Highlight Enemies

Source/Aura/Aura.h

@@ -4,3 +4,4 @@
 
 #include "CoreMinimal.h"
 
+#define CUSTOM_DEPTH_RED 250

Source/Aura/Private/Character/AuraEnemy.cpp

@@ -2,4 +2,27 @@
 
 
 #include "Character/AuraEnemy.h"
+#include "Aura/Aura.h"
 
+AAuraEnemy::AAuraEnemy()
+{
+	GetMesh()->SetCollisionResponseToChannel(ECC_Visibility, ECR_Block);
+
+	GetMesh()->SetRenderCustomDepth(false);
+	GetMesh()->SetCustomDepthStencilValue(CUSTOM_DEPTH_RED);
+
+	Weapon->SetRenderCustomDepth(false);
+	Weapon->SetCustomDepthStencilValue(CUSTOM_DEPTH_RED);
+}
+
+void AAuraEnemy::HighlightActor()
+{
+	GetMesh()->SetRenderCustomDepth(true);
+	Weapon->SetRenderCustomDepth(true);
+}
+
+void AAuraEnemy::UnHighlightActor()
+{
+	GetMesh()->SetRenderCustomDepth(false);
+	Weapon->SetRenderCustomDepth(false);
+}

Source/Aura/Private/Interaction/EnemyInterface.cpp

@@ -0,0 +1,7 @@
+// Assets provided by DruidMechanics. Copyright Jonathan Rampersad 2024
+
+
+#include "Interaction/EnemyInterface.h"
+
+
+// Add default functionality here for any IMyClass functions that are not pure virtual.

Source/Aura/Private/Player/AuraPlayerController.cpp

@@ -4,12 +4,20 @@
 #include "Player/AuraPlayerController.h"
 #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::BeginPlay()
 {
 	Super::BeginPlay();
@@ -52,3 +60,60 @@ void AAuraPlayerController::Move(const FInputActionValue& InputActionValue)
 	}
 }
 
+void AAuraPlayerController::CursorTrace()
+{
+	FHitResult CursorHit;
+	GetHitResultUnderCursor(ECC_Visibility, false, CursorHit);
+	if (!CursorHit.bBlockingHit) return;
+
+	LastActor = ThisActor;
+	ThisActor = CursorHit.GetActor();
+
+	/**
+	 * Line trace 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, and Highlight ThisActor
+	 *	E. Both actors are valid, and are the same actor
+	 *		- Do nothing
+	 */
+	if (LastActor == nullptr)
+	{
+		if (ThisActor != nullptr)
+		{
+			// Case B
+			ThisActor->HighlightActor();
+		}
+		else
+		{
+			// Case A - both are null, do nothing
+		}
+	}
+	else // LastActor is valid
+	{
+		if (ThisActor == nullptr)
+		{
+			// Case C
+			LastActor->UnHighlightActor();
+		}
+		else // both actors are valid
+		{
+			if (LastActor != ThisActor)
+			{
+				// Case D
+				LastActor->UnHighlightActor();
+				ThisActor->HighlightActor();
+			}
+			else
+			{
+				// Case E - do nothing
+			}
+		}
+	}
+}
+

Source/Aura/Public/Character/AuraEnemy.h

@@ -4,14 +4,19 @@
 
 #include "CoreMinimal.h"
 #include "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:
+	AAuraEnemy();
+	virtual void HighlightActor() override;
+	virtual void UnHighlightActor() override;
 };

Source/Aura/Public/Interaction/EnemyInterface.h

@@ -0,0 +1,27 @@
+// Assets provided by DruidMechanics. Copyright Jonathan Rampersad 2024
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "UObject/Interface.h"
+#include "EnemyInterface.generated.h"
+
+// This class does not need to be modified.
+UINTERFACE()
+class UEnemyInterface : public UInterface
+{
+	GENERATED_BODY()
+};
+
+/**
+ * 
+ */
+class AURA_API IEnemyInterface
+{
+	GENERATED_BODY()
+
+	// Add interface functions to this class. This is the class that will be inherited to implement this interface.
+public:
+	virtual void HighlightActor() = 0;
+	virtual void UnHighlightActor() = 0;
+};

Source/Aura/Public/Player/AuraPlayerController.h

@@ -9,6 +9,7 @@
 struct FInputActionValue;
 class UInputAction;
 class UInputMappingContext;
+class IEnemyInterface;
 
 /**
  * 
@@ -21,6 +22,8 @@ class AURA_API AAuraPlayerController : public APlayerController
 public:
 	AAuraPlayerController();
 
+	virtual void PlayerTick(float DeltaTime) override;
+
 protected:
 	virtual void BeginPlay() override;
 
@@ -34,4 +37,8 @@ private:
 	TObjectPtr<UInputAction> MoveAction;
 
 	void Move(const FInputActionValue& InputActionValue);
+
+	void CursorTrace();
+	TScriptInterface<IEnemyInterface> LastActor;
+	TScriptInterface<IEnemyInterface> ThisActor;
 };