Add helper to set dynamic sized nav meshes

Source/StevesUEHelpers/Private/StevesDynamicNavMeshVolume.cpp

@@ -0,0 +1,55 @@
+
+#include "StevesDynamicNavMeshVolume.h"
+
+#include "NavigationSystem.h"
+#include "Components/BrushComponent.h"
+#include "PhysicsEngine/BodySetup.h"
+
+
+AStevesDynamicNavMeshVolume::AStevesDynamicNavMeshVolume()
+{
+
+}
+
+void AStevesDynamicNavMeshVolume::SetLocationAndDimensions(const FVector& Location, const FVector& NewDimensions)
+{
+	SetActorLocation(Location);
+	UpdateDimensions(NewDimensions);
+	NotifyNavSystem();
+}
+
+void AStevesDynamicNavMeshVolume::SetDimensions(const FVector& NewDimensions)
+{
+	UpdateDimensions(NewDimensions);
+	NotifyNavSystem();
+}
+
+void AStevesDynamicNavMeshVolume::UpdateDimensions(const FVector& NewDimensions)
+{
+	// Volumes are built using UCubeBuilder, but we can't use that class at runtime (Editor only)
+	// It generates the 6 faces as polys, like old BSP stuff. No idea why for a cube, we don't need that here
+	// Just box it baby
+
+	if (auto Body = GetBrushComponent()->GetBodySetup())
+	{
+		Body->AggGeom.ConvexElems.Empty();
+		if (Body->AggGeom.BoxElems.Num() == 0)
+		{
+			Body->AggGeom.BoxElems.Emplace();
+		}
+		auto& Box = Body->AggGeom.BoxElems[0];
+		Box.X = NewDimensions.X;
+		Box.Y = NewDimensions.Y;
+		Box.Z = NewDimensions.Z;
+		GetBrushComponent()->Bounds = FBoxSphereBounds(FVector::ZeroVector, NewDimensions*0.5f, NewDimensions.GetMax()*0.5f);
+	}
+
+}
+
+void AStevesDynamicNavMeshVolume::NotifyNavSystem()
+{
+	if (UNavigationSystemV1* NavSys = FNavigationSystem::GetCurrent<UNavigationSystemV1>(GetWorld()))
+	{
+		NavSys->OnNavigationBoundsUpdated(this);
+	}
+}

Source/StevesUEHelpers/Public/StevesDynamicNavMeshVolume.h

@@ -0,0 +1,24 @@
+// 
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "NavMesh/NavMeshBoundsVolume.h"
+#include "StevesDynamicNavMeshVolume.generated.h"
+
+/// NavMesh bounds that can be changed at runtime (requires that your NavMesh data Runtime Generation is set to Dynamic)
+UCLASS()
+class STEVESUEHELPERS_API AStevesDynamicNavMeshVolume : public ANavMeshBoundsVolume
+{
+	GENERATED_BODY()
+
+public:
+	AStevesDynamicNavMeshVolume();
+
+	void SetLocationAndDimensions(const FVector& Location, const FVector& NewDimensions);
+	void SetDimensions(const FVector& NewDimensions);
+
+protected:
+	void UpdateDimensions(const FVector& NewDimensions);
+	void NotifyNavSystem();
+};

Source/StevesUEHelpers/StevesUEHelpers.Build.cs

@@ -39,7 +39,8 @@ public class StevesUEHelpers : ModuleRules
 			{
 				"RenderCore",
 				"PhysicsCore",
-				"Chaos"
+				"Chaos",
+				"NavigationSystem"
 			}
 			);