Get started with Creator Kit: Beginner Code

Get started with code in Unity

Introduction to variables

Write your own instruction

Introduction to functions

Write your own spawn function 

Introduction to classes

 Write your own spawner class

Introduction to the public keyword and inheritance

Customize the health potions

Customize your game

Homework Submissions

WebGL Submissions - Create your first Action-RPG with C#

Live Session - Create your first Action-RPG Game with C#

Creator Kit: Beginner Code

In this activity, students customize their own 3D role-play video games using Unity technology and C# computer coding. All activity assets and step-by-step tutorials are included, helping learners to get started quickly. By the end of the project, students will have customized their own playable 3D games and have gained a better understanding of scripting, variables, functions, and classes. 

Participating in the global Hour of Code? Visit our Hour of Code Edition of this Creator Kit.

No coding experience? No problem! In this beginner project, you’ll explore the basics of C# code for Unity in the context of an action RPG. 

To get the most out of this project, you’ll have completed one of the three introductory Creator Kits (Puzzle, FPS, RPG), so you can apply your knowledge of the Unity Editor and focus on customizing the game with scripts.

Important: This learning content requires at least Unity 2019.2, and will not work correctly on older versions.

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 Challenge: Create another potion at game start

Review the challenge solution

Review the function declaration

Review the function body

Using the function in a script

Adjust the behaviour of your function when it is called

Identify the function that already exists in your script

Tutorial summary

Unity HOC 1.3 Functions.mp4

Write code to create another health potion at game start

Learn about functions and their role in code 

Identify the function that’s in the SpawnerSample script already

When you’ve finished, you’ll be ready to write your own function.

Games

Hour of Code - Creator Kit: Beginner Coding

In the previous tutorial, you adjusted the SpawnerSample script to make it easy to adjust the distance at which three health potions spawn to help the moose.

Next, a challenge — can you work out how to spawn a fourth potion further away than the other three, using the code that you already have?

Use the following process to complete the task:


1.  In Unity Editor, go to the Project Window and select the SpawnerSample script at the file path Assets/Creator Kit - Beginner Code/Scripts/Tutorial.


2.  In the Inspector, click the Save State button. This will save a version of the script in its current form, in case you make changes that you don’t want to keep. 


If you need to, you can return to the Inspector at any time and select the Restore button to return the script to the previous version. 

3.  Modify your script to create four potions at game start. Don’t worry about breaking anything — you’ve copied your file, so you can always recover the previous state of your script.

TIP: Think about the position of the new potion bottle. Can you adjust an instruction to make the approach potion positioning consistent?



4.  Save your changes with Ctrl + S (Windows) or Cmd + S (macOS), then return to Unity Editor and test your changes in Play Mode.

5.  When you’ve finished checking your changes, Click Play again to exit Play Mode.

Continue to the next step to see the solution.

1.  Copy and paste the four lines of instructions which tell the computer to create a new potion at game start (to create four sets of the code in total):


angle = 95;
direction = Quaternion.Euler(0, angle, 0) * Vector3.right;
spawnPosition = transform.position + direction * radius;
Instantiate(ObjectToSpawn, spawnPosition, Quaternion.identity);



2.  Adjust the angle value in the fourth set of the code, to alter the position of the new potion:

// Fourth potion created at spawn
angle = 135;
direction = Quaternion.Euler(0, angle, 0) * Vector3.right;
spawnPosition = transform.position + direction * radius;
Instantiate(ObjectToSpawn, spawnPosition, Quaternion.identity);


In the version above, you’ll notice that there’s a description of the code preceded by a double forward slash (//). This is a comment. 

Comments are messages from the person writing the script to human readers; the compiler ignores everything preceded by the double forward slash. You can use comments to explain your code to others, or to write notes and reminders for yourself.


3.  When you test your game, it should look similar to this (depending on the exact angle you added in the fourth set of code):

This isn’t a very efficient way of writing code, though. If you wanted to create ten potions at game start, for example, you'd end up with a long script with a lot of repetition. If only there were a better way...

Luckily, there is something that can help you avoid writing lots of repetitive code: functions.

Functions are sets of instructions. When the compiler reaches a function, it will tell the computer to complete (or execute) all the instructions in that set before continuing with the rest of the script.

In the sample below, the computer needs to execute the function (2) before it can complete the rest of the sequential instructions in the script.

Let’s start by reviewing a sample function:

void AddingNumbers(float num1, float num2)
{
  float resultingNumber;
  resultingNumber = num1 + num2;
}

To work out what this function does, start by breaking down the first line: 

void AddingNumbers(float num1, float num2)


This is a function declaration, which instructs the computer to create a function. This is similar to a variable declaration. A function declaration always includes:

1.  The type of the function. void is a special type, which means “no type” or “empty” because it’s not stored anywhere. When you call an int function, it will return an integer value; void type variables don’t return values.


2.  The name of the function, which you will use every time you want the computer to execute the instructions in the function. The name of this function is AddingNumbers.

3. Variable declarations, between parentheses. These are called parameters. You can include as many parameters as you want, separated by commas. The parentheses are required even if the function takes no variables.

The variables are float type variables. Float variables are fractional numbers, as opposed to int variables (which are integers, or whole numbers). They have numbers on either side of a decimal point, and can be used for increased accuracy.

  Hover over the mortarboard icon to review another example of a float variable.

After the function declaration, there is:


Everything between those two curly braces is called the function body:

{
  float resultingNumber;
  resultingNumber = num1 + num2;
}

The function body contains the instructions that are bundled under the function name. The computer will execute these instructions when it encounters the function name in another instruction.

You don’t need to break down the instructions included in this example function. Just remember, each single instruction within the group ends with a semicolon.

Now that you’ve explored how functions work, you can use them in your own instructions. This is known as a function call.


Let’s explore the following example function call:

A set of parentheses containing two values

A semicolon, to mark the end of the instruction

Function calls tell the computer to execute all the instructions contained in the function before continuing to work through the script sequentially.

The script example you’ve reviewed in this tutorial declares two variables:

You can use this variable name in the function body like any other variable. You can also assign it a value whenever you call the function — this is called passing a value. 

If you write AddingNumbers(5.5f, 18.9f); to call the function, the computer will substitute 5.5 for the variable num1 and 18.9 for the variable num2 within the body of your function.


If you call AddingNumbers(10.0f, 10.0f); instead, the computer will substitute the variable names with 10.0 for all instructions in the body of the function. 

This enables you to write generic instructions inside your function, and adjust its exact behaviour each time it is called in your script.

Now that you know what a function is, you may have realized that there is already a function in the SpawnerSample script. All of the instructions that you have reviewed and adjusted so far are part of a function called Start.

Unity has specific functions with special names, that are called at specific moments in the game. Start is one of these special functions. As its name implies, the Start function is called when the Scene starts — that’s why the four health potions appear as soon as you press Play to begin the game.


Let’s review the Start function declaration:


This function has no parameters, but it still needs the parentheses ⁠— if these aren’t included, the compiler will think that void Start is declaring a variable named Start.

Saved the state of your SpawnerSample script in Unity Editor

Adjusted the script to spawn another potion at game start 

Learnt about functions and how they can be used to make code more efficient

Reviewed how to declare and call a function

Identified the function that’s in the SpawnerSample script already

Phew, that’s a lot! Now that you’ve explored the fundamentals, you’re ready to write your own function to spawn potions in the next tutorial.

For example, the following variable declaration included an example of the value a float variable could be used to store:

There are other variables which also store numbers with decimal points. When you assign a float variable, you need to add an ‘f’ after the value with a decimal point — this tells the compiler to read it as a float.

Introduction to functions

1. Challenge: Create another potion at game start

2. Review the challenge solution

3. Introduction to functions

4. Review the function declaration

5. Review the function body

6. Using the function in a script

7. Adjust the behaviour of your function when it is called

8. Identify the function that already exists in your script

9. Tutorial summary

Complete this tutorial