I got this to working! I’m using the Launcher version, no need to access any source code to modify any engine files.
So, in the editor, make a C++ class child of GameInstance.
The Header file should look like this:
#pragma once
#include "CoreMinimal.h"
#include "Engine/GameInstance.h"
#include "MyGameInstance.generated.h"
UCLASS()
class MYLOCALGAME_API UMyGameInstance : public UGameInstance
{
GENERATED_BODY()
public:
UFUNCTION(BlueprintCallable)
ULocalPlayer * RequestLocalPlayer(int32 ControllerId, FString & OutError, bool bSpawnActor);
};
While the cpp file should look like this:
#include "MyGameInstance.h"
#include "Engine/Engine.h"
#include "Engine/World.h"
#include "Engine/LocalPlayer.h"
ULocalPlayer* UMyGameInstance::RequestLocalPlayer(int32 ControllerId, FString& OutError, bool bSpawnActor)
{
check(GetEngine()->LocalPlayerClass != NULL);
ULocalPlayer* NewPlayer = NULL;
int32 InsertIndex = INDEX_NONE;
const int32 MaxSplitscreenPlayers = 5; // This is what does the trick!
if (FindLocalPlayerFromControllerId(ControllerId) != NULL)
{
OutError = FString::Printf(TEXT("A local player already exists for controller ID %d,"), ControllerId);
}
else if (LocalPlayers.Num() < MaxSplitscreenPlayers)
{
// If the controller ID is not specified then find the first available
if (ControllerId < 0)
{
for (ControllerId = 0; ControllerId < MaxSplitscreenPlayers; ++ControllerId)
{
if (FindLocalPlayerFromControllerId(ControllerId) == NULL)
{
break;
}
}
check(ControllerId < MaxSplitscreenPlayers);
}
else if (ControllerId >= MaxSplitscreenPlayers)
{
UE_LOG(LogPlayerManagement, Warning, TEXT("Controller ID (%d) is unlikely to map to any physical device, so this player will not receive input"), ControllerId);
}
NewPlayer = NewObject<ULocalPlayer>(GetEngine(), GetEngine()->LocalPlayerClass);
InsertIndex = AddLocalPlayer(NewPlayer, ControllerId);
if (bSpawnActor && InsertIndex != INDEX_NONE && () != NULL)
{
if (()->GetNetMode() != NM_Client)
{
// server; spawn a new PlayerController immediately
if (!NewPlayer->SpawnPlayActor("", OutError, ()))
{
RemoveLocalPlayer(NewPlayer);
NewPlayer = NULL;
}
}
else
{
// client; ask the server to let the new player join
NewPlayer->SendSplitJoin();
}
}
}
else
{
OutError = FString::Printf(TEXT("Maximum number of players (%d) already created. Unable to create more."), MaxSplitscreenPlayers);
}
if (OutError != TEXT(""))
{
UE_LOG(LogPlayerManagement, Log, TEXT("UPlayer* creation failed with error: %s"), *OutError);
}
return NewPlayer;
}
What I did was I made a copy of the function that creates a player. the Engine one checks for UGameViewport’s MaxSplitscreenPlayers, which is hard coded to 4.
So instead of go look for the value elswhere, my copy of the function is just set to 5.
The function is Callable from Blueprints, so then you just do this, probably from a GameMode on your 1st map.
Keep in mind you need to set MyGameInstance c++ class as your default game instance in order for it to exist in the game.