Unreal Engine C++ Pro

This skill provides expert-level guidelines for developing with Unreal Engine 5 using C++. It focuses on writing robust, performant, and standard-compliant code.

When to Use

Use this skill when:

Developing C++ code for Unreal Engine 5.x projects
Writing Actors, Components, or UObject-derived classes
Optimizing performance-critical code in Unreal Engine
Debugging memory leaks or garbage collection issues
Implementing Blueprint-exposed functionality
Following Epic Games' coding standards and conventions
Working with Unreal's reflection system (UCLASS, USTRUCT, UFUNCTION)
Managing asset loading and soft references

Do not use this skill when:

Working with Blueprint-only projects (no C++ code)
Developing for Unreal Engine versions prior to 5.x
Working on non-Unreal game engines
The task is unrelated to Unreal Engine development

Core Principles

UObject & Garbage Collection:
- Always use
```
UPROPERTY()
```
  for
```
UObject*
```
  member variables to ensure they are tracked by the Garbage Collector (GC).
- Use
```
TStrongObjectPtr<>
```
  if you need to keep a root reference outside of a UObject graph, but prefer
```
addToRoot()
```
  generally.
- Understand the
```
IsValid()
```
  check vs
```
nullptr
```
  .
```
IsValid()
```
  handles pending kill state safely.
Unreal Reflection System:
- Use
```
UCLASS()
```
  ,
```
USTRUCT()
```
  ,
```
UENUM()
```
  ,
```
UFUNCTION()
```
  to expose types to the reflection system and Blueprints.
- Minimize
```
BlueprintReadWrite
```
  when possible; prefer
```
BlueprintReadOnly
```
  for state that shouldn't be trampled by logic in UI/Level BPs.
Performance First:
- Tick: Disable Ticking (
```
bCanEverTick = false
```
  ) by default. Only enable it if absolutely necessary. Prefer timers (
```
GetWorldTimerManager()
```
  ) or event-driven logic.
- Casting: Avoid
```
Cast<T>()
```
  in hot loops. Cache references in
```
BeginPlay
```
  .
- Structs vs Classes: Use
```
F
```
  structs for data-heavy, non-UObject types to reduce overhead.

Naming Conventions (Strict)

Follow Epic Games' coding standard:

Templates: Prefix with
```
T
```
(e.g.,
```
TArray
```
,
```
TMap
```
).
UObject: Prefix with
```
U
```
(e.g.,
```
UCharacterMovementComponent
```
).
AActor: Prefix with
```
A
```
(e.g.,
```
AMyGameMode
```
).
SWidget: Prefix with
```
S
```
(Slate widgets).
Structs: Prefix with
```
F
```
(e.g.,
```
FVector
```
).
Enums: Prefix with
```
E
```
(e.g.,
```
EWeaponState
```
).
Interfaces: Prefix with
```
I
```
(e.g.,
```
IInteractable
```
).
Booleans: Prefix with
```
b
```
(e.g.,
```
bIsDead
```
).

Common Patterns

1. Robust Component Lookup

Avoid

GetComponentByClass

Tick

. Do it in

PostInitializeComponents

BeginPlay

cpp

void AMyCharacter::PostInitializeComponents() {
    Super::PostInitializeComponents();
    HealthComp = FindComponentByClass<UHealthComponent>();
    check(HealthComp); // Fail hard in dev if missing
}

2. Interface Implementation

Use interfaces to decouple systems (e.g., Interaction system).

cpp

// Interface call check
if (TargetActor->Implements<UInteractable>()) {
    IInteractable::Execute_OnInteract(TargetActor, this);
}

3. Async Loading (Soft References)

Avoid hard references (

UPROPERTY(EditDefaultsOnly) TSubclassOf<AActor>

) for massive assets which force load orders. Use

TSoftClassPtr

TSoftObjectPtr

cpp

UPROPERTY(EditAnywhere, BlueprintReadWrite)
TSoftClassPtr<AWeapon> WeaponClassToLoad;

void AMyCharacter::Equip() {
    if (WeaponClassToLoad.IsPending()) {
        WeaponClassToLoad.LoadSynchronous(); // Or use StreamableManager for async
    }
}

Debugging

Logging: Use

UE_LOG

with custom categories.

cpp

DEFINE_LOG_CATEGORY_STATIC(LogMyGame, Log, All);
UE_LOG(LogMyGame, Warning, TEXT("Health is low: %f"), CurrentHealth);

Screen Messages:

cpp

if (GEngine) GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Died!"));

Visual Logger: extremely useful for AI debugging. Implement
```
IVisualLoggerDebugSnapshotInterface
```
.

Checklist before PR

Does this Actor need to Tick? Can it be a Timer?
Are all
```
UObject*
```
members wrapped in
```
UPROPERTY
```
?
Are hard references (TSubclassOf) causing load chains? Can they be Soft Ptrs?
Did you clean up verified delegates in
```
EndPlay
```
?

unreal-engine-cpp-pro

NPX Install

Tags

SKILL.md Content