IIdentifiableXRDevice.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h" // for FName
#include "HAL/Platform.h"
#include "Templates/TypeHash.h" // for HashCombine()
#include "UObject/NameTypes.h"
#include "UObject/ObjectMacros.h"
 
#include "IIdentifiableXRDevice.generated.h"
 
class IXRSystemIdentifier
{
public:
    virtual FName GetSystemName() const = 0;
};
 
class IIdentifiableXRDevice : public IXRSystemIdentifier
{
public:
    virtual int32 GetSystemDeviceId() const = 0;
 
    friend uint32 GetTypeHash(const IIdentifiableXRDevice& XRDevice)
    {
        const uint32 DomainHash = GetTypeHash(XRDevice.GetSystemName());
        const uint32 DeviceHash = GetTypeHash(XRDevice.GetSystemDeviceId());
        return HashCombine(DomainHash, DeviceHash);
    }
};
 
USTRUCT(BlueprintType)
struct FXRDeviceId
{
    GENERATED_USTRUCT_BODY()
 
public:
    HEADMOUNTEDDISPLAY_API FXRDeviceId();
    HEADMOUNTEDDISPLAY_API FXRDeviceId(IIdentifiableXRDevice* DeviceId);
    HEADMOUNTEDDISPLAY_API FXRDeviceId(IXRSystemIdentifier* OwningSystem, const int32 DeviceId);
 
    HEADMOUNTEDDISPLAY_API bool IsOwnedBy(IXRSystemIdentifier* XRSystem) const;
    HEADMOUNTEDDISPLAY_API void Clear();
    
    bool IsSet() const 
    { 
        // Since DeviceId's value is determined internally by the system, there's 
        // no agreed upon 'invalid' DeviceId, so this is the best way to detect a potentially bad identifier
        return !SystemName.IsNone(); 
    }
 
    HEADMOUNTEDDISPLAY_API bool operator==(const FXRDeviceId& Rhs) const;
    HEADMOUNTEDDISPLAY_API bool operator==(const IIdentifiableXRDevice* Rhs) const;
 
public:
    UPROPERTY(BlueprintReadOnly, Category="XRDevice")
    FName SystemName;
    UPROPERTY(BlueprintReadOnly, Category="XRDevice")
    int32 DeviceId;
};