2. Unreal Engine and C++
We’re finally at a point where we can start working in C++ with Unreal Engine
To get everything set up for this properly, we’re going to need an IDE to create C++ files in
Which Unreal Engine can link to

3. Unreal Engine and C++
As of Unreal Engine 4.18, we can use Visual Studio Code as a C++ IDE
And Unreal Engine will act as the compiler
This is a lightweight application that acts as a text editor
Though has many extensions for supporting syntax highlighting, code completion, and debugging
For lots of different languages
Make sure these are definitely installed before moving on
Windows: Latest Visual Studio Community Edition 2015/2017
Mac: Latest XCode

4. When making a new project, we see two tabs at the top
Making a C++ Project
To use C++ in an Unreal Engine project, we actually need to use a different project type
When making a new project, we see two tabs at the top
Blueprints
C++

5. Feel free to keep the starter content
Making a C++ Project
Make sure that C++ is selected
Then select Basic Code
Give it a location/name
Then click on Create Project
Feel free to keep the starter content

6. Making a C++ Project Two things will happen here
Unreal Engine will open as normal (like it does whenever we make a project)
The default C++ IDE will open as well
Windows: Visual Studio 2015/2017
Mac: Xcode
If the program crashes, it’s most likely due to 4.18 requiring the latest updates for Visual Studio/Xcode
If an earlier Unreal Engine is installed (like 4.16), feel free to use that for now
And repeat the earlier steps to make the C++ project

7. The IDE will take quite a while to get set up
Making a C++ Project
The IDE will take quite a while to get set up
This is because it has to look through all the C++ files in the project
Including all the C++ files in Unreal Engine as a whole

8. Making a C++ Project Ex
First, make sure the latest version of Visual Studio 2015/2017 or XCode is installed
Then run Unreal Engine
Create a new C++ project
Choose the Basic Code template
Choose its name and location
Click on Create Project

9. Opening a C++ File
In Unreal Engine, most C++ files act as templates to be used
Like parent classes
Once a C++ file has been made, we decide how it works
Afterwards we make an item in Unreal Engine and make it extend the C++ functionality

10. Opening a C++ File
We can see all the C++ files the project uses from the Content Browser
Click on the Folder icon near the top
Choose C++ Classes
Here we’ll see everything it contains so far

11. Opening a C++ File
All C++ Basic Code projects start with a single C++ file
The Game Mode of the current level
Let’s look at this file in our C++ IDE

12. Opening a C++ File The IDE project actually contains two key areas
The source code of the engine itself
The source code of the project
This is separated into two folders: Engine and Games
Expand the Games folder
Expand the Project folder
Expand the Source folder
Expand the Project folder inside
This is where all the C++ files will go

13. Opening a C++ File
The C++ source (.cpp) and header (.h) files for the project itself are here
Leave them alone, as they attach any C++ code to the project
There’s also the GameModeBase files
Let’s open both the header and source files

14. Opening a C++ File
The source file is empty (we’ll ignore it for now) The header file has some interesting code here

15. Opening a C++ File Every header file has
The namespace (the project’s name)
The class name (prefixed with a letter)
A class to extend

16. Opening a C++ File
The GENERATED_BODY() function is required It lets Unreal Engine make all the necessary files for this class It has to be the first line inside the class So don’t move it

17. Opening a C++ File Let’s tweak this file slightly
We’ll add a constructor to the header file
Note that we need to use the same name as the class
And we need to put it in the public section

18. Opening a C++ File
We’ll then implement this constructor in the source file
We’re going to make it output “Hello World” to the console
But how can we do that?

19. Opening a C++ File Unreal Engine has a UE_LOG function
Lets us output text to a log
Need to specify
Which log to use
The type of log it is
The text to output

20. Opening a C++ File There are a few types of log
Fatal: prints to log and file, and crashes the game
Error: prints to log and file (appears red)
Warning: prints to log and file (appears yellow)
Display: prints to log and file (appears default colour)
Verbose: prints to file only

21. Opening a C++ File
Any time we make a change to a C++ file, we need to tell Unreal Engine to compile those files
We do not compile from the IDE
We can do that by clicking on the Compile button near the top of the editor

22. Opening a C++ File
After some compilation, it’ll say Compile Complete near the bottom of the screen
Now lets change the GameMode of this level to this class
Done in the Blueprints menu
In GameMode
Here we select the C++ file

23. Opening a C++ File With that selected, we’re nearly ready to test this
First we need to show the log in the editor
So we can see our output
This is done from the Window menu
Developer Tools  Output Log

24. Opening a C++ File
Let’s run the game and see if we can spot the output
It can be hard to spot, but it’s there!

25. Opening a C++ File Ex
In your IDE, go to the [ProjectName]GameModeBase files
Games  [ProjectName]  Source  [ProjectName]
Open both the header and source files
Make a public constructor in the header file, and implement it in the source file
Make it output some text to the log
Using UE_LOG
Save the file, and compile it from the Unreal Engine editor
While it’s compiling, open the Output Log window
Once compiled, run your game and look for your output in the log

26. Creating an Actor (1) Just editing this GameMode would by pretty dry
Let’s try creating our own Actor class
At any point in the Content Browser, we can right-click to add a file
At the very top, we’ll see New C++ Class

27. Creating an Actor (1) Clicking on this option opens a familiar window
Looks like the New Blueprint window
That’s because we can make a lot of the same files here
We’ll click on Actor, and then Next

28. Creating an Actor (1) We then need to decide on
It’s name: this is what we’d refer to it as in Unreal Engine
It’s location: which we always leave alone
If it’s public or private
Public classes can be used in other projects
Private classes cannot
We’ll choose public for this one, and we’ll call it RotatingCube
Can finish by clicking on Create Class

29. This adds two files in a Public and Private folder
Creating an Actor (1)
This adds two files in a Public and Private folder
The header and source files

30. Creating an Actor (1) We have the class name Also has GENERATED_BODY()
Prefixed with A like before
Also has GENERATED_BODY()
But it has some more functions this time
A constructor
The BeginPlay function
The Tick function

31. Creating an Actor (1)
The BeginPlay and Tick functions work like the events do in a Blueprint
Whenever these events are triggered, these functions are called first
Then the Blueprint logic

32. Creating an Actor (1)
Let’s go to the source file and see these functions
They are all here, and ready to go

33. Creating an Actor (1) The constructor sets a Boolean flag to true
This lets the actor tick
Meaning we can run some logic every update
The BeginPlay and Tick functions simply run their parent’s version
We need to keep these here
As they help Unreal Engine position and render the actor

34. Creating an Actor (1)
Let’s output something to the log when this actor appears in the level
Via BeginPlay
We’ll then compile our code

35. Creating an Actor (1) Ex Right-click anywhere in your Content Browser
And select New C++ Class
Select Actor as the parent class
Call it RotatingCube
Make the class Public
In your IDE, open the source file of this class
Add a log message to the BeginPlay function
Compile your C++ code in the Unreal Engine editor

36. Creating an Actor (2)
Whenever we make a C++ class like this, we need to make a Blueprint for it
Otherwise we can’t use it in the game
As such, C++ class act as abstract parents
We can’t use them directly
But we can make children that use them
We’re going to make a folder in the Content Browser for any actors we make

37. Creating an Actor (2) Inside here, we’ll make the Blueprint
By right-clicking
And choose New Blueprint Class
Here, we usually select one of the main options
This time we’re going to go into More Classes at the bottom

38. Creating an Actor (2) Here we can search for the class we made
RotatingCube
It appears as an option
We’ll select that one and click on Select

39. Creating an Actor (2) We’ll call this Blueprint RotatingCube_B
There’s nothing wrong with using the same name
But if we’re making a C++ class that acts as an object, it’s best to give the Blueprint class a different name
To show that it is the Blueprint version

40. Creating an Actor (2)
With it made we can open it in the Blueprint editor
Let’s give it a StaticMesh
So it’s visible in the scene

41. Creating an Actor (2)
With the Blueprint set up, let’s add one of these to the scene
Once done, we can play the game

42. Creating an Actor (2)
When we play, we can see the output in the log!
We’re now ready to add some more complex logic to this Actor!

43. Creating an Actor (2) Ex
Make a folder in the Content Browser for your “Actors”
Create a Blueprint in this folder
Using the C++ class you made as its parent
Call it RotatingCube_B
Open it in the Blueprint Editor, and give it a StaticMesh
To make it visible in the scene
Add one of these to the scene, and play the game
Make sure you see the output for the Actor in the output log

44. Transforming Actors in C++
If we want to make this cube rotate, we would have added a AddRotation node to the Tick event in the Blueprint
However, this C++ class is made for this rotating-ness
So we can ‘hard-code’ it into the Tick event in C++

45. Transforming Actors in C++
To do this, we’re going to add three instance variables to the header file
The rotation speeds in the X, Y, and Z axes
These are going to be floats
As Unreal Engine uses floats to store accurate decimal values
We’ll make them in a private section
Remember that classes are private by default!

46. Transforming Actors in C++
We’ll then give these values in the constructor
We’ll set the X to 180
And Y and Z to 0
These are going to be degrees per second

47. Transforming Actors in C++
If we want to rotate the Actor, we can use the AddActorWorldRotation function
The same as the Blueprint node!
For this though, we need a Rotator object

48. Transforming Actors in C++
We create a Rotate using the FRotator data-type
It is a struct that contains variables for
The pitch (Y rotation)
The yaw (Z rotation)
The roll (X rotation)

49. Transforming Actors in C++
As this is a value (not a reference), this Rotator will not exist outside this function
So no memory management to worry about

50. Transforming Actors in C++
However, just this isn’t good enough
As we’re going to add 180 degrees every tick
We want it to be every second
So we have to multiply each value by DeltaTime
DeltaTime is the amount of time elapsed since the previous tick
It keeps games running frame independently

51. Transforming Actors in C++
We can then pass this Rotator into the AddActorWorldRotation function!

52. Transforming Actors in C++
If we compile our C++ code and run the game, we’ll see the cube now rotates!

53. Transforming Actors in C++ Ex
Make three private instance variables in the Actor’s C++ class
For the rotation speed in each axis
Give them any values you want in the constructor
In the Tick function, make a FRotator object
By passing in these three variables
Multiplied by the DeltaTime
Run the AddActorWorldRotation function, passing in the FRotator
Compile your C++ code, and run your game
Make sure the cube rotates!

54. Random Rotation Ex
Use FMath::RandRange(min, max) to get a random number 𝑀𝐼𝑁≤𝑥≤𝑀𝐴𝑋
Use this to assign random rotation speeds in the BeginPlay function
Compile your code, and run your game a few times
Make sure the rotation is randomised each time!

55. END OF UNIT!