DefineXPropertyDefaultValue (Unreal Engine)

- Declaration

static void DefineColorPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, FLinearColor PropertyValue);

static void DefineBoolPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, bool PropertyValue);

static void DefineFloatPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, float PropertyValue);

static void DefineStringPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, FString PropertyValue);

static void DefineVectorPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, FVector4 PropertyValue);

static void DefineTransformPropertyDefaultValue(FCavrnusSpaceConnection SpaceConnection, const FString& ContainerName, const FString& PropertyName, FTransform PropertyValue);

- Description

Defines what the application will show if a new prop value has not been assigned.

This default is useful for when you call Bind for objects that already have an existing “state” built into your application. Binding to a property with no defined Default and no property assignments yet value will give you blank data (Color[0,0,0,0], etc) as its initial state. This would result in things like the transforms of built-in objects jumping to the scene origin as soon as they Bind their transform property. DefineXPropertyDefaultValue prevents this.

Once an update has been posted to the journal for this property value the default becomes irrelevant.

- Blueprint Sample

Define Transform Property Default

- Code Sample

Example case - color and height of a flag.

FlagActor.h

#include "GameFramework/Actor.h"
#include "Types/CavrnusSpaceConnection.h"
#include "FlagActor.generated.h"

UCLASS()
class MODULE_API AFlagActor : public AActor
{
  GENERATED_BODY()
  
public:
  void InitializeProperties(FString& InContainerName, FCavrnusSpaceConnection& InSpaceConnection);
  
private:
  UPROPERTY()
  LinearColor FlagColor;
  
  UPROPERTY()
  float FlagHeight;
  
  // Objects that synchronize properties should be created using UCavrnusFunctionLibrary::SpawnObject. This gives the spawner back the properties container name that this object will use in the journal.
  FString ContainerName;
  
  FCavrnusSpaceConnection SpaceConnection;
};

FlagActor.cpp

#include "FlagActor.h"
#include "CavrnusFunctionLibrary.h"

void AFlagActor::InitializeProperties(FString& InContainerName, FCavrnusSpaceConnection& InSpaceConnection)
{
  ContainerName = InContainerName;
  SpaceConnection = InSpaceConnection;
  
  UCavrnusFunctionLibrary::DefineColorPropertyDefaultValue(InSpaceConnection, InContainerName, "FlagColor", FlagColor);
  UCavrnusFunctionLibrary::DefineFloatPropertyDefaultValue(InSpaceConnection, InContainerName, "FlagHeight", FlagHeight);
}