Added a filter option to the prefab randomizer. Changed the default value of the prefab randomizer actor's RandomizeOnBeginPlay to false. Set this to true in the editor if you want them to randomize on begin play

Author: coderespawn

Source/PrefabricatorRuntime/Private/Prefab/Random/PrefabRandomizerActor.cpp

@@ -90,15 +90,23 @@ void APrefabRandomizer::Randomize(int32 InSeed)
 {
 	Random.Initialize(InSeed);
 
-	// Grab all the actors in the level
+	const bool bRandomizeEverythingInLevel = (ActorsToRandomize.Num() == 0); 
+	TArray<APrefabActor*> TargetActors;
 	ULevel* CurrentLevel = GetLevel();
-	TArray<APrefabActor*> AllPrefabsInLevel;
-	GetActorsInLevel(CurrentLevel, AllPrefabsInLevel);
+	if (bRandomizeEverythingInLevel) {
+		// Grab all the actors in the level
+		GetActorsInLevel(CurrentLevel, TargetActors);
+	}
+	else {
+		TargetActors = ActorsToRandomize;
+	}
 
+	if (TargetActors.Num() == 0) return;
+	
 	// Build only the top level prefabs
-	TArray<APrefabActor*> TopLevelPrefabs = AllPrefabsInLevel.FilterByPredicate([](APrefabActor* InPrefab) -> bool {
+	TArray<APrefabActor*> TopLevelPrefabs = TargetActors.FilterByPredicate([](APrefabActor* InPrefab) -> bool {
 		AActor* Parent = InPrefab->GetAttachParentActor();
-		bool bChildOfAnotherPrefab = Parent && Parent->IsA<APrefabActor>();
+		const bool bChildOfAnotherPrefab = Parent && Parent->IsA<APrefabActor>();
 		return !bChildOfAnotherPrefab;
 	});
 
@@ -110,8 +118,25 @@ void APrefabRandomizer::Randomize(int32 InSeed)
 	GetActorsInLevel(CurrentLevel, SeedLinkersInLevel);
 	for (APrefabSeedLinker* SeedLinker : SeedLinkersInLevel) {
 		SanitizeArray(SeedLinker->LinkedActors);
-		if (SeedLinker->LinkedActors.Num() > 1) {
-			int32 LinkedSeeds = SeedLinker->LinkedActors[0]->Seed;
+
+		// If we are randomizing only selected actors, check if the seed linker links to one of them
+		bool bValidSeedLinker;
+		if (!bRandomizeEverythingInLevel) {
+			bValidSeedLinker = false;
+			for (TWeakObjectPtr<APrefabActor> LinkedActor : SeedLinker->LinkedActors) {
+				if (!LinkedActor.IsValid()) continue;
+				if (TargetActors.Contains(LinkedActor)) {
+					bValidSeedLinker = true;
+					break;
+				}
+			}
+		}
+		else {
+			bValidSeedLinker = true;
+		}
+		
+		if (bValidSeedLinker && SeedLinker->LinkedActors.Num() > 1) {
+			const int32 LinkedSeeds = SeedLinker->LinkedActors[0]->Seed;
 			for (int i = 1; i < SeedLinker->LinkedActors.Num(); i++) {
 				SeedLinker->LinkedActors[i]->Seed = LinkedSeeds;
 			}

Source/PrefabricatorRuntime/Private/Utils/PrefabricatorFunctionLibrary.cpp

@@ -43,6 +43,10 @@ void UPrefabricatorBlueprintLibrary::RandomizePrefab(APrefabActor* PrefabActor,
 	FPrefabTools::LoadStateFromPrefabAsset(PrefabActor, LoadSettings);
 }
 
+void UPrefabricatorBlueprintLibrary::UnlinkPrefab(APrefabActor* PrefabActor) {
+	FPrefabTools::UnlinkAndDestroyPrefabActor(PrefabActor);
+}
+
 void UPrefabricatorBlueprintLibrary::GetAllAttachedActors(AActor* Prefab, TArray<AActor*>& AttachedActors)
 {
 	if (!Prefab) return;

Source/PrefabricatorRuntime/Public/Prefab/Random/PrefabRandomizerActor.h

@@ -3,6 +3,8 @@
 #pragma once
 #include "CoreMinimal.h"
 #include "GameFramework/Actor.h"
+#include "Prefab/PrefabActor.h"
+
 #include "PrefabRandomizerActor.generated.h"
 
 DECLARE_DYNAMIC_MULTICAST_DELEGATE(FPrefabRandomizerCompleteBindableEvent);
@@ -26,7 +28,7 @@ class PREFABRICATORRUNTIME_API APrefabRandomizer : public AActor {
 
 public:
 	UPROPERTY(EditAnywhere, Category = "Prefabricator")
-	bool bRandomizeOnBeginPlay = true;
+	bool bRandomizeOnBeginPlay = false;
 
 	UPROPERTY(EditAnywhere, Category = "Prefabricator")
 	int32 SeedOffset = 0;
@@ -40,6 +42,10 @@ class PREFABRICATORRUNTIME_API APrefabRandomizer : public AActor {
 	UPROPERTY(EditAnywhere, Category = "Prefabricator")
 	bool bFastSyncBuild = false;
 
+	/** If left empty, everything in the level will be randomized.  If set, only the actors in the list will be randomized. */
+	UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "Prefabricator")
+	TArray<APrefabActor*> ActorsToRandomize;
+
 private:
 	TSharedPtr<class FPrefabBuildSystem> BuildSystem;
 	FRandomStream Random;

Source/PrefabricatorRuntime/Public/Utils/PrefabricatorFunctionLibrary.h

@@ -20,6 +20,9 @@ class PREFABRICATORRUNTIME_API UPrefabricatorBlueprintLibrary : public UBlueprin
 	UFUNCTION(BlueprintCallable, Category = "Prefabricator")
 	static void RandomizePrefab(APrefabActor* PrefabActor, const FRandomStream& InRandom);
 
+	UFUNCTION(BlueprintCallable, Category = "Prefabricator")
+	static void UnlinkPrefab(APrefabActor* PrefabActor);
+
 	UFUNCTION(BlueprintCallable, Category = "Prefabricator")
 	static void GetAllAttachedActors(AActor* Prefab, TArray<AActor*>& AttachedActors);