UE4 Code Snippets

.UE4 Code Snippets

Code and things.

Blueprint Tagging

// See Property Specified docs
// @link https://docs.unrealengine.com/latest/INT/Programming/UnrealArchitecture/Reference/Properties/Specifiers/index.html

// Property: Editable, read/write via blueprint, category member
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Forces")
FVector CenterOfMass;

// Function: Callable in Blueprint, category member
UFUNCTION(BlueprintCallable, Category = "Game|Components|ProjectileMovement")
void AddInputMove(FVector input);

// Property: Readonly in Blueprint (can't be removed). Visible only in archetypes.
UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly, Category = Vehicle)
class UMovementComponent* VehicleMovement;

Debug Widgets

// Onscreen message
GEngine->AddOnScreenDebugMessage(-1, fLifespan, FColor::Red, TEXT("Hello, I am annoying."));

// Draw a line
DrawDebugLine(GetWorld(), FVectorStart, FVectorTarget, FColor::Red, false, 0.1f, 0, fLifespan);

// Draw a sphere
DrawDebugSphere(GetWorld(), GetActorLocation(), fRadius, 16, FColor::Red, false, fLifespan);

Logging

/** Header */
DECLARE_LOG_CATEGORY_EXTERN(MyLogCat, Log, All);
 
/** Cpp file */
DEFINE_LOG_CATEGORY(MyLogCat);

/** Cpp */
UE_LOG(MyLogCat, Warning, TEXT("target rot p %f r %f y %f"), targetRot.Pitch, targetRot.Roll, targetRot.Yaw);

Physics and Forces

// Location specific force
UPrimitiveComponent* BasePrimComp = Cast<UPrimitiveComponent>(AttachParent);
BasePrimComp->AddForceAtLocation(WorldForce, GetComponentLocation(), NAME_None);

// Impulse
const FVector Impulse = FVector(0.f, 0.f, JumpImpulse);
BasePrimComp->AddImpulse(Impulse);

// Torque
const FVector Torque = FVector(0.f, 0.f, 1.0f);
BasePrimComp->AddTorque(Torque);

Property Types

// Standard
bool myBoolean = true;
int32 myInt = 1;
float myFloat = 1.f;
FString myString = TEXT("Hello World");

// Struct-type
FVector myVector = FVector(1.f, 0.f, 0.1f);
FVector2D myVector2d = FVector2D(1.f, 2.f);
FRotator myRotator = FRotator(1.f, 2.f, 3.f);
FColor myColor = FColor(255, 255, 0);

// Class and Subclass
TClass<AActor> myActorSpecific
TSubclassOf<AActor> myActorDerived;

// Array of varying subclass objects
TArray<TSubclassOf<AActor>> myListOfActors;

// Struct
struct FMovementAxisDrag
{
	FVector Move = FVector(100.f, 100.f, 100.f);
	FRotator Rotate = FRotator(10.f, 10.f, 10.f);
};