Linker errors when using UStreamingLevelKismet::LoadLevelInstance

Development World Creation
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1

Hi,

LoadLevelInstance declaration is missing ENGINE_API. To make it work you will need to add it in LevelStreaming.h.
Like this

ENGINE_API static ULevelStreamingKismet* LoadLevelInstance(

We will add this change in next engine release version (4.18). Or you can use this function from blueprints, this way you will not need to change engine files.

2

Edit, it should be

static ENGINE_API ULevelStreamingKismet* LoadLevelInstance(
3

Hey everyone,

I’m trying to implement some basic procedural dungeon generation. I have created a couple of rooms for the dungeon and saved them as UMaps. I want to load instances of these levels into a persistent dungeon level. I am trying to use UStreamingLevelKismet::LoadLevelInstance to load in these levels but I keep getting linker errors when trying to do this in c++.

void ADungeonGenerator::PlaceRoom()
{
	// Determine room size

	int RoomIndex = FMath::RandRange(0, FilteredRooms.Num() - 1);

	FRoomTypeStruct RoomTypeToPlace = FilteredRooms[RoomIndex];

	int RoomNumberToPlace = FMath::RandRange(0, RoomTypeToPlace.NumberOfRooms - 1);

	FString Tileset;
	if (CurrentTileset.GetValue() == ETileset::EDefault)
	{
		Tileset = "Default/";
	}
	FString MapPath;
	FString LevelName = MapsDirectoryRoot + Tileset + "Rooms/" + FString::FromInt(RoomTypeToPlace.TilesX) + "x" + FString::FromInt(RoomTypeToPlace.TilesY) + "/Room" + FString::FromInt(RoomNumberToPlace);
	
	UE_LOG(LogTemp, Log, TEXT("Loading %s"), *LevelName);

	bool IsRoomLoaded;

	ULevelStreamingKismet* StreamedRoom = ULevelStreamingKismet::LoadLevelInstance(this, LevelName, FVector(0, 0, 0), FRotator(0, 0, 0), IsRoomLoaded);
}

I have the header file included at the top

#include "Runtime/Engine/Classes/Engine/LevelStreamingKismet.h"

Yet I keep getting this error when trying to compile:

error LNK2019: unresolved external symbol “public: static class ULevelStreamingKismet * __cdecl ULevelStreamingKismet::LoadLevelInstance(class UObject *,class FString const &,struct FVector const &,struct FRotator const &,bool &)” (?LoadLevelInstance@ULevelStreamingKismet@@SAPEAV1@PEAVUObject@@AEBVFString@@AEBUFVector@@AEBUFRotator@@AEA_N@Z) referenced in function “protected: void __cdecl ADungeonGenerator::PlaceRoom(void)” (?PlaceRoom@ADungeonGenerator@@IEAAXXZ)

Does anyone have any idea what I am doing wrong here? I haven’t been able to find many detailed examples online of doing this in c++ so any help would be appreciated. Thank you!

4

Got it, I’ll just call the blueprint function for now, thanks for the quick reply!