highlight enemies

Config/DefaultEditorPerProjectUserSettings.ini

@@ -2,7 +2,7 @@
 bEnabled=False
 Startup=AutomaticButHidden
 bEnableReinstancing=True
-bAutomaticallyCompileNewClasses=True
+bAutomaticallyCompileNewClasses=False
 bPreloadEngineModules=False
 bPreloadEnginePluginModules=False
 bPreloadProjectModules=True

Source/Aura/Aura.h

@@ -1,4 +1,4 @@
-// Fill out your copyright notice in the Description page of Project Settings.
+// Copyright; GhostPacket Games
 
 #pragma once
 

Source/Aura/Private/Character/AuraEnemy.cpp

@@ -3,3 +3,12 @@
 
 #include "Character/AuraEnemy.h"
 
+void AAuraEnemy::HighlightActor()
+{
+	bHighlighted = true;
+}
+
+void AAuraEnemy::UnHighlightActor()
+{
+	bHighlighted = false;
+}

Source/Aura/Private/Interaction/EnemyInterface.cpp

@@ -0,0 +1,6 @@
+// Copyright; GhostPacket Games
+
+
+#include "Interaction/EnemyInterface.h"
+
+// Add default functionality here for any IEnemyInterface functions that are not pure virtual.

Source/Aura/Private/Player/AuraPlayerController.cpp

@@ -5,12 +5,75 @@
 
 #include "EnhancedInputSubsystems.h"
 #include "EnhancedInputComponent.h"
+#include "Interaction/EnemyInterface.h"
 
 AAuraPlayerController::AAuraPlayerController()
 {
 	bReplicates = true;
 }
 
+void AAuraPlayerController::PlayerTick(float DeltaTime)
+{
+	Super::PlayerTick(DeltaTime);
+
+	CursorTrace();
+}
+
+void AAuraPlayerController::CursorTrace()
+{
+	FHitResult CursorHit;
+	GetHitResultUnderCursor(ECC_Visibility, false, CursorHit);
+	if (!CursorHit.bBlockingHit)
+		return;
+
+	LastActor = ThisActor;
+	ThisActor = CursorHit.GetActor();
+
+	/*
+	 * Line tracer from cursor. There are several scenarios:
+	 *  A. LastActor is null && ThisActor is null
+	 *    - Do nothing.
+	 *  B. LastActor is null && ThisActor is valid
+	 *    - Highlight ThisActor.
+	 *  C. LastActor is valid && ThisActor is null
+	 *    - UnHighlight LastActor
+	 *  D. Both actors are valid, but LastActor != ThisActor
+	 *    - UnHighlight LastActor.
+	 *    - Highlight ThisActor.
+	 *  E. Both actors are valid, and are the same actor
+	 *    - Do nothing.
+	 */
+
+	if (!LastActor)
+	{
+		if (ThisActor)
+		{
+			// Case B
+			ThisActor->HighlightActor();
+		}
+		// else Case A
+	}
+	else // LastActor is valid
+	{
+		if (!ThisActor)
+		{
+			// Case C
+			LastActor->UnHighlightActor();
+		}
+		else
+		{
+			// Both Actors are valid
+			if (LastActor != ThisActor)
+			{
+				// Case D
+				LastActor->UnHighlightActor();
+				ThisActor->HighlightActor();
+			}
+			// else do nothing
+		}
+	}
+}
+
 void AAuraPlayerController::BeginPlay()
 {
 	Super::BeginPlay();

Source/Aura/Public/Character/AuraEnemy.h

@@ -4,14 +4,21 @@
 
 #include "CoreMinimal.h"
 #include "Character/AuraCharacterBase.h"
+#include "Interaction/EnemyInterface.h"
 #include "AuraEnemy.generated.h"
 
 /**
  * 
  */
 UCLASS()
-class AURA_API AAuraEnemy : public AAuraCharacterBase
+class AURA_API AAuraEnemy : public AAuraCharacterBase, public IEnemyInterface
 {
 	GENERATED_BODY()
 
+public:
+	virtual void HighlightActor() override;
+	virtual void UnHighlightActor() override;
+	
+	UPROPERTY (BlueprintReadOnly)
+	bool bHighlighted = false;
 };

Source/Aura/Public/Interaction/EnemyInterface.h

@@ -0,0 +1,22 @@
+// Copyright; GhostPacket Games
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "UObject/Interface.h"
+#include "EnemyInterface.generated.h"
+
+UINTERFACE(MinimalAPI)
+class UEnemyInterface : public UInterface
+{
+	GENERATED_BODY()
+};
+
+class AURA_API IEnemyInterface
+{
+	GENERATED_BODY()
+
+public:
+	virtual void HighlightActor () = 0; // pure virtual function
+	virtual void UnHighlightActor () = 0;
+};

Source/Aura/Public/Player/AuraPlayerController.h

@@ -9,6 +9,8 @@
 class UInputMappingContext;
 class UInputAction;
 
+class IEnemyInterface;
+
 struct FInputActionValue;
 
 UCLASS()
@@ -18,6 +20,7 @@ class AURA_API AAuraPlayerController : public APlayerController
 
 public:
 	AAuraPlayerController ();
+	virtual void PlayerTick(float DeltaTime) override;
 
 protected:
 	virtual void BeginPlay() override;
@@ -31,4 +34,10 @@ private:
 	TObjectPtr<UInputAction> MoveAction;
 
 	void Move (const FInputActionValue &InputActionValue);
+
+	void CursorTrace ();
+
+	// for highlighting
+	TScriptInterface<IEnemyInterface> LastActor; // TScriptInterface must be used to hold interfaces
+	TScriptInterface<IEnemyInterface> ThisActor;
 };