Add item pickup actor

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -490,7 +490,10 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
 - [x] Create item definition data asset.
 - [x] Create item stack structure.
 - [x] Create inventory component.
-- [ ] Add item pickup.
+- [x] Add item pickup. Added native `AAgrarianItemPickup` interactable world
+  actor with definition-backed or inline stack data, server-authoritative
+  inventory add, prompt text, and destroy-on-success behavior so failed pickups
+  remain available.
 - [ ] Add item drop.
 - [ ] Add stack splitting.
 - [ ] Add item use.

Docs/TechnicalDesignDocument.md

@@ -91,6 +91,14 @@ and save-game `FAgrarianItemStack` records, and a server-authoritative
 splitting, item use, equipment, carry capacity, persistence, and UI work should
 extend that contract rather than inventing parallel inventory state.
 
+World pickups use `AAgrarianItemPickup`, an interactable replicated actor with a
+static mesh and either a definition-backed or inline `FAgrarianItemStack`.
+Player interaction already routes to the server through the Agrarian character,
+so pickups validate authority, produce a valid stack, add it to the player's
+inventory, and only then remove the pickup by destroying the world pickup actor.
+If the inventory is full or the stack is invalid, the pickup remains in the
+world for another attempt.
+
 ## Time And Environment
 
 The MVP gameplay calendar target is:

Scripts/verify_item_pickup.py

@@ -0,0 +1,65 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+FILES = {
+    "AgrarianItemPickup.h": ROOT / "Source" / "AgrarianGame" / "AgrarianItemPickup.h",
+    "AgrarianItemPickup.cpp": ROOT / "Source" / "AgrarianGame" / "AgrarianItemPickup.cpp",
+    "InventoryDataModel.md": ROOT / "Docs" / "InventoryDataModel.md",
+    "TechnicalDesignDocument.md": ROOT / "Docs" / "TechnicalDesignDocument.md",
+    "AGRARIAN_DEVELOPMENT_ROADMAP.md": ROOT / "AGRARIAN_DEVELOPMENT_ROADMAP.md",
+}
+
+EXPECTED = {
+    "AgrarianItemPickup.h": [
+        "class AGRARIANGAME_API AAgrarianItemPickup : public AActor, public IAgrarianInteractable",
+        "TObjectPtr<UStaticMeshComponent> Mesh;",
+        "FAgrarianItemStack PickupStack;",
+        "TObjectPtr<UAgrarianItemDefinitionAsset> ItemDefinition;",
+        "int32 Quantity = 1;",
+        "virtual FText GetInteractionText_Implementation",
+        "virtual bool CanInteract_Implementation",
+        "virtual void Interact_Implementation",
+        "FAgrarianItemStack MakePickupStack() const;",
+    ],
+    "AgrarianItemPickup.cpp": [
+        "bReplicates = true;",
+        "Mesh->SetCollisionProfileName(TEXT(\"BlockAll\"));",
+        "ItemDefinition->MakeStack(Quantity)",
+        "MakePickupStack().IsValidStack()",
+        "if (!HasAuthority() || !Interactor)",
+        "Interactor->GetInventoryComponent()",
+        "Inventory->AddItem(Stack)",
+        "Destroy();",
+    ],
+    "InventoryDataModel.md": [
+        "Pickup:",
+        "world item validates range, authority, stack data, and available",
+    ],
+    "TechnicalDesignDocument.md": [
+        "`AAgrarianItemPickup`",
+        "definition-backed or inline `FAgrarianItemStack`",
+        "destroying the world pickup actor",
+    ],
+    "AGRARIAN_DEVELOPMENT_ROADMAP.md": [
+        "[x] Add item pickup.",
+    ],
+}
+
+
+def main():
+    missing = []
+    for label, path in FILES.items():
+        text = path.read_text(encoding="utf-8")
+        for snippet in EXPECTED[label]:
+            if snippet not in text:
+                missing.append(f"{label}: {snippet}")
+
+    if missing:
+        raise RuntimeError("Item pickup verification failed: " + "; ".join(missing))
+
+    print("Agrarian item pickup verification complete.")
+
+
+if __name__ == "__main__":
+    main()

Source/AgrarianGame/AgrarianItemPickup.cpp

@@ -0,0 +1,76 @@
+// Copyright Pacificao. All Rights Reserved.
+
+#include "AgrarianItemPickup.h"
+#include "AgrarianGameCharacter.h"
+#include "AgrarianInventoryComponent.h"
+#include "AgrarianItemDefinitionAsset.h"
+#include "Components/StaticMeshComponent.h"
+
+AAgrarianItemPickup::AAgrarianItemPickup()
+{
+	bReplicates = true;
+
+	Mesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Mesh"));
+	RootComponent = Mesh;
+	Mesh->SetCollisionProfileName(TEXT("BlockAll"));
+
+	PickupStack.ItemId = TEXT("wood");
+	PickupStack.DisplayName = FText::FromString(TEXT("Wood"));
+	PickupStack.Quantity = 1;
+	PickupStack.UnitWeight = 1.0f;
+	InteractionVerb = FText::FromString(TEXT("Pick up"));
+}
+
+FText AAgrarianItemPickup::GetInteractionText_Implementation(const AAgrarianGameCharacter* Interactor) const
+{
+	const FAgrarianItemStack Stack = MakePickupStack();
+	const FText DisplayName = Stack.DisplayName.IsEmpty() ? FText::FromName(Stack.ItemId) : Stack.DisplayName;
+	const FString Verb = InteractionVerb.IsEmpty() ? FString(TEXT("Pick up")) : InteractionVerb.ToString();
+
+	if (Stack.Quantity > 1)
+	{
+		return FText::FromString(FString::Printf(TEXT("%s %s x%d"), *Verb, *DisplayName.ToString(), Stack.Quantity));
+	}
+
+	return FText::FromString(FString::Printf(TEXT("%s %s"), *Verb, *DisplayName.ToString()));
+}
+
+bool AAgrarianItemPickup::CanInteract_Implementation(const AAgrarianGameCharacter* Interactor) const
+{
+	return Interactor != nullptr && MakePickupStack().IsValidStack();
+}
+
+void AAgrarianItemPickup::Interact_Implementation(AAgrarianGameCharacter* Interactor)
+{
+	if (!HasAuthority() || !Interactor)
+	{
+		return;
+	}
+
+	UAgrarianInventoryComponent* Inventory = Interactor->GetInventoryComponent();
+	if (!Inventory)
+	{
+		return;
+	}
+
+	const FAgrarianItemStack Stack = MakePickupStack();
+	if (Inventory->AddItem(Stack))
+	{
+		Destroy();
+	}
+}
+
+FAgrarianItemStack AAgrarianItemPickup::MakePickupStack() const
+{
+	if (ItemDefinition)
+	{
+		return ItemDefinition->MakeStack(Quantity);
+	}
+
+	FAgrarianItemStack Stack = PickupStack;
+	if (Quantity > 0)
+	{
+		Stack.Quantity = Quantity;
+	}
+	return Stack;
+}

Source/AgrarianGame/AgrarianItemPickup.h

@@ -0,0 +1,44 @@
+// Copyright Pacificao. All Rights Reserved.
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "GameFramework/Actor.h"
+#include "AgrarianInteractable.h"
+#include "AgrarianTypes.h"
+#include "AgrarianItemPickup.generated.h"
+
+class AAgrarianGameCharacter;
+class UAgrarianItemDefinitionAsset;
+class UStaticMeshComponent;
+
+UCLASS(Blueprintable)
+class AGRARIANGAME_API AAgrarianItemPickup : public AActor, public IAgrarianInteractable
+{
+	GENERATED_BODY()
+
+public:
+	AAgrarianItemPickup();
+
+	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Agrarian|Pickup")
+	TObjectPtr<UStaticMeshComponent> Mesh;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|Pickup")
+	FAgrarianItemStack PickupStack;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|Pickup")
+	TObjectPtr<UAgrarianItemDefinitionAsset> ItemDefinition;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|Pickup", meta = (ClampMin = "1"))
+	int32 Quantity = 1;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|Pickup")
+	FText InteractionVerb;
+
+	virtual FText GetInteractionText_Implementation(const AAgrarianGameCharacter* Interactor) const override;
+	virtual bool CanInteract_Implementation(const AAgrarianGameCharacter* Interactor) const override;
+	virtual void Interact_Implementation(AAgrarianGameCharacter* Interactor) override;
+
+	UFUNCTION(BlueprintCallable, Category = "Agrarian|Pickup")
+	FAgrarianItemStack MakePickupStack() const;
+};