Unreal Engine

Currently using UE4 (4.10.4)

Links

UE4

• Iterate actor/object/class

Blender

• Blender 3D Design Course

• Export Options (so that the object is not lying on the side after Export/Import):
  • Forward: Y Forward
  • Up: Z up

• Changing the object's origin to its bottom:
  • Switch to Edit Mode if needed (Tab). With vertex selection on, choose the center vertex in the bottom. Press Shift+S and choose Cursor to Selected. The 3D cursor will move to the selected vertex. Deselect all and switch to Object Mode (Tab).
  • In Tools choose Set Origin and then Origin to 3D Cursor.
  • Make sure the object's coordinates are set to 0,0,0. Now the object should be placed properly on the XY plane.

C++

Variable names

If you want to use real variable names but have nice names in the UE editor too, then use meta/DisplayName

UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Camera, Meta = (DisplayName = "First Person Camera Component") )
    UCameraComponent* m_pFirstPersonCameraComponent;

owner / client /server

The instance that spawned the class is always ROLE_Authority. If an Actor is spawned on the client, the client is the authority. 
-- OmaManfred

OmaManfred::

 
And concerning the owner stuff:


When you spawn an instance of a class on the server FOR Client A, you have to set him as the owner.

FActorSpawnParameters params;
params.Owner = PlayerAPlayerController;

SpawnActor<Class>(Class:StaticClass(),params);

Then on Client B you can say IsOwner(PlayerBPlayerController), which should return false. 

Logging

The following is just a copy/paste/change from the UE4 wiki and was really done from different persons, I am just using the work of different people here. Put it in a Log.h and include it into your <your_project>.h file after the #include "Engine.h". Because <your_project>.h is in every of your files, you will now be able to use these macros in every .cpp file.

#pragma once

#include "Log.h"
#include "Engine.h"

// macros
// - LOG_LINE
// - LOG -> output log
// -- LOG("text");
// -- LOG("text %s %f %d", "text", 1.2, 5);
// - PRINT -> screen
// -- PRINT("text");
// -- PRINT("text %s %f %d", "text", 1.2, 5);

#if _MSC_VER
#define FUNC_NAME    TEXT(__FUNCTION__)
#else // FIXME - GCC?
#define FUNC_NAME    TEXT(__func__)
#endif

#define LOG_LINE UE_LOG(LogTemp, Warning, TEXT("%s, file: %s, line %d"), FUNC_NAME, *FString(__FILE__), __LINE__);
//#define LOG_NULL(s, p) UE_LOG(LogTemp, Warning, TEXT("pointer %s %s"),s, (p?TEXT("ok"):TEXT("null") ) );

#define PRINT(format, ...) \
{ \
	const FString sFunc = FString::Printf(TEXT("%s"), FUNC_NAME); \
	const FString sText = FString::Printf(TEXT(format), ##__VA_ARGS__); \
	const FString sMsg = FString::Printf(TEXT("%s() : %s"), *sFunc, *sText); \
	if (GEngine) GEngine->AddOnScreenDebugMessage(-1, 5, FColor::White, sMsg); \
}

#define LOG(format, ...) \
{ \
    const FString sMsg = FString::Printf(TEXT(format), ##__VA_ARGS__); \
    UE_LOG(LogTemp, Warning, TEXT("%s() : %s"), FUNC_NAME, *sMsg);\
}

Am I client or server ?

https://answers.unrealengine.com/questions/416305/how-to-know-if-listenserverclient-owner-for-rpc.html

To answer questions 1 and 2: you can use AActor::GetNetMode() 
which returns whether you are a listen server, dedicated server or network client.

         if (GetNetMode() == ENetMode::NM_ListenServer)
         {
         }
         

The ENetMode values are:

    NM_Standalone = 0

    NM_DedicatedServer = 1

    NM_ListenServer = 2

    NM_Client = 3 // is only when you are actually connected to a server

The ordering of the ENetMode values allows you to check multiple things at once: 
GetNetMode() <= 2 means you are the server or standalone, so you have 'global authority'.

UMG with C++ base class

• create a normal UMG widget
• create a C++ class with base class UserWidget (UUserWidget)
• build the project
• set the parent class of the UMG widget to your C++ class
• in <Project>.Build.cs add "UMG", "SLATE", "SLATECORE":

PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "UMG" });

		PrivateDependencyModuleNames.AddRange(new string[] {  });

		// Uncomment if you are using Slate UI
		 PrivateDependencyModuleNames.AddRange(new string[] { "Slate", "SlateCore" });

• put into <Project>.h

#include "Runtime/UMG/Public/UMG.h"
#include "Runtime/UMG/Public/UMGStyle.h"
#include "Runtime/UMG/Public/Slate/SObjectWidget.h"
#include "Runtime/UMG/Public/IUMGModule.h"
#include "Runtime/UMG/Public/Blueprint/UserWidget.h"

SLATE

https://wiki.unrealengine.com/Slate_Introduction_%E2%80%92_Basic_Menu_Part_1

The "canvas" in UMG is "SConstraintCanvas" in Slate.

Multiplayer / Sessions

Do not search for "multiplayer", search for "sessions". Good tutorial: https://wiki.unrealengine.com/How_To_Use_Sessions_In_C%2B%2B

String conversions

from: https://docs.unrealengine.com/en-us/Programming/UnrealArchitecture/StringHandling/FString

FString TestHUDString = FString(TEXT("This is my test FString."));
FName TestHUDName = FName(*TestHUDString);
FText TestHUDText = FText::FromString(TestHUDString);

Misc

Source control

The minimum you have to put under source control:

/Config
/Content
/Source
Project.uproject

Other Licenses (examples)

not allowed

• GNU General Public License (GPL),
• Lesser GPL (LGPL) (unless you are merely dynamically linking a shared library), or
• Creative Commons Attribution-ShareAlike License.

Code or content under the following licenses, for example, are allowed

• BSD License,
• MIT License,
• Microsoft Public License, or
• Apache License.

Other

Escape key stops simulation in editor

If you want to change this behavior, open "Edit/Editor Preferences" and search for "stop". Then change under "Play World/Stop" the shortcut "Escape" to whatever you want, for example shift-Escape.

Black Screens or flickering/invisible new action popup

Disable multiplane overlay