeModifie
     DESERIALIZE(AreaName);
 }
 
-#if USE_EDITOR
-
 void NavModifierVolume::OnBoundsChanged(const BoundingBox& prevBounds)
 {
+#if COMPILE_WITH_NAV_MESH_BUILDER
     // Auto-rebuild modified navmesh area
-    if (IsDuringPlay() && IsActiveInHierarchy() && !Editor::IsPlayMode && Editor::Managed->CanAutoBuildNavMesh())
+    if (
+        IsDuringPlay() && IsActiveInHierarchy() && HasStaticFlag(StaticFlags::Navigation) &&
+        (
+            // Build at runtime for dynamic modifiers
+            !HasStaticFlag(StaticFlags::Transform)
+#if USE_EDITOR
+            // Build in editor when using auto-rebuild option
+            || (!Editor::IsPlayMode && Editor::Managed->CanAutoBuildNavMesh())
+#endif
+        ))
     {
         BoundingBox dirtyBounds;
         BoundingBox::Merge(prevBounds, _box, dirtyBounds);
-        NavMeshBuilder::Build(GetScene(), dirtyBounds, ManagedEditor::ManagedEditorOptions.AutoRebuildNavMeshTimeoutMs);
+#if USE_EDITOR
+        const float timeoutMs = ManagedEditor::ManagedEditorOptions.AutoRebuildNavMeshTimeoutMs;
+#else
+        const float timeoutMs = 0.0f;
+#endif
+        NavMeshBuilder::Build(GetScene(), dirtyBounds, timeoutMs);
     }
+#endif
 }
 
+#if USE_EDITOR
+
 Color NavModifierVolume::GetWiresColor()
 {
     return Color::Red;
diff --git a/Source/Engine/Navigation/NavModifierVolume.h b/Source/Engine/Navigation/NavModifierVolume.h
index 7ee70c116..9b6a3e764 100644
--- a/Source/Engine/Navigation/NavModifierVolume.h
+++ b/Source/Engine/Navigation/NavModifierVolume.h
@@ -41,8 +41,8 @@ public:
 protected:
 
     // [BoxVolume]
-#if USE_EDITOR
     void OnBoundsChanged(const BoundingBox& prevBounds) override;
+#if USE_EDITOR
     Color GetWiresColor() override;
 #endif
 };