Mastering Unreal Engine for Mobile Idle RPGs: Building an Advanced Automated Combat System Like Genshin Impact

Introduction

In mobile RPGs like Genshin Impact, the allure of automated combat lies in its accessibility and immersive experience. Players are drawn to the convenience of idle combat systems, which enhance engagement and extend playtime without requiring constant input. This guide will walk through the creation of a sophisticated automated combat system in Unreal Engine, ideal for mobile idle RPGs. This system will feature AI-driven decision-making, modular combat routines, and customizable actions that mimic the precision and responsiveness of games like Genshin Impact.

Why a Robust Automated Combat System is Essential in Mobile RPGs

Idle RPGs thrive on the concept of “play while idle,” offering an engaging experience without demanding constant attention. Building a strong automated combat system in Unreal Engine can significantly boost player retention by allowing users to enjoy progression while they’re offline. This guide will provide game developers with a powerful, reusable combat framework that can fit into almost any RPG project, enabling customized actions, real-time decision-making, and seamless movement control.

Key Components of the Automated Combat System

To create a functional and scalable combat system, we’ll break the implementation into critical parts:

1. Enemy Targeting: Identify and select the most relevant target for the character.
2. Dynamic Movement: Efficiently move towards or away from enemies, maintaining optimal attack distance.
3. Combat Execution: Automatically perform actions such as attacks or special skills.
4. AI Decision Logic: Adapt decisions based on health, distance, enemy type, and other dynamic factors.

Step-By-Step Guide to Building an Automated Combat System in Unreal Engine

Below is a complete, high-quality code and framework designed to help you build an automated combat system ready for mobile idle RPGs. We’ll walk through each step, focusing on Unreal’s Blueprint and C++ modules for maximum efficiency and performance.

Step 1: Implementing Enemy Targeting

The AI selects the closest target, continually updating to ensure the optimal enemy is engaged. This approach guarantees the character can switch targets as needed, keeping players engaged even with varied enemy types.

// TargetSelector.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "TargetSelector.generated.h"

UCLASS()
class YOURGAME_API ATargetSelector : public AActor
{
    GENERATED_BODY()
    
public:    
    ATargetSelector();
    AActor* GetClosestTarget(TArray<AActor*> Enemies);

private:
    AActor* CurrentTarget;
};

// TargetSelector.cpp
#include "TargetSelector.h"
#include "Kismet/KismetMathLibrary.h"

ATargetSelector::ATargetSelector()
{
    PrimaryActorTick.bCanEverTick = true;
}

AActor* ATargetSelector::GetClosestTarget(TArray<AActor*> Enemies)
{
    float MinDistance = FLT_MAX;
    CurrentTarget = nullptr;

    for (AActor* Enemy : Enemies)
    {
        float Distance = FVector::Dist(this->GetActorLocation(), Enemy->GetActorLocation());
        if (Distance < MinDistance)
        {
            MinDistance = Distance;
            CurrentTarget = Enemy;
        }
    }
    return CurrentTarget;
}

Step 2: Dynamic Movement Toward Target

Using Unreal’s NavMesh, the player character moves toward the target, stopping within the defined attack range. This keeps the character consistently within an ideal position to attack.

// AutoMovementComponent.h
#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "AutoMovementComponent.generated.h"

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class YOURGAME_API UAutoMovementComponent : public UActorComponent
{
    GENERATED_BODY()

public:    
    UAutoMovementComponent();
    void MoveToTarget(AActor* Target);

private:
    float StoppingDistance;
};

// AutoMovementComponent.cpp
#include "AutoMovementComponent.h"
#include "AIController.h"

UAutoMovementComponent::UAutoMovementComponent()
{
    PrimaryComponentTick.bCanEverTick = true;
    StoppingDistance = 200.0f; // Define optimal stopping distance
}

void UAutoMovementComponent::MoveToTarget(AActor* Target)
{
    if (AAIController* AIController = Cast<AAIController>(GetOwner()->GetController()))
    {
        AIController->MoveToActor(Target, StoppingDistance, true, true, true, 0, true);
    }
}

Step 3: Combat Execution – Attacks and Abilities

Automatically perform attacks with cooldown logic and conditions, providing flexibility for additional combat actions such as skills or special moves.

// AutoCombatComponent.h
#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "AutoCombatComponent.generated.h"

UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
class YOURGAME_API UAutoCombatComponent : public UActorComponent
{
    GENERATED_BODY()

public:
    UAutoCombatComponent();
    void ExecuteAttack(AActor* Target);

private:
    float AttackCooldown;
    float LastAttackTime;
};

// AutoCombatComponent.cpp
#include "AutoCombatComponent.h"

UAutoCombatComponent::UAutoCombatComponent()
{
    PrimaryComponentTick.bCanEverTick = true;
    AttackCooldown = 1.5f;
    LastAttackTime = -AttackCooldown;
}

void UAutoCombatComponent::ExecuteAttack(AActor* Target)
{
    if (Target && (GetWorld()->TimeSeconds - LastAttackTime) >= AttackCooldown)
    {
        LastAttackTime = GetWorld()->TimeSeconds;
        // Execute attack logic here
        UE_LOG(LogTemp, Log, TEXT("Attacking target: %s"), *Target->GetName());
    }
}

Step 4: Decision-Making Logic – Adaptive Combat AI

A robust AI system to adaptively determine actions based on conditions like health or proximity to the target. This includes the flexibility to engage or retreat based on conditions, enhancing immersion and strategy.

// CombatAIComponent.h
#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "CombatAIComponent.generated.h"

UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
class YOURGAME_API UCombatAIComponent : public UActorComponent
{
    GENERATED_BODY()

public:
    UCombatAIComponent();
    void EvaluateCombatState();

private:
    float HealthThreshold;
    bool bShouldRetreat;
};

// CombatAIComponent.cpp
#include "CombatAIComponent.h"

UCombatAIComponent::UCombatAIComponent()
{
    PrimaryComponentTick.bCanEverTick = true;
    HealthThreshold = 0.3f;
    bShouldRetreat = false;
}

void UCombatAIComponent::EvaluateCombatState()
{
    float CurrentHealth = 0.8f; // Placeholder for actual health retrieval logic

    if (CurrentHealth < HealthThreshold)
    {
        bShouldRetreat = true;
        // Trigger retreat logic here
    }
    else
    {
        bShouldRetreat = false;
    }
}

Advantages and Limitations of Automated Combat Systems

Advantages:

• Efficient Engagement: Players can enjoy hands-free combat, improving convenience and retention.
• High Modularity: This system can be easily customized and expanded with additional AI behaviors.
• Adaptability: Modular code structure means it can be used across multiple games with minor adjustments.

Limitations:

• Complex AI Balancing: Adjusting AI behaviors to avoid repetitive actions requires thorough testing.
• Reduced Interactivity: Fully automated systems can reduce skill-based gameplay, potentially affecting player engagement in the long term.

Conclusion

Building a sophisticated automated combat system in Unreal Engine for mobile idle RPGs like Genshin Impact provides the foundation for a captivating, hands-free gameplay experience. This guide’s modular approach allows for adaptable, reusable code that can serve as the basis for any idle RPG’s combat system, enabling streamlined engagement while preserving player immersion.