Object Handling with FArticyRef

In this section, we'll show how you can use ArticyRef in Unreal to reference Articy objects dynamically, allowing for flexible and reusable code both in C++ and Blueprints.

Getting Started with ArticyRef

Instead of hardcoding the technical name of Articy objects in your code, you can use FArticyRef to manage object references dynamically. This keeps your code generic and more modular.

In Unreal, FArticyRef is a structure used to store references to Articy objects. You can define an ArticyRef in your C++ class and expose it to the editor for easy configuration.

Example: Setting up an ArticyRef in C++

#pragma once
 
#include "CoreMinimal.h"
#include "ArticyRef.h"
#include "MyArticyActor.generated.h"
 
UCLASS()
class MYPROJECT_API AMyArticyActor : public AActor
{
    GENERATED_BODY()
 
public:
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Articy")
    FArticyRef MyRef;
};

After defining MyRef as a public field, you can configure it directly in the Unreal Editor. You can use the Articy Asset Picker to select objects from the Articy database and set them as the reference.

Accessing ArticyRef in Code

Once you’ve set a reference to an object in the editor, you can access and use that reference in your C++ code.

Example: Accessing an ArticyRef

if (MyRef.GetId().IsNull())
{
    UArticyObject* ArticyObject = MyRef.GetObject(GetWorld());
    if (ArticyObject)
    {
        UE_LOG(LogTemp, Warning, TEXT("Object Technical Name: %s"), *ArticyObject->GetTechnicalName().ToString());
    }
}

Here, we use GetId().IsValid() to ensure the reference has been set. The GetObject() method retrieves the Articy object. The returned object is of type UArticyObject, which can then be cast to a more specific type.

Example: Casting to a specific type

if (MyRef.GetId().IsNull())
{
    UManiacManfredCharacter* Manfred = MyRef.GetObject<UManiacManfredCharacter>(GetWorld());
    if (Manfred)
    {
        UE_LOG(LogTemp, Warning, TEXT("Manfred's Display Name: %s"), *Manfred->GetDisplayName().ToString());
    }
}

By specifying the desired type, such as UManiacManfredCharacter, when calling GetObject(), you can directly cast the object and access its properties.

Type Constraints for ArticyRef

To avoid runtime errors caused by assigning an incorrect object type, you can set type constraints for an ArticyRef. This limits the objects that can be assigned to the reference.

Example: Limiting to a specific type

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Articy", meta = (ArticyClassRestriction = "UManiacManfredCharacter"))
FArticyRef PlayerCharacter;

This restricts the objects shown in the Articy Asset Picker to those of type UManiacManfredCharacter, helping to ensure that only valid objects are selected.

Lists and Arrays of ArticyRefs

You can also use lists or arrays of ArticyRef to manage multiple references.

Example: List of ArticyRefs

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Articy")
TArray<FArticyRef> SelectableCharacters;

This allows you to reference multiple Articy objects, providing flexibility for complex setups.

Custom Filters for ArticyRef

In addition to type constraints, you can implement custom filters for ArticyRef in Unreal. While this is an advanced feature, it provides even more control over which objects can be selected.