DirectLinkSceneGraphNode.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
#include "Containers/UnrealString.h"
#include "DirectLinkCommon.h"
#include "HAL/Platform.h"
#include "Misc/Guid.h"
#include "Templates/SharedPointer.h"
#include "UObject/NameTypes.h"
 
#define UE_API DIRECTLINK_API
 
 
namespace DirectLink
{
class FParameterStore;
class FSnapshotProxy;
class IReferenceProxy;
struct FReferenceSnapshot;
 
 
class FSceneGraphSharedState
{
public:
    FSceneGraphId MakeId() { return ++LastElementId; }
    const FGuid& GetGuid() const { return SceneId.SceneGuid; }
    const FSceneIdentifier& GetSceneId() const { return SceneId; }
 
protected:
    FSceneGraphId LastElementId = InvalidId;
    FSceneIdentifier SceneId{FGuid::NewGuid(), FString()};
};
 
 
class ISceneGraphNode
{
public:
    virtual ~ISceneGraphNode() = default;
 
    virtual TSharedPtr<FSceneGraphSharedState> MakeSharedState() const { return MakeShared<FSceneGraphSharedState>(); }
    virtual TSharedPtr<FSceneGraphSharedState> GetSharedState() const { return SharedState; }
    UE_API void SetSharedState(TSharedPtr<FSceneGraphSharedState> NewSharedState);
 
    virtual const FParameterStore& GetStore() const = 0;
    virtual FParameterStore& GetStore() = 0; // protected ?
 
    virtual void CustomSerialize(class FSnapshotProxy& Ar) {}
    void CustomSerialize(class FSnapshotProxy& Ar) const { const_cast<ISceneGraphNode*>(this)->CustomSerialize(Ar); }
 
    // This Id is unique within a SceneGraph
    FSceneGraphId GetNodeId() const { return SceneGraphId; }
    //private: friend class ...  #ue_directlink_design -> only accessible from the scene that owns the dep graph
    void SetNodeId(FSceneGraphId Id) { SceneGraphId = Id; }
 
    UE_API void RegisterReferenceProxy(class IReferenceProxy& View, FName Name);
    UE_API int32 GetReferenceProxyCount() const;
    UE_API class IReferenceProxy* GetReferenceProxy(int32 Index) const;
    UE_API FName GetReferenceProxyName(int32 Index) const;
 
    UE_API FSceneGraphId RegisterReference(ISceneGraphNode* Referenced);
    UE_API void UpdateRefs(class IReferenceResolutionProvider& Resolver, const FReferenceSnapshot& NewRefs);
    // #ue_directlink_design is node responsible for ref serialization?
 
private:
    FSceneGraphId SceneGraphId = 0;
    TSharedPtr<FSceneGraphSharedState> SharedState;
 
    struct FNamedReferenceProxy
    {
        FName Name;
        IReferenceProxy* View;
    };
    TArray<FNamedReferenceProxy> ReferenceProxies;
};
 
class IReferenceResolutionProvider // #ue_directlink_design: improve: ClaimRef in the ds shared state
{
public:
    virtual ~IReferenceResolutionProvider() = default;
    virtual TSharedPtr<ISceneGraphNode> AsSharedPtr(FSceneGraphId NodeId) { return nullptr; }
};
 
class IReferenceProxy
{
public:
    virtual ~IReferenceProxy() = default;
    virtual int32 Num() const = 0;
    virtual ISceneGraphNode* GetNode(int32 Index) const = 0;
    virtual void SetNodes(IReferenceResolutionProvider& ResolutionProvider, const TArray<FSceneGraphId>& NodeIds) = 0;
};
 
} // namespace DirectLink
 
#undef UE_API