DatasmithSceneReceiver.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Map.h"
#include "Containers/SparseArray.h"
#include "DirectLinkCommon.h"
#include "DirectLinkDeltaConsumer.h"
#include "DirectLinkSceneGraphNode.h"
#include "Templates/SharedPointer.h"
#include "Templates/UniquePtr.h"
 
#define UE_API DATASMITHCORE_API
 
class IDatasmithElement;
class IDatasmithScene;
namespace DirectLink { class FElementSnapshot; }
namespace DirectLink { class FSceneSnapshot; }
 
class FDatasmithSceneReceiver
    : public DirectLink::ISceneReceiver
{
public:
    class ISceneChangeListener
    {
    public:
        virtual void OnOpenDelta() = 0;
        virtual void OnNewScene(const DirectLink::FSceneIdentifier& SceneId) = 0;
        virtual void OnAddElement(DirectLink::FSceneGraphId, TSharedPtr<IDatasmithElement> Element) = 0;
        virtual void OnChangedElement(DirectLink::FSceneGraphId, TSharedPtr<IDatasmithElement> Element) = 0;
        virtual void OnRemovedElement(DirectLink::FSceneGraphId ElementId) = 0;
        virtual void OnCloseDelta() = 0;
    };
 
public:
    UE_API FDatasmithSceneReceiver();
 
    // Register a listner that will be notified of important scene edition events
    void SetChangeListener(ISceneChangeListener* Listener) { ChangeListener = Listener; }
 
    // Get the reconstructed DatasmithScene. Can be null.
    UE_API TSharedPtr<IDatasmithScene> GetScene() const;
 
private: // DirectLink::ISceneReceiver API
    UE_API virtual void FinalSnapshot(const DirectLink::FSceneSnapshot& SceneSnapshot) override;
 
    struct FSceneState;
 
    UE_API TUniquePtr<FSceneState> ParseSnapshot(const DirectLink::FSceneSnapshot& SceneSnapshot);
 
private:
    struct FDatasmithElementPointers : public DirectLink::IReferenceResolutionProvider
    {
        // IReferenceResolutionProvider API
        UE_API virtual TSharedPtr<DirectLink::ISceneGraphNode> AsSharedPtr(DirectLink::FSceneGraphId NodeId) override;
        void Reset() { ElementsSharedPtrs.Reset(); }
        void Remove(DirectLink::FSceneGraphId NodeId) { ElementsSharedPtrs.Remove(NodeId); }
        void Add(DirectLink::FSceneGraphId Id, TSharedPtr<IDatasmithElement> Element) { ElementsSharedPtrs.Add(Id, Element); }
        TMap<DirectLink::FSceneGraphId, TSharedPtr<IDatasmithElement>> ElementsSharedPtrs;
    };
 
    struct FFinalizableNode
    {
        TSharedPtr<IDatasmithElement> Element;
        const DirectLink::FElementSnapshot* Snapshot;
    };
 
    ISceneChangeListener* ChangeListener = nullptr;
 
    struct FSceneHashTable
    {
        TMap<DirectLink::FSceneGraphId, DirectLink::FElementHash> ElementHashes;
        static FSceneHashTable FromSceneSnapshot(const DirectLink::FSceneSnapshot& SceneSnapshot);
    };
 
    struct FSceneState
    {
        DirectLink::FSceneIdentifier SceneId;
        TSharedPtr<IDatasmithScene> Scene;
        FDatasmithElementPointers Elements;
        FSceneHashTable HashTable;
    };
 
    TUniquePtr<FSceneState> Current;
};
 
 
#undef UE_API