Combat

20 July, 2020

1 minute read

Melee

Attacks(for now) are very basic melee attacks with Swords, Maces and Axes. Attacks are performed when the Player presses the LMB.

Once the LMB is pressed, a check is done to see if the Player is not performing any other action at that time. If not, MeleeAttack() is called.

MeleeAttack() sets up the Character for attacks(Resets the IdleTimer, increments the AttackComboSection(Used for Combo Attacks)) and then calls PlayMeleeAttack().

MeleeAttack()

void AMain::MeleeAttack()
{
	ResetIdleTimer();

	if (!bAttacking && (MovementStatus != EMovementStatus::EMS_Dead))
	{
		bAttacking = true;

		SetInterpToEnemy(true);

		/** AttackSection
		 *  == 0 OR 1 -> Normal Attack
		 *  == 2 -> Combo Attack
		*/
		PlayMeleeAttack((AttackComboSection++) % NumberOfMeleeAttacks);
	}
}

PlayMeleeAttack() is responsible for using AttackComboSection to pick a particular animation out of the attack animations located in an Anim Montage called CombatMontage.

PlayMeleeAttack()

void AMain::PlayMeleeAttack(int32 Section)
{
	UAnimInstance* AnimInstance = GetMesh()->GetAnimInstance();


	// Attack Sections start from 1
	Section += 1;


	if (AnimInstance && CombatMontage)
	{
		// Used for Enemy Hit Reaction
		if (EquippedWeapon)EquippedWeapon->MainAttackSection = Section;


		FString AttackName;

		// Append Section number

		// If attack is using a weapon
		if (bIsWeaponDrawn)
		{
			if (EquippedWeapon->bIsTwoHanded)AttackName.Append("TwoHandedAttack_");
			else AttackName.Append("OneHandedAttack_");

			if (!bCrouched)
			{
				// Get a random Final Combo Attack (Ranges from Attack_3 to Attack_5)
				if (Section == 3)Section += FMath::RandRange(0, NumberOfMeleeComboAttacks);
			}
			else
			{	// Only one Section for crouched attacks
				Section = 1;
				AttackName.Append("Crouched_");
			}
		}

		// else if melee attack
		else
		{
			// If Player has a Shield equipped, play the even-numbered attacks(right-handed attacks) only.
			if (PlayerStatus == EPlayerStatus::EPS_ShieldUnarmed)
			{
				// Override Section  todo Find a better way to find the even AttackSection
				Section = FMath::RandRange(2, 4);
				if (Section % 2)Section -= 1;	// Set Section to play the 2nd Animation if RandRange returns 3.
			}

			AttackName.Append("MeleeAttack_");
		}

		AttackName.AppendInt(Section);

		UE_LOG(LogTemp, Warning, TEXT("Attack = %s"), *AttackName);

		// Play Montage
		AnimInstance->Montage_Play(CombatMontage, 1.0f);
		AnimInstance->Montage_JumpToSection(*AttackName, CombatMontage);
	}
}

After the attack ends, MeleeAttackEnd() checks if the Player is still holding LMB down. If they are, Attack() will be called again. If not, the Character will be restored to its normal state and will not be ready to attack.

MeleeAttackEnd()

void AMain::MeleeAttackEnd()
{
	bAttacking = false;

	SetInterpToEnemy(false);

	// Reset Swing Sound index
	SwingSoundIndex = 0;

	// Reset Combo Attack Section if Player does not press LMB within AttackComboSectionResetTime.
	GetWorldTimerManager().SetTimer(AttackTimerHandle, this, &AMain::ResetMeleeAttackComboSection, AttackComboSectionResetTime);

	// If Player is still holding LMBDown, attack again.
	if (bLMBDown)
	{
		GetWorldTimerManager().ClearTimer(AttackTimerHandle);
		MeleeAttack();
	}
}

Weapons

Following is one of the Weapons used in the game.

The CombatCollision BoxCollision on the Weapon is used to check if the Weapon has hit an Enemy during an attack, very similar to the CombatCollision on the Enemies.

Checking for Hits

Anim Notifies are used in the attack animations to call functions during the attacks.

There are 4 main Anim Notifies used in attack animations:

ActivateCollision: Activates CombatCollision to check for overlaps during the attack.
DeactivateCollision: Deactivates CombatCollision after the attack has finished.
SwingSound: Plays a sword swoosh sound.
AttackEnd: Calls AttackEnd().

If an overlap is detected by CombatCollision during an attack, its OnOverlapBegin() function gets called.

CombatOnOverlapBegin()

void AWeapon::CombatOnOverlapBegin(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor,
                                   UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep,
                                   const FHitResult& SweepResult)
{
	if (OtherActor)
	{
		AEnemy* Enemy = Cast<AEnemy>(OtherActor);

		// If OtherActor is an Enemy
		if (Enemy)
		{
			// Deactivate CombatCollisions of the Enemy in case their attack was interrupted
			Enemy->DeactivateCollisionLeft();
			Enemy->DeactivateCollisionRight();

			Enemy->AttackEnd();

			//Play Enemy Impact Animation
			Enemy->Impact(MainAttackSection);

			if (Enemy->HitParticles)
			{
				const USkeletalMeshSocket* WeaponSocket = SkeletalMesh->GetSocketByName("WeaponSocket");

				if (WeaponSocket)
				{
					FVector SocketLocation = WeaponSocket->GetSocketLocation(SkeletalMesh);

					// Spawn a particle effect at WeaponSocket
					UGameplayStatics::SpawnEmitterAtLocation(GetWorld(), Enemy->HitParticles, SocketLocation,
					                                         FRotator(0.0f), true);
				}
			}
			if (Enemy->HitSound)
			{
				UGameplayStatics::PlaySound2D(this, Enemy->HitSound);
			}
			// Inflict damage on the Enemy
			if (DamageTypeClass)
			{
				UGameplayStatics::ApplyDamage(Enemy, Damage, WeaponInstigator, this, DamageTypeClass);
			}
		}
	}
}

The above function inflicts damage on the Enemy that the CombatCollision overlaps with, along with emitting particle effects and impact sounds.

Attacks still have some minor bugs that will be fixed soon(example being the occasional incident of attacks registering twice on Enemies).

Am seeing ways on making the combat more interesting. One option is adding powers to stun Enemies or to dodge their attacks.

You can view the code of the project here!

In Action

While Unarmed and not in Combat Mode
While Unarmed and in Combat Mode

By Gokul Viswanath
Built with Gatsby