Initial commit: Item Interaction Ecosystem plugin (UE5.7)

Server-authoritative, data-driven item/inventory/interaction/carry/equipment/
world-slot/placement/crafting framework. 8 modules, compiles against UE 5.7.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/ItemWorld/Private/WorldItemSlotComponent.cpp

@@ -0,0 +1,129 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#include "WorldItemSlotComponent.h"
+#include "PickupItemActor.h"
+#include "ItemWorldLog.h"
+#include "ItemDatabaseSubsystem.h"
+#include "ItemDefinitionRow.h"
+#include "Net/UnrealNetwork.h"
+
+UWorldItemSlotComponent::UWorldItemSlotComponent()
+{
+	PrimaryComponentTick.bCanEverTick = false;
+	SetIsReplicatedByDefault(true);
+}
+
+void UWorldItemSlotComponent::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
+{
+	Super::GetLifetimeReplicatedProps(OutLifetimeProps);
+	DOREPLIFETIME(UWorldItemSlotComponent, InstalledItem);
+	DOREPLIFETIME(UWorldItemSlotComponent, InstalledVisual);
+}
+
+bool UWorldItemSlotComponent::HasAuthority() const
+{
+	return GetOwner() && GetOwner()->HasAuthority();
+}
+
+USceneComponent* UWorldItemSlotComponent::GetAttachTarget() const
+{
+	return GetOwner() ? GetOwner()->GetRootComponent() : nullptr;
+}
+
+bool UWorldItemSlotComponent::CanInstall(const FItemInstanceData& Item) const
+{
+	if (InstalledItem.bHasItem || !Item.IsValid())
+	{
+		return false;
+	}
+	const UItemDatabaseSubsystem* DB = UItemDatabaseSubsystem::Get(this);
+	const FItemDefinitionRow* Def = DB ? DB->GetItemDefinition(Item.ItemId) : nullptr;
+	if (!Def || !Def->bCanInstallIntoWorldSlot)
+	{
+		return false;
+	}
+	// The item must declare this slot as compatible.
+	if (!Def->CompatibleWorldSlots.HasTag(SlotTag))
+	{
+		return false;
+	}
+	// Optional extra tag gate.
+	if (!AcceptedItemTags.IsEmpty())
+	{
+		FGameplayTagContainer ItemTags = Def->ItemTags;
+		ItemTags.AddTag(Def->ItemType);
+		if (!ItemTags.HasAny(AcceptedItemTags))
+		{
+			return false;
+		}
+	}
+	return true;
+}
+
+bool UWorldItemSlotComponent::InstallItem(const FItemInstanceData& Item, AActor* ProvidedVisual)
+{
+	if (!HasAuthority() || !CanInstall(Item))
+	{
+		return false;
+	}
+
+	InstalledItem.bHasItem = true;
+	InstalledItem.Item = Item;
+	InstalledItem.Item.LocationType = EItemLocationType::Installed;
+
+	if (ProvidedVisual)
+	{
+		// Reuse the carried actor as the visual.
+		if (USceneComponent* Target = GetAttachTarget())
+		{
+			ProvidedVisual->AttachToComponent(Target, FAttachmentTransformRules::SnapToTargetIncludingScale, AttachSocketName);
+		}
+		if (IWorldItemProvider* Provider = Cast<IWorldItemProvider>(ProvidedVisual))
+		{
+			Provider->SetCarried(GetOwner(), true); // keep collision off, locked
+		}
+		InstalledVisual = ProvidedVisual;
+	}
+	else
+	{
+		// Spawn a fresh visual pickup and attach it.
+		const FTransform Xf = GetAttachTarget() ? GetAttachTarget()->GetComponentTransform() : GetOwner()->GetActorTransform();
+		if (APickupItemActor* Visual = APickupItemActor::SpawnPickupFromInstance(this, Item, Xf))
+		{
+			Visual->SetCarried(GetOwner(), true);
+			if (USceneComponent* Target = GetAttachTarget())
+			{
+				Visual->AttachToComponent(Target, FAttachmentTransformRules::SnapToTargetIncludingScale, AttachSocketName);
+			}
+			InstalledVisual = Visual;
+		}
+	}
+
+	OnSlotChanged.Broadcast();
+	UE_LOG(LogItemWorld, Log, TEXT("[Interaction] installed %s into %s"), *Item.ItemId.ToString(), *SlotTag.ToString());
+	return true;
+}
+
+bool UWorldItemSlotComponent::RemoveItem(FItemInstanceData& OutItem)
+{
+	if (!HasAuthority() || !InstalledItem.bHasItem)
+	{
+		return false;
+	}
+	OutItem = InstalledItem.Item;
+
+	if (InstalledVisual)
+	{
+		InstalledVisual->Destroy();
+		InstalledVisual = nullptr;
+	}
+
+	InstalledItem = FWorldSlotInstalledState();
+	OnSlotChanged.Broadcast();
+	return true;
+}
+
+void UWorldItemSlotComponent::OnRep_InstalledItem()
+{
+	OnSlotChanged.Broadcast();
+}