How and where to save id's of elements for Octree?

Development Programming & Scripting C++
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1

Here The semantics (type traits) for Octree2 (second template parametr) element should define a

SetElementId

method, however I can’t call GetWorld from there to stick the id into my subsystem, from this it is unclear how I can store these id’s to remove unnecessary objects from Octree2?

Code:

// element type
struct FEntityOctreeElement
{
    FMassEntityHandle Entity; 

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Octree Element Struct")
	FBoxSphereBounds BoxSphereBounds;


    FEntityOctreeElement(FMassEntityHandle InEntity, const FVector& InLocation)
        : Entity(InEntity)
    {}

	FEntityOctreeElement()
	{
		BoxSphereBounds = FBoxSphereBounds(FVector(0.0f, 0.0f, 0.0f), FVector(1.0f, 1.0f, 1.0f), 1.0f);
	}

	FEntityOctreeElement(FMassEntityHandle aEntityHandle, FBoxSphereBounds aInBoxSphereBounds)
	{
		Entity = aEntityHandle;
		BoxSphereBounds = aInBoxSphereBounds;
	}

    FBoxSphereBounds GetBounds() const
    {
        return BoxSphereBounds;
    }
};

// semantic
struct FEntityOctreeSemantics
{
	enum { MaxElementsPerLeaf = 2 }; // 16
	enum { MinInclusiveElementsPerNode = 7 };
	enum { MaxNodeDepth = 12 };

	typedef TInlineAllocator<MaxElementsPerLeaf> ElementAllocator;

	/**
	* Get the bounding box of the provided octree element. In this case, the box
	* is merely the point specified by the element.
	*
	* @param	Element	Octree element to get the bounding box for
	*
	* @return	Bounding box of the provided octree element
	*/
	FORCEINLINE static FBoxSphereBounds GetBoundingBox(const FEntityOctreeElement& Element)
	{
		return Element.GetBounds();
	}

	FORCEINLINE static bool AreElementsEqual(const FEntityOctreeElement& A, const FEntityOctreeElement& B)
	{
		return A.Entity == B.Entity;
	}

	FORCEINLINE static void SetElementId(const FEntityOctreeElement& Element, FOctreeElementId2 Id)
    {
          // how to impl it?????
    }

	FORCEINLINE static void ApplyOffset(FEntityOctreeElement& Element, FVector Offset)
	{
		FVector NewPostion = Element.BoxSphereBounds.Origin + Offset;
		Element.BoxSphereBounds.Origin = NewPostion;
	}

};

typedef TOctree2<FEntityOctreeElement, FEntityOctreeSemantics> FEntityOctree; // Octree type