Implement interaction prompt

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -378,7 +378,7 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
 - [x] Implement crouching and prone movement stances. Decision: `C` toggles crouch at `55%` movement speed and `Z` toggles prone at `25%` movement speed. Gamepad mappings are Right Shoulder for crouch and Left Shoulder for prone. Sprint is disabled while crouched or prone.
 - [x] Implement jumping if needed.
 - [x] Implement interaction trace.
-- [ ] Implement interact prompt.
+- [x] Implement interact prompt. Implemented as a local trace-backed HUD prompt using each interactable's `GetInteractionText`, rendered as `[E] <action>` through the Agrarian HUD.
 - [ ] Implement basic animation blueprint.
 - [x] Implement placeholder character mesh.
 - [~] Add replication for player movement and core state.
@@ -1465,4 +1465,4 @@ Earliest incomplete foundation items:
 
 Immediate next item:
 
-- [ ] Implement interact prompt.
+- [ ] Implement basic animation blueprint.

Scripts/setup_interaction_prompt.py

@@ -0,0 +1,24 @@
+import unreal
+
+
+def load(path):
+    asset = unreal.EditorAssetLibrary.load_asset(path)
+    if not asset:
+        raise RuntimeError(f"Could not load {path}")
+    return asset
+
+
+def main():
+    game_mode_bp = load("/Game/ThirdPerson/Blueprints/BP_ThirdPersonGameMode")
+    game_mode_cdo = unreal.get_default_object(game_mode_bp.generated_class())
+    hud_class = unreal.load_class(None, "/Script/AgrarianGame.AgrarianDebugHUD")
+    if not hud_class:
+        raise RuntimeError("Could not load /Script/AgrarianGame.AgrarianDebugHUD")
+
+    game_mode_cdo.set_editor_property("hud_class", hud_class)
+    unreal.EditorAssetLibrary.save_loaded_asset(game_mode_bp)
+
+    unreal.log("Agrarian interaction prompt setup complete.")
+
+
+main()

Scripts/verify_interaction_prompt.py

@@ -0,0 +1,42 @@
+import unreal
+
+
+def load(path):
+    asset = unreal.EditorAssetLibrary.load_asset(path)
+    if not asset:
+        raise RuntimeError(f"Could not load {path}")
+    return asset
+
+
+def main():
+    game_mode_bp = load("/Game/ThirdPerson/Blueprints/BP_ThirdPersonGameMode")
+    game_mode_cdo = unreal.get_default_object(game_mode_bp.generated_class())
+    expected_hud_class = unreal.load_class(None, "/Script/AgrarianGame.AgrarianDebugHUD")
+    character_class = unreal.load_class(None, "/Script/AgrarianGame.AgrarianGameCharacter")
+    hud_cdo = unreal.get_default_object(expected_hud_class) if expected_hud_class else None
+    character_cdo = unreal.get_default_object(character_class) if character_class else None
+
+    missing = []
+    if not expected_hud_class:
+        missing.append("could not load AgrarianDebugHUD class")
+    elif game_mode_cdo.get_editor_property("hud_class") != expected_hud_class:
+        missing.append("BP_ThirdPersonGameMode HUD class is not AgrarianDebugHUD")
+    elif hud_cdo:
+        if not bool(hud_cdo.get_editor_property("bShowInteractionPrompt")):
+            missing.append("AgrarianDebugHUD bShowInteractionPrompt is disabled")
+        if float(hud_cdo.get_editor_property("PromptTextScale")) <= 0.0:
+            missing.append("AgrarianDebugHUD PromptTextScale is not positive")
+
+    if not character_class:
+        missing.append("could not load AgrarianGameCharacter class")
+    elif character_cdo:
+        character_cdo.get_editor_property("InteractionPromptText")
+        character_cdo.get_editor_property("FocusedInteractableActor")
+
+    if missing:
+        raise RuntimeError("Interaction prompt verification failed: " + "; ".join(missing))
+
+    unreal.log("Agrarian interaction prompt verification complete.")
+
+
+main()

Source/AgrarianGame/AgrarianDebugHUD.cpp

@@ -4,12 +4,13 @@
 #include "AgrarianGameCharacter.h"
 #include "AgrarianInventoryComponent.h"
 #include "AgrarianSurvivalComponent.h"
+#include "Engine/Canvas.h"
 
 void AAgrarianDebugHUD::DrawHUD()
 {
 	Super::DrawHUD();
 
-	if (!bShowDebugHUD || !Canvas)
+	if (!Canvas)
 	{
 		return;
 	}
@@ -20,12 +21,34 @@ void AAgrarianDebugHUD::DrawHUD()
 		return;
 	}
 
-	float Y = 32.0f;
-	constexpr float X = 32.0f;
+	DrawInteractionPrompt(AgrarianCharacter);
 
-	DrawLine(TEXT("AGRARIAN DEV HUD"), X, Y, FColor(160, 220, 140));
-	DrawSurvival(AgrarianCharacter->GetSurvivalComponent(), X, Y);
-	DrawInventory(AgrarianCharacter->GetInventoryComponent(), X, Y);
+	if (bShowDebugHUD)
+	{
+		float Y = 32.0f;
+		constexpr float X = 32.0f;
+
+		DrawLine(TEXT("AGRARIAN DEV HUD"), X, Y, FColor(160, 220, 140));
+		DrawSurvival(AgrarianCharacter->GetSurvivalComponent(), X, Y);
+		DrawInventory(AgrarianCharacter->GetInventoryComponent(), X, Y);
+	}
+}
+
+void AAgrarianDebugHUD::DrawInteractionPrompt(const AAgrarianGameCharacter* AgrarianCharacter)
+{
+	if (!bShowInteractionPrompt || !AgrarianCharacter || !AgrarianCharacter->HasInteractionPrompt() || !Canvas)
+	{
+		return;
+	}
+
+	const FString Prompt = FString::Printf(TEXT("[E] %s"), *AgrarianCharacter->GetInteractionPromptText().ToString());
+	float TextWidth = 0.0f;
+	float TextHeight = 0.0f;
+	GetTextSize(Prompt, TextWidth, TextHeight, nullptr, PromptTextScale);
+
+	const float X = (Canvas->ClipX - TextWidth) * 0.5f;
+	const float Y = Canvas->ClipY * 0.62f;
+	DrawText(Prompt, FColor(245, 245, 225), X, Y, nullptr, PromptTextScale, true);
 }
 
 void AAgrarianDebugHUD::DrawSurvival(const UAgrarianSurvivalComponent* SurvivalComponent, float X, float& Y)

Source/AgrarianGame/AgrarianDebugHUD.h

@@ -23,7 +23,14 @@ public:
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|HUD", meta = (ClampMin = "0.25"))
 	float TextScale = 1.0f;
 
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|HUD")
+	bool bShowInteractionPrompt = true;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Agrarian|HUD", meta = (ClampMin = "0.25"))
+	float PromptTextScale = 1.15f;
+
 protected:
+	void DrawInteractionPrompt(const class AAgrarianGameCharacter* AgrarianCharacter);
 	void DrawSurvival(const UAgrarianSurvivalComponent* SurvivalComponent, float X, float& Y);
 	void DrawInventory(const UAgrarianInventoryComponent* InventoryComponent, float X, float& Y);
 	void DrawLine(const FString& Text, float X, float& Y, const FColor& Color = FColor::White);

Source/AgrarianGame/AgrarianGameCharacter.cpp

@@ -69,6 +69,11 @@ void AAgrarianGameCharacter::Tick(float DeltaSeconds)
 {
 	Super::Tick(DeltaSeconds);
 
+	if (IsLocallyControlled())
+	{
+		UpdateInteractionPrompt();
+	}
+
 	ApplyMovementSpeed();
 
 	if (!HasAuthority() || !bWantsToSprint)
@@ -498,6 +503,36 @@ void AAgrarianGameCharacter::DoJumpEnd()
 }
 
 void AAgrarianGameCharacter::TryInteract()
+{
+	AActor* HitActor = FindFocusedInteractable();
+	if (!HitActor)
+	{
+		return;
+	}
+
+	if (HasAuthority())
+	{
+		IAgrarianInteractable::Execute_Interact(HitActor, this);
+	}
+	else
+	{
+		ServerInteract(HitActor);
+	}
+}
+
+bool AAgrarianGameCharacter::HasInteractionPrompt() const
+{
+	return FocusedInteractableActor != nullptr && !InteractionPromptText.IsEmpty();
+}
+
+void AAgrarianGameCharacter::UpdateInteractionPrompt()
+{
+	FText NewPromptText;
+	FocusedInteractableActor = FindFocusedInteractable(&NewPromptText);
+	InteractionPromptText = FocusedInteractableActor ? NewPromptText : FText::GetEmpty();
+}
+
+AActor* AAgrarianGameCharacter::FindFocusedInteractable(FText* OutPromptText) const
 {
 	FVector TraceStart;
 	FRotator TraceRotation;
@@ -518,26 +553,26 @@ void AAgrarianGameCharacter::TryInteract()
 
 	if (!GetWorld() || !GetWorld()->LineTraceSingleByChannel(Hit, TraceStart, TraceEnd, ECC_Visibility, Params))
 	{
-		return;
+		return nullptr;
 	}
 
 	AActor* HitActor = Hit.GetActor();
 	if (!HitActor || !HitActor->GetClass()->ImplementsInterface(UAgrarianInteractable::StaticClass()))
 	{
-		return;
+		return nullptr;
 	}
 
-	if (HasAuthority())
+	if (!IAgrarianInteractable::Execute_CanInteract(HitActor, this))
 	{
-		if (IAgrarianInteractable::Execute_CanInteract(HitActor, this))
-		{
-			IAgrarianInteractable::Execute_Interact(HitActor, this);
-		}
+		return nullptr;
 	}
-	else
+
+	if (OutPromptText)
 	{
-		ServerInteract(HitActor);
+		*OutPromptText = IAgrarianInteractable::Execute_GetInteractionText(HitActor, this);
 	}
+
+	return HitActor;
 }
 
 void AAgrarianGameCharacter::ServerSetWantsToSprint_Implementation(bool bNewWantsToSprint)

Source/AgrarianGame/AgrarianGameCharacter.h

@@ -93,6 +93,14 @@ protected:
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Agrarian|Interaction", meta = (ClampMin = "100"))
 	float InteractionDistance = 450.0f;
 
+	/** Actor currently under the local interaction trace. */
+	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Agrarian|Interaction", meta = (AllowPrivateAccess = "true"))
+	TObjectPtr<AActor> FocusedInteractableActor = nullptr;
+
+	/** Prompt text for the currently focused interactable. */
+	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Agrarian|Interaction", meta = (AllowPrivateAccess = "true"))
+	FText InteractionPromptText;
+
 	/** Baseline movement speed before sprint, skill, injury, load, and terrain modifiers. */
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Agrarian|Movement", meta = (ClampMin = "0"))
 	float WalkSpeed = 140.0f;
@@ -252,6 +260,18 @@ public:
 	UFUNCTION(BlueprintCallable, Category="Agrarian|Interaction")
 	virtual void TryInteract();
 
+	/** Returns true when the local interaction trace has a usable target. */
+	UFUNCTION(BlueprintPure, Category="Agrarian|Interaction")
+	bool HasInteractionPrompt() const;
+
+	/** Returns the current local interaction prompt text. */
+	UFUNCTION(BlueprintPure, Category="Agrarian|Interaction")
+	FText GetInteractionPromptText() const { return InteractionPromptText; }
+
+	/** Returns the actor currently under the local interaction trace, if any. */
+	UFUNCTION(BlueprintPure, Category="Agrarian|Interaction")
+	AActor* GetFocusedInteractableActor() const { return FocusedInteractableActor; }
+
 	/** Returns true when this local character is using first-person camera presentation. */
 	UFUNCTION(BlueprintPure, Category="Agrarian|Camera")
 	bool IsFirstPersonCamera() const { return bFirstPersonCamera; }
@@ -287,6 +307,12 @@ public:
 	UFUNCTION(Server, Reliable)
 	void ServerSetProne(bool bNewProne);
 
+	/** Refreshes local interactable focus and prompt text. */
+	void UpdateInteractionPrompt();
+
+	/** Finds a valid interactable in front of this character. */
+	AActor* FindFocusedInteractable(FText* OutPromptText = nullptr) const;
+
 public:
 
 	/** Returns CameraBoom subobject **/

Source/AgrarianGame/AgrarianGameGameMode.cpp

@@ -1,9 +1,11 @@
 // Copyright Epic Games, Inc. All Rights Reserved.
 
 #include "AgrarianGameGameMode.h"
+#include "AgrarianDebugHUD.h"
 #include "AgrarianGameState.h"
 
 AAgrarianGameGameMode::AAgrarianGameGameMode()
 {
 	GameStateClass = AAgrarianGameState::StaticClass();
+	HUDClass = AAgrarianDebugHUD::StaticClass();
 }