DirectLinkDeltaConsumer.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "DirectLinkCommon.h"
 
 
namespace DirectLink
{
class FElementSnapshot;
 
class IDeltaProducer
{
public:
    virtual ~IDeltaProducer() = default;
 
    virtual void OnOpenHaveList(const FSceneIdentifier& HaveSceneId, bool bKeepPreviousContent, int32 SyncCycle) = 0;
    virtual void OnHaveElement(FSceneGraphId NodeId, FElementHash HaveHash) = 0;
    virtual void OnCloseHaveList() = 0;
};
 
 
 
class IDeltaConsumer
{
public:
    virtual ~IDeltaConsumer() = default;
 
    virtual void SetDeltaProducer(IDeltaProducer* Producer) = 0;
 
    // On SetupScene message, the receiver is expected to send it's HaveList
    struct FSetupSceneArg
    {
        FSceneIdentifier SceneId;
        bool bExpectHaveList;
        int32 SyncCycle;
    };
    virtual void SetupScene(FSetupSceneArg& SetupSceneArg) = 0;
 
 
    // signal beginning of a delta
    struct FOpenDeltaArg
    {
        bool bBasedOnNewScene; // start from a fresh scene. (expect only new content)
        uint32 ElementCountHint = 0;
    };
    virtual void OpenDelta(FOpenDeltaArg& OpenDeltaArg) = 0;
 
 
    struct FSetElementArg
    {
        TSharedPtr<FElementSnapshot> Snapshot;
        int32 ElementIndexHint = -1;
    };
    virtual void OnSetElement(FSetElementArg& SetElementArg) = 0;
 
 
    struct FRemoveElementsArg
    {
        TArray<FSceneGraphId> Elements;
    };
    virtual void RemoveElements(FRemoveElementsArg& RemoveElementsArg) = 0;
 
 
    struct FCloseDeltaArg
    {
        bool bCancelled = false; // if an error occured and the delta is unusable
    };
    virtual void OnCloseDelta(FCloseDeltaArg& CloseDeltaArg) = 0;
};
 
 
 
class ISceneReceiver
{
public:
    virtual ~ISceneReceiver() = default;
    virtual void FinalSnapshot(const class FSceneSnapshot& SceneSnapshot) {};
};
 
 
} // namespace DirectLink