4.7 C++ Transition Guide

[Rama]

Dear Community,

Here is a thread where we can all compare our notes as we upgrade projects to 4.7!

Please post the compile errors you encountered and then resolved to help others along!

Also you are welcome to post questions here about compile errors you cant resolve.

Again this is a thread where everyone is welcome to contribute!

~~~

Generated Body

Time to switch over every .h file you have to use GENERATED_BODY !

Also note you will probably want to add public: if you put your BP vars at the top of the class.

Also note you need to include your class constructor now as well.

this

UCLASS()
class AJoyMechPower : public AJoyMechFire
{
    GENERATED_UCLASS_BODY()

becomes this

UCLASS()
class AJoyMechPower : public AJoyMechFire
{
    GENERATED_BODY()
	
public:
    AJoyMechPower(const FObjectInitializer& ObjectInitializer);

~~~

RPCs in 4.7

You will likely encounter errors with your function calls like

UFUNCTION(Server,Reliable,WithValidation)
void YourServerFunc();

UFUNCTION(Client,Reliable,WithValidation)
void YourClientFunc();

Please see this note from Epic Ryan G.

Hey everyone,

Sorry for the confusion about this. The automatic generation of _Implementation and _Validate function declarations has been deprecated in 4.7, and will likely be removed in 4.8, so you should update your RPCs and add these declarations.

Some of you may not be seeing the warning because it will only be emitted if the class containing the RPC function uses the GENERATED_BODY macro, and not if the class uses GENERATED_UCLASS_BODY.

Full details in this thread

~~~

Code Sample

this

UFUNCTION(Reliable,Server,WithValidation)
void SERVER_UpdateArmorMorph(FName Name, float Value);

becomes this

UFUNCTION(Reliable,Server,WithValidation)
void SERVER_UpdateArmorMorph(FName Name, float Value);
bool SERVER_UpdateArmorMorph_Validate(FName Name, float Value);
void SERVER_UpdateArmorMorph_Implementation(FName Name, float Value);

♥

Rama

[TheJamsh]

Nice one Rama

[kylawl]

ACharacter::OnJumped_Implmentation() is not virtual

ACharacter::OnJumped() has been changed to a BlueprintNativeEvent and the new explicitly declared ACharacter::OnJumped_Implmentation() is not marked as virtual.

There was already a bug logged here https://answers.unrealengine.com/que...ual-47-p4.html and the issue has been resolved in github master.

Make OnJumped_Imlementation() in Character.h virtual and you should be sorted.

virtual void OnJumped_Implementation();

[Rama]

Set Sound Class Volume

FAudioDevice::SetClassVolume does not exist


I had to change my Victory BP Library node for Setting the volume of any class from this:

bool UVictoryBPFunctionLibrary::VictorySoundVolumeChange(USoundClass* SoundClassObject, float NewVolume)
 {
	FAudioDevice* Device = GEngine->GetAudioDevice();
	if (!Device || !SoundClassObject)
	{
		return false;
	}
	    
	bool bFound = Device->SoundClasses.Contains(SoundClassObject);
	if(bFound)
	{ 
		Device->SetClassVolume(SoundClassObject, NewVolume);
		return true;
	}
	return false;
 }

to this:

bool UVictoryBPFunctionLibrary::VictorySoundVolumeChange(USoundClass* SoundClassObject, float NewVolume)
 {
       if(!SoundClassObject) 
       {
         return false;
       }

	SoundClassObject->Properties.Volume = NewVolume;

	return true; 
 }

Quite the improvement! Thanks Epic!

~~~

More info

Check out SoundClass.h and in particular:

FSoundClassProperties

Enjoy!

Rama

[Rama]

Controller ID

ULocalPlayer::ControllerID is private now, so this

LP->ControllerId

becomes this

LP->GetControllerId()

Rama

[SaxonRah]

• No special constructors needed! Your class constructors no longer need to take an Object Initializer argument.

Header.h

#pragma once
#include "GameFramework/Actor.h"
#include "Euclib.generated.h"

UCLASS()
class GAMEPROJECT_API AEuclib : public AActor
{
    GENERATED_BODY()
    
public:    
    // Sets default values for this actor's properties
    AEuclib();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

};

Source.cpp

#include "GameProject.h"
#include "Euclib.h"

// Sets default values
AEuclib::AEuclib()
{}

// Called when the game starts or when spawned
void AEuclib::BeginPlay()
{
    Super::BeginPlay();  
}

[TheAgent]

Setting or clearing timers have to be done with TimerHandlers now

FTimerHandle HitHeadFalse;
GetWorldTimerManager().ClearTimer(HitHeadFalse);
GetWorldTimerManager().SetTimer(HitHeadFalse, this, &ABM_EnemyPawn::HitHeadFalse, 0.65f, false,-1.0f);

To play sounds, you have to do it this way now as well

UGameplayStatics::PlaySoundAtLocation(this,HurtSound, this->GetActorLocation(), 1.0, 1.0);

[DamirH]

Not a transition guide on its own, but still related and very important to note (also very awesome):

New: Greatly improved the quality of C++ IDE code completion and error checking with Unreal Engine C++ projects
Xcode and Visual Studio projects will now have more reliable IntelliSense results
We now emit compiler definitions and include paths for editor targets (instead of runtime targets), which are much more inclusive
Fixed project targets "infecting" IntelliSense definitions of other target's project files

[Rama]

FTimerHandle / Timers in 4.7

Setting or clearing timers have to be done with TimerHandlers now

FTimerHandle HitHeadFalse;
GetWorldTimerManager().ClearTimer(HitHeadFalse);
GetWorldTimerManager().SetTimer(HitHeadFalse, this, &ABM_EnemyPawn::HitHeadFalse, 0.65f, false,-1.0f);

Thanks for sharing TheAgent!

To expand on this new use of FTimerHandle, you have to store a var in your .h file in order to clear a timer outside of the scope in which it was declared.

See ShooterGame for example:

ShooterAIController.h

/** Handle for efficient management of Respawn timer */
00064: FTimerHandle TimerHandle_Respawn;

.cpp

void AShooterAIController::BeginInactiveState()
{
	Super::BeginInactiveState();

	AGameState* GameState = GetWorld()->GameState;

	const float MinRespawnDelay = (GameState && GameState->GameModeClass) ? GetDefault<AGameMode>(GameState->GameModeClass)->MinRespawnDelay : 1.0f;

	GetWorldTimerManager().SetTimer(TimerHandle_Respawn, this, &AShooterAIController::Respawn, MinRespawnDelay);
}


//~~~


void AShooterAIController::GameHasEnded(AActor* EndGameFocus, bool bIsWinner)
{
	// Stop the behaviour tree/logic
	BehaviorComp->StopTree();

	// Stop any movement we already have
	StopMovement();

	// Cancel the repsawn timer
	GetWorldTimerManager().ClearTimer(TimerHandle_Respawn);

	// Clear any enemy
	SetEnemy(NULL);

	// Finally stop firing
	AShooterBot* MyBot = Cast<AShooterBot>(GetPawn());
	AShooterWeapon* MyWeapon = MyBot ? MyBot->GetWeapon() : NULL;
	if (MyWeapon == NULL)
	{
		return;
	}
	MyBot->StopWeaponFire();	
}

~~~

Timer Macros For You

I've created (and have been using) four macros you can use if you like!

SETTIMER passes in a dummy TimerHandle, you cannot clear a timer started this way (this is done even in the ue4 code base if you look)

SETTIMERH lets you pass in a FTimerHandle that you can then use with CLEARTIMER

Remember that the FTimerHandle must be declared in your .h if you want to clear the timer in a different function than the one in which it was started.

Enjoy!

#define SETTIMER(param1,param2,param3) FTimerHandle TimerHandle; (GetWorldTimerManager().SetTimer(TimerHandle, this, &param1, param2, param3))


#define SETTIMERH(handle, param1,param2,param3) (GetWorldTimerManager().SetTimer(handle, this, &param1, param2, param3))

#define CLEARTIMER(handle) (GetWorldTimerManager().ClearTimer(handle))

#define ISTIMERACTIVE(handle) (GetWorldTimerManager().IsTimerActive(handle))


_

Example Use:

.h

FTimerHandle TH_CreateApexCreationPieces;

.cpp

void AStructureCreation::CreationProcess_Phase1()
{	
	CreationCount = 0; 
	
	SETTIMERH(TH_CreateApexCreationPieces,AStructureCreation::T_CreateApexCreationPieces,0.23,true);
} 
void AStructureCreation::T_CreateApexCreationPieces()
{
	//how many of the apex rocks are we creating?
	AStructureCreationApex* DefaultObj = StructureCreationApexBP->GetDefaultObject<AStructureCreationApex>(); 
	if(!DefaultObj)
	{
		UE_LOG(Joy,Error,TEXT("AStructureCreation::CreationProcess_Phase1()>> NO DEFAULT OBJ!!!!!!"));
		CLEARTIMER(TH_CreateApexCreationPieces);
		return;
	} 
///....
}

[ngrts]

Don't forget, the official release notes (not the forum announcement) spell out a lot of the breaking changes affecting C++ code.

[DamirH]

Header.h

#pragma once
#include "GameFramework/Actor.h"
#include "Euclib.generated.h"

UCLASS()
class GAMEPROJECT_API AEuclib : public AActor
{
    GENERATED_BODY()
    
public:    
    // Sets default values for this actor's properties
    AEuclib();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

};

Source.cpp

#include "GameProject.h"
#include "Euclib.h"

// Sets default values
AEuclib::AEuclib()
{}

// Called when the game starts or when spawned
void AEuclib::BeginPlay()
{
    Super::BeginPlay();  
}

As I learned the hard way, not only are you not required to add a call to Super() in the constructor, but if you do, your editor will crash on startup.

[Brainshack]

Header.h

#pragma once
#include "GameFramework/Actor.h"
#include "Euclib.generated.h"

UCLASS()
class GAMEPROJECT_API AEuclib : public AActor
{
    GENERATED_BODY()
    
public:    
    // Sets default values for this actor's properties
    AEuclib();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

};

Source.cpp

#include "GameProject.h"
#include "Euclib.h"

// Sets default values
AEuclib::AEuclib()
{}

// Called when the game starts or when spawned
void AEuclib::BeginPlay()
{
    Super::BeginPlay();  
}

With PCIP gone, how do I now create components?

[DamirH]

Just remove the OI. (or PCIP.) from your code.

[_neo_]

In AiController the GetFocalPoint is not virtual anymore.

FVector GetFocalPoint() const; 

Instead, you can now inherit from:

virtual FVector GetFocalPointOnActor(const AActor *Actor) const; 

Edit: Also, after upgrading to 4.7 I had to re-tick the Environment Query System in the Editor Preferences/Experimental.

[Brainshack]

So, I tried to convert my project to 4.7. I have cleaned up the constructor of my player controller, and get the following error:

Error	7	error C2512: 'APlayerController' : no appropriate default constructor available	C:\Users\Christian\Documents\Unreal Projects\SurvivalSim\Source\SurvivalSim\SurvivalPlayerController.cpp	8	1	SurvivalSim

ASurvivalPlayerController::ASurvivalPlayerController()
{
	
	PrimaryActorTick.bCanEverTick = true;
	bShowMouseCursor = true;

}

Im not sure, if I am even on 4.7 yet, since I cannot convert it without buidling. When I right click on my projectfile and try to switch versions, I only get the message "Failed to generate Project files". When I try to open my project from the 4.7 editor, it wants to rebuild the project, but then failes. When I now go to VS, I get the above error during compile.