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/ItemInteraction/Private/InteractionTraceComponent.cpp

@@ -0,0 +1,86 @@
+// Copyright ExByte Studios. Item Interaction Ecosystem.
+
+#include "InteractionTraceComponent.h"
+#include "InteractableComponent.h"
+#include "GameFramework/Pawn.h"
+#include "GameFramework/PlayerController.h"
+#include "Engine/World.h"
+
+UInteractionTraceComponent::UInteractionTraceComponent()
+{
+	PrimaryComponentTick.bCanEverTick = true;
+	PrimaryComponentTick.TickInterval = 0.1f; // 10 Hz is plenty for prompts
+	SetIsReplicatedByDefault(false);          // purely local
+}
+
+void UInteractionTraceComponent::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
+{
+	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);
+	TickTrace();
+}
+
+bool UInteractionTraceComponent::GetViewPoint(FVector& OutLocation, FRotator& OutRotation) const
+{
+	const APawn* Pawn = Cast<APawn>(GetOwner());
+	const APlayerController* PC = Pawn ? Cast<APlayerController>(Pawn->GetController()) : nullptr;
+	if (!PC || !PC->IsLocalController())
+	{
+		return false;
+	}
+	PC->GetPlayerViewPoint(OutLocation, OutRotation);
+	return true;
+}
+
+void UInteractionTraceComponent::TickTrace()
+{
+	FVector ViewLoc;
+	FRotator ViewRot;
+	if (!GetViewPoint(ViewLoc, ViewRot))
+	{
+		SetTarget(nullptr, nullptr);
+		return;
+	}
+
+	const FVector End = ViewLoc + ViewRot.Vector() * TraceDistance;
+
+	FCollisionQueryParams Params(SCENE_QUERY_STAT(InteractionTrace), false, GetOwner());
+	Params.bTraceComplex = false;
+
+	FHitResult Hit;
+	const bool bHit = GetWorld()->SweepSingleByChannel(
+		Hit, ViewLoc, End, FQuat::Identity, TraceChannel,
+		FCollisionShape::MakeSphere(TraceRadius), Params);
+
+	AActor* HitActor = bHit ? Hit.GetActor() : nullptr;
+	UInteractableComponent* Interactable = HitActor ? HitActor->FindComponentByClass<UInteractableComponent>() : nullptr;
+
+	if (Interactable)
+	{
+		// Distance gate against the component's own reach.
+		const float DistSq = FVector::DistSquared(ViewLoc, Hit.ImpactPoint);
+		if (DistSq > FMath::Square(Interactable->InteractionDistance))
+		{
+			Interactable = nullptr;
+			HitActor = nullptr;
+		}
+	}
+	else
+	{
+		HitActor = nullptr;
+	}
+
+	LastHitLocation = Hit.ImpactPoint;
+	LastHitNormal = Hit.ImpactNormal;
+	SetTarget(HitActor, Interactable);
+}
+
+void UInteractionTraceComponent::SetTarget(AActor* NewTarget, UInteractableComponent* NewInteractable)
+{
+	if (CurrentTarget == NewTarget && CurrentInteractable == NewInteractable)
+	{
+		return;
+	}
+	CurrentTarget = NewTarget;
+	CurrentInteractable = NewInteractable;
+	OnTargetChanged.Broadcast(NewTarget, NewInteractable);
+}