Section 15: AI and Behavior Trees - Lecture 310

Retargeting New Montages

Source/Shooter/Enemy.cpp

@@ -15,6 +15,7 @@
 #include "ShooterCharacter.h"
 #include "Components/BoxComponent.h"
 #include "Components/CapsuleComponent.h"
+#include "Engine/SkeletalMeshSocket.h"
 
 // Sets default values
 AEnemy::AEnemy() :
@@ -31,7 +32,13 @@ AEnemy::AEnemy() :
 	AttackRFast(TEXT("AttackRFast")),
 	AttackL(TEXT("AttackL")),
 	AttackR(TEXT("AttackR")),
-	BaseDamage(20.f)
+	BaseDamage(20.f),
+	LeftWeaponSocket(TEXT("FX_Trail_L_02")),
+	RightWeaponSocket(TEXT("FX_Trail_R_02")),
+	bCanAttack(true),
+	AttackWaitTime(1.f),
+	bDying(false),
+	DeathTime(4.f)
 {
  	// Set this character to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
 	PrimaryActorTick.bCanEverTick = true;
@@ -83,11 +90,16 @@ void AEnemy::BeginPlay()
 	// Get the AI Controller
 	EnemyController = Cast<AEnemyController>(GetController());
 
+	if (EnemyController)
+	{
+		EnemyController->GetBlackboardComponent()->SetValueAsBool(TEXT("CanAttack"), true);
+	}
+	
 	const FVector WorldPatrolPoint = UKismetMathLibrary::TransformLocation(GetActorTransform(), PatrolPoint);
-	DrawDebugSphere(GetWorld(), WorldPatrolPoint, 25.f, 12, FColor::Red, true);
+	//DrawDebugSphere(GetWorld(), WorldPatrolPoint, 25.f, 12, FColor::Red, true);
 
 	const FVector WorldPatrolPoint2 = UKismetMathLibrary::TransformLocation(GetActorTransform(), PatrolPoint2);
-	DrawDebugSphere(GetWorld(), WorldPatrolPoint2, 25.f, 12, FColor::Blue, true);
+	//DrawDebugSphere(GetWorld(), WorldPatrolPoint2, 25.f, 12, FColor::Blue, true);
 	
 	if (EnemyController)
 	{
@@ -105,7 +117,34 @@ void AEnemy::ShowHealthBar_Implementation()
 
 void AEnemy::Die()
 {
+	if (bDying) return;
+	bDying = true;
+	
 	HideHealthBar();
+
+	if (EnemyController)
+	{
+		EnemyController->GetBlackboardComponent()->SetValueAsBool("Dead", true);
+		EnemyController->StopMovement();
+	}
+	
+	if (!DeathMontage) return;
+	
+	UAnimInstance* AnimInstance = GetMesh()->GetAnimInstance();
+	if (!AnimInstance) return;
+
+	AnimInstance->Montage_Play(DeathMontage);
+}
+
+void AEnemy::FinishDeath()
+{
+	GetMesh()->bPauseAnims = true;
+	GetWorldTimerManager().SetTimer(DeathTimer, this, &AEnemy::DestroyEnemy, DeathTime);
+}
+
+void AEnemy::DestroyEnemy()
+{
+	Destroy();
 }
 
 void AEnemy::PlayHitMontage(FName Section, float PlayRate)
@@ -188,7 +227,7 @@ void AEnemy::CombatRangeOverlap(UPrimitiveComponent* OverlappedComponent, AActor
 	
 	if (!EnemyController) return;
 	EnemyController->GetBlackboardComponent()->SetValueAsBool(TEXT("InAttackRange"), true);
-	UE_LOG(LogTemp, Warning, TEXT("overlap player"));
+	//UE_LOG(LogTemp, Warning, TEXT("overlap player"));
 }
 
 void AEnemy::CombatRangeEndOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
@@ -201,7 +240,7 @@ void AEnemy::CombatRangeEndOverlap(UPrimitiveComponent* OverlappedComponent, AAc
 	
 	if (!EnemyController) return;
 	EnemyController->GetBlackboardComponent()->SetValueAsBool(TEXT("InAttackRange"), false);
-	UE_LOG(LogTemp, Warning, TEXT("end overlap player"));
+	//UE_LOG(LogTemp, Warning, TEXT("end overlap player"));
 }
 
 void AEnemy::PlayAttackMontage(FName Section, float PlayRate)
@@ -212,6 +251,12 @@ void AEnemy::PlayAttackMontage(FName Section, float PlayRate)
 		AnimInstance->Montage_Play(AttackMontage, PlayRate);
 		AnimInstance->Montage_JumpToSection(Section, AttackMontage);
 	}
+	bCanAttack = false;
+	GetWorldTimerManager().SetTimer(AttackWaitTimer, this, &AEnemy::ResetCanAttack, AttackWaitTime);
+	if (EnemyController)
+	{
+		EnemyController->GetBlackboardComponent()->SetValueAsBool(TEXT("CanAttack"), false);
+	}
 }
 
 FName AEnemy::GetAttackSectionName() const
@@ -231,29 +276,73 @@ FName AEnemy::GetAttackSectionName() const
 	}
 }
 
-void AEnemy::DoDamage(AActor* Victim)
+void AEnemy::DoDamage(AShooterCharacter* Victim)
 {
 	if (!Victim) return;
-	if (auto const Character = Cast<AShooterCharacter>(Victim))
-	{
-		UGameplayStatics::ApplyDamage(Character, BaseDamage, EnemyController, this, UDamageType::StaticClass());
-		if (USoundCue* MeleeImpactSound = Character->GetMeleeImpactSound())
+	
+	UGameplayStatics::ApplyDamage(Victim, BaseDamage, EnemyController, this, UDamageType::StaticClass());
+	if (USoundCue* MeleeImpactSound = Victim->GetMeleeImpactSound())
 	{
 	    UGameplayStatics::PlaySoundAtLocation(this, MeleeImpactSound, GetActorLocation());
 	}
+}
+
+void AEnemy::SpawnBlood(AShooterCharacter* Victim, FName WeaponSocket)
+{
+	if (!Victim) return;
+	
+	UParticleSystem* Particles = Victim->GetBloodParticles();
+	if (!Particles) return;
+	
+	const USkeletalMeshSocket* TipSocket{ GetMesh()->GetSocketByName(WeaponSocket) };
+	if (!TipSocket) return;
+	
+	const FTransform SocketTransform{ TipSocket->GetSocketTransform(GetMesh()) };
+	UGameplayStatics::SpawnEmitterAtLocation(GetWorld(), Particles, SocketTransform);
+}
+
+void AEnemy::StunCharacter(AShooterCharacter* Victim)
+{
+	if (!Victim) return;
+
+	const float Stun{ FMath::RandRange(0.f,1.f) };
+
+	if (Stun <= Victim->GetStunChance())
+	{
+		Victim->Stun();
 	}
 }
 
+void AEnemy::ResetCanAttack()
+{
+	bCanAttack = true;
+
+	if (!EnemyController) return;
+	EnemyController->GetBlackboardComponent()->SetValueAsBool(TEXT("CanAttack"), true);
+}
+
 void AEnemy::OnLeftWeaponOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
                                  UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
 {
-	DoDamage(OtherActor);
+	auto const Character = Cast<AShooterCharacter>(OtherActor);
+	if (Character)
+	{
+		DoDamage(Character);
+		SpawnBlood(Character, LeftWeaponSocket);
+		StunCharacter(Character);
+	}
 }
 
 void AEnemy::OnRightWeaponOverlap(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
 	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
 {
-	DoDamage(OtherActor);
+	auto const Character = Cast<AShooterCharacter>(OtherActor);
+	if (Character)
+	{
+		DoDamage(Character);
+		SpawnBlood(Character, RightWeaponSocket);
+		StunCharacter(Character);
+	}
 }
 
 void AEnemy::ActivateLeftWeapon()
@@ -303,6 +392,8 @@ void AEnemy::BulletHit_Implementation(FHitResult HitResult)
 		UGameplayStatics::SpawnEmitterAtLocation(GetWorld(), ImpactParticles, HitResult.Location, FRotator(0.f), true);
 	}
 
+	if (bDying) return;
+	
 	ShowHealthBar();
 
 	// Determine whether bullet hit stuns
@@ -318,6 +409,12 @@ void AEnemy::BulletHit_Implementation(FHitResult HitResult)
 float AEnemy::TakeDamage(float DamageAmount, FDamageEvent const& DamageEvent, AController* EventInstigator,
 	AActor* DamageCauser)
 {
+	// Set the Target blackboard key to aggro the character
+	if (EnemyController)
+	{
+		EnemyController->GetBlackboardComponent()->SetValueAsObject(FName("Target"), DamageCauser);
+	}
+	
 	float DamageInflicted = DamageAmount;
 	if (Health - DamageAmount <= 0.f)
 	{

Source/Shooter/Enemy.h

@@ -14,6 +14,7 @@ class UBehaviorTree;
 class AEnemyController;
 class USphereComponent;
 class UBoxComponent;
+class AShooterCharacter;
 
 UCLASS()
 class SHOOTER_API AEnemy : public ACharacter, public IBulletHitInterface
@@ -99,7 +100,18 @@ protected:
 	UFUNCTION(BlueprintCallable)
 	void DeactivateRightWeapon();
 
-	void DoDamage(AActor* Victim);
+	void DoDamage(AShooterCharacter* Victim);
+	void SpawnBlood(AShooterCharacter* Victim, FName WeaponSocket);
+
+	// Attemp to stun character
+	void StunCharacter(AShooterCharacter* Victim);
+
+	void ResetCanAttack();
+
+	UFUNCTION(BlueprintCallable)
+	void FinishDeath();
+
+	void DestroyEnemy();
 private:
 	/** Particles to spawn when hit by bullets */
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
@@ -202,6 +214,34 @@ private:
 
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
 	float BaseDamage;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	FName LeftWeaponSocket;
+	
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	FName RightWeaponSocket;
+
+	/** True when Enemy can attack */
+	UPROPERTY(VisibleAnywhere, Category = Combat, meta = (AllowPrivateAccess = true))
+	bool bCanAttack;
+
+	FTimerHandle AttackWaitTimer;
+
+	/** Min wait time between attacks */
+	UPROPERTY(EditAnywhere, Category = Combat, meta = (AllowPrivateAccess = true))
+	float AttackWaitTime;
+	
+	/** Death anim montage */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	UAnimMontage* DeathMontage;
+
+	bool bDying;
+
+	FTimerHandle DeathTimer;
+
+	/** Time after death until Destroy */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	float DeathTime;
 public:	
 	// Called every frame
 	virtual void Tick(float DeltaTime) override;

Source/Shooter/ShooterCharacter.cpp

@@ -18,6 +18,8 @@
 #include "BulletHitInterface.h"
 #include "Enemy.h"
 #include "PhysicalMaterials/PhysicalMaterial.h"
+#include "EnemyController.h"
+#include "BehaviorTree/BlackboardComponent.h"
 
 // Sets default values
 AShooterCharacter::AShooterCharacter() :
@@ -79,7 +81,8 @@ AShooterCharacter::AShooterCharacter() :
 	// Icon animation property
 	HighlightedSlot(-1),
 	Health(100.f),
-	MaxHealth(100.f)
+	MaxHealth(100.f),
+	StunChance(.25f)
 {
  	// Set this character to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
 	PrimaryActorTick.bCanEverTick = true;
@@ -212,7 +215,13 @@ float AShooterCharacter::TakeDamage(float DamageAmount, FDamageEvent const& Dama
 	{
 		DamageInflicted = Health; 
 		Health = 0.f;
-		//Die();
+		Die();
+
+		auto EnemyController = Cast<AEnemyController>(EventInstigator);
+		if (EnemyController)
+		{
+			EnemyController->GetBlackboardComponent()->SetValueAsBool(FName("CharacterDead"), true);
+		}
 	}
 	else
 	{
@@ -221,6 +230,26 @@ float AShooterCharacter::TakeDamage(float DamageAmount, FDamageEvent const& Dama
 	return DamageInflicted;
 }
 
+void AShooterCharacter::Die()
+{
+	if (!DeathMontage) return;
+	
+	UAnimInstance* AnimInstance = GetMesh()->GetAnimInstance();
+	if (!AnimInstance) return;
+
+	AnimInstance->Montage_Play(DeathMontage);
+}
+
+void AShooterCharacter::FinishDeath()
+{
+	GetMesh()->bPauseAnims = true;
+	APlayerController* PC = UGameplayStatics::GetPlayerController(this, 0);
+	if (PC)
+	{
+		DisableInput(PC);
+	}
+}
+
 // Called every frame
 void AShooterCharacter::Tick(float DeltaTime)
 {
@@ -309,7 +338,9 @@ void AShooterCharacter::LookUp(float Value)
 void AShooterCharacter::AimingButtonPressed()
 {
 	bAimingButtonPressed = true;
-	if (CombatState != ECombatState::ECS_Reloading && CombatState != ECombatState::ECS_Equipping)
+	if (CombatState != ECombatState::ECS_Reloading &&
+		CombatState != ECombatState::ECS_Equipping &&
+		CombatState != ECombatState::ECS_Stunned)
 	{
 		Aim();
 	}
@@ -504,6 +535,16 @@ EPhysicalSurface AShooterCharacter::GetSurfaceType()
 	return UPhysicalMaterial::DetermineSurfaceType(HitResult.PhysMaterial.Get());
 }
 
+void AShooterCharacter::EndStun()
+{
+	CombatState = ECombatState::ECS_Unoccupied;
+
+	if (bAimingButtonPressed)
+	{
+		Aim();
+	}
+}
+
 void AShooterCharacter::UnhighlightInventorySlot()
 {
 	if (HighlightedSlot != -1)
@@ -513,6 +554,19 @@ void AShooterCharacter::UnhighlightInventorySlot()
 	}
 }
 
+void AShooterCharacter::Stun()
+{
+	if (Health <= 0.f) return;
+	if (!HitReactMontage) return;
+	
+	UAnimInstance* AnimInstance = GetMesh()->GetAnimInstance();
+	if (!AnimInstance) return;
+	
+	CombatState = ECombatState::ECS_Stunned;
+
+	AnimInstance->Montage_Play(HitReactMontage);
+}
+
 int32 AShooterCharacter::GetInterpLocationIndex()
 {
 	int32 LowestIndex = 1;
@@ -632,6 +686,7 @@ void AShooterCharacter::StartFireTimer()
 void AShooterCharacter::AutoFireReset()
 {
 	if (!EquippedWeapon) return;
+	if (CombatState == ECombatState::ECS_Stunned) return;
 	
 	CombatState = ECombatState::ECS_Unoccupied;
 
@@ -1135,6 +1190,7 @@ void AShooterCharacter::ReloadWeapon()
 void AShooterCharacter::FinishReloading()
 {
 	if (!EquippedWeapon) return;
+	if (CombatState == ECombatState::ECS_Stunned) return;
 
 	CombatState = ECombatState::ECS_Unoccupied;
 
@@ -1175,6 +1231,8 @@ void AShooterCharacter::FinishReloading()
 
 void AShooterCharacter::FinishEquipping()
 {
+	if (CombatState == ECombatState::ECS_Stunned) return;
+
 	CombatState = ECombatState::ECS_Unoccupied;
 
 	if (bAimingButtonPressed)

Source/Shooter/ShooterCharacter.h

@@ -25,6 +25,7 @@ enum class ECombatState : uint8
 	ECS_FireTimerInProgress UMETA(DisplayName = "FireTimerInProgress"),
 	ECS_Reloading			UMETA(DisplayName = "Reloading"),
 	ECS_Equipping			UMETA(DisplayName = "Equipping"),
+	ECS_Stunned				UMETA(DisplayName = "Stunned"),
 	
 	ECS_MAX					UMETA(DisplayName = "DefaultMax")
 };
@@ -221,6 +222,13 @@ protected:
 	UFUNCTION(BlueprintCallable)
 	EPhysicalSurface GetSurfaceType();
 
+	UFUNCTION(BlueprintCallable)
+	void EndStun();
+
+	void Die();
+
+	UFUNCTION(BlueprintCallable)
+	void FinishDeath();
 private:
 	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Camera, meta = (AllowPrivateAccess = true))
 	USpringArmComponent* CameraBoom;
@@ -500,6 +508,22 @@ private:
 	/** Sound made when character gets hit by a melee attack */
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
 	USoundCue* MeleeImpactSound;
+
+	/** Blood splatter particles for melee hit */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	UParticleSystem* BloodParticles;
+
+	/** Hit react anim montage; for when the character is stunned */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	UAnimMontage* HitReactMontage;
+
+	/** Chance of being stunned when hit by an enemy */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	float StunChance;
+	
+	/** Character death anim montage */
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Combat, meta = (AllowPrivateAccess = true))
+	UAnimMontage* DeathMontage;
 public:
 	/* Returns CameraBoom SubObject */
 	FORCEINLINE USpringArmComponent* GetCameraBoom() const { return CameraBoom; }
@@ -557,4 +581,8 @@ public:
 	float GetMaxHealth() const	{ return MaxHealth; }
 
 	FORCEINLINE USoundCue* GetMeleeImpactSound() const { return MeleeImpactSound; }
+	FORCEINLINE	UParticleSystem* GetBloodParticles() const { return BloodParticles; }
+
+	void Stun();
+	FORCEINLINE float GetStunChance() const { return StunChance; }
 };