C++ 4.19 Transition Guide

Development Programming & Scripting C++
21

@muchcharles, I looked into this recently and found out there’s a separate setting for toolchain selection. Without it, it chooses in a really convoluted way based on what it can find installed, preferring 2015 toolchain even if the project files were generated for 2017. At least, that was the behaviour until recently.

You can add the following inside the <Configuration> section of BuildConfiguration.xml to force it:


<WindowsPlatform>
    <Compiler>VisualStudio2017</Compiler>
</WindowsPlatform>
22

I posted a question about this, but does anyone know off the bat why player input (keyboard, mouse, xbox controller, etc.) doesn’t work in 4.19 for me until I SHIFT + F1 to get the mouse cursor, then click back in the game? In 4.18 it works just fine.

23

Anyone?
The impact is quite strong, my application is running at 120FPS in UE4.18 but only at 50FPS in UE4.19.

24

Have you submitted a bug using the bug submission form?

26

I am having some mac-only issues compiling third party plugin on 4.19:

error CS0103: The name ‘PublicDefinitions’ does not exist in the current context

from 4.19 release notes : New: The Module Rules “Definitions” property has been renamed to “Public Definitions”, to make its semantics clearer. A complementary “Private Definitions” property has also been added.

Are there issues using PublicDefintions on mac?

(Same code compiles on windows)

[UPDATE]
[DOH]
Self-inflicted. Forgot to resolve .uproject. Works on mac. Please disregard
[/DOH]
[/UPDATE]

27

actually, I’d like someone to verify that, maybe it’s related to my machine or something…?

28

According to the official documentation at http://api.unrealengine.com/INT/API/Runtime/Engine/Engine/UEngine/AddOnScreenDebugMessage/ the signature for AddOnScreenDebugMessage is as follows:



AddOnScreenDebugMessage
(
    uint64 Key,
    float TimeToDisplay,
    FColor DisplayColor,
    const FString & DebugMessage,
    bool bNewerOnTop,
    const FVector2D & TextScale
)

AddOnScreenDebugMessage
(
    int32 Key,
    float TimeToDisplay,
    FColor DisplayColor,
    const FString & DebugMessage,
    bool bNewerOnTop,
    const FVector2D & TextScale
)

The signature did not changed from 4.18 but the behavior did. Now it won’t work for us with key set to anything other than -1 (INDEX_NONE). Any FString passed with key other than INDEX_NONE won’t apper on the screen. Unfortunately, tt breaks our logging system and I cannot figure out why.

29

If anyone else is getting the following errors

during compilation of Shader Files inheriting from FGlobalShader after transitioning to 4.19, here’s the two fixes you need:

  1. Change the arguments of ModifyCompilationEnvironment from EShaderPlatform to const FGlobalShaderPermutationParameters&:
    example:
    from

void FMyShaderDeclaration::ModifyCompilationEnvironment(EShaderPlatform Platform, FShaderCompilerEnvironment& OutEnvironment)
	{
	    FGlobalShader::ModifyCompilationEnvironment(Platform, OutEnvironment);
	    OutEnvironment.CompilerFlags.Add(CFLAG_StandardOptimization);
	}


to


void FMyShaderDeclaration::ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& PermutationParams, FShaderCompilerEnvironment& OutEnvironment)
	{
	    FGlobalShader::ModifyCompilationEnvironment(PermutationParams, OutEnvironment);
	    OutEnvironment.CompilerFlags.Add(CFLAG_StandardOptimization);
	}
  1. Add the ShouldCompilePermutation method for each shader:
    example:

static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& PermutationParams)
	{
	    // Useful when adding a permutation of a particular shader
	    return true;
	}


It works, but there's probably a more reasonable approach than simply returning true here. I'd be grateful if someone could provide some info about that.

All of this only applies to your project when you’re using global shaders (necessary for compute shaders), especially when using the popular UE4ShaderPluginDemo or one of its forks. For more information about how to set up Global Shaders see this blogpost: Yet another blog...: Adding Global shaders to UE4 v2.0

Adding this so others don’t have to search the web as long as I had to:
Unreal Engine Global Compute Pixel Shader FGlobalShader Compile Error Permutation Transition Uprade 4.19 ModifyCompilationEnvironment Modify Compilation Environment ShouldCompilePermutation Should Compile Permutation EShaderPlatform FGlobalShaderPermutationParameters InPermutationId PermutationId IMPLEMENT_SHADER_TYPE3 IMPLEMENT_SHADER_TYPE implement shader type

30

For anyone coming across this: it’s definitely a bug and now there is a pull request for it at https://github.com/EpicGames/UnrealEngine/pull/4675.

31

I have the same problem

32

Hi, I’m trying to update from 4.17 to 4.19.

Unfortunately, Unreal crashes when starting or during shader compiling

I get this error message:

Has someone a Idea how to fix this?
I’m a little lost right now :smiley:

33

In case anyone else has isssues with GPU stats not working any more after transitioning from 4.18 to 4.19, here’s a fix.

I got the following compiler errors after upgrading to 4.19:

I fixed this by changing my stat declaration macros from


DECLARE_FLOAT_COUNTER_STAT(TEXT("MyFunctionToProfile"), Stat_GPU_MyFunctionToProfile, STATGROUP_GPU);

to


DECLARE_FLOAT_COUNTER_STAT(Stat_GPU_MyFunctionToProfile, TEXT("MyFunctionToProfile"));

Best regards!

GPU, stat gpu, profiling, DECLARE_FLOAT_COUNTER_STAT, DECLARE_FLOAT_COUNTER_STAT, SCOPED_GPU_STAT, GPU visualizer, stat startfile, stat stopfile, session frontend

34

I’m still getting crashes on map load with Nav Mesh running vs 2017 15.7.6

35

have you found the solution?
at 4.21 I have the same error.

36

can I learn more? I also got this error and don’t know how to fix it