Introduction to real-time 3D experience design

Set up version control

Explore the sample project

Principles of object-oriented programming

Create a scene flow

Implement data persistence between scenes

Implement data persistence between sessions

Quiz: Manage scene flow and data

Submission: Data persistence in a new repo

Learn about data persistence and an introduction to the core pillars of object-oriented programming.

In this mission, you’ll learn about data persistence, or how to manage the loading and unloading of data between both scenes and sessions. Along the way, you will be introduced to the core pillars of object-oriented programming, which will help you structure your code throughout the mission. There will only be one practical example throughout the mission, which will build on the new functionality you create with each tutorial. At the end of this mission, you’ll take everything you learned and apply it to a new project by building a persistent score system for a small game.

Manage Scene Flow and Data

Unity Junior Programmer

Kickstart your programming career with Unity's Junior Programmer Pathway. Learn coding fundamentals, C#, and game development to create your first interactive projects. Start learning for free!

Junior Programmer Pathway - Learn Coding & Game Development | Unity Learn

We recommend that you have basic knowledge of Unity or complete 

Ready to code? This guided learning Pathway will take you from zero to job-ready!

Welcome to Junior Programmer! Designed for anyone interested in learning to code or obtaining an entry-level Unity role, this pathway assumes a basic knowledge of Unity and has no math prerequisites. Junior Programmer prepares you to get Unity Certified so that you can demonstrate your job-readiness to employers.

Junior Programmer

Course Introduction

Install Unity Software

Unit 1 - Introduction

Lesson 1.1 - Start your 3D Engines 

Lesson 1.2 - Pedal to the Metal

Lesson 1.3 - High Speed Chase

Lesson 1.4 - Step into the Driver's Seat

Challenge 1 - Plane Programming

Lab 1 - Project Design Document

Introduction to project management and teamwork

Quiz 1

Learn how to create new C# scripts, call basic functions, and use variables to modify the results of those functions.

In this first mission in the Junior Programmer pathway, you will program a car moving side-to-side on a floating road, trying to avoid (or hit) obstacles in the way. In addition to becoming familiar with the Unity editor and workflow, you will learn how to create new C# scripts and do some simple programming. By the end of the Unit, you will be able to call basic functions, then declare and tweak new variables to modify the results of those functions.

Player Control

Unit 2 - Introduction

Lesson 2.1 - Player Positioning

Lesson 2.2 - Food Flight

Lesson 2.3 - Random Animal Stampede

Lesson 2.4 - Collision Decisions

Challenge 2 - Play Fetch

Lab 2 - New Project with Primitives

Quiz 2

Mod the Cube

Quiz: Create with Code 1

Gain familiarity with some of the most important programming and Unity concepts, including if-then statements, random value generation, arrays, collision detection, prefabs, and instantiation.

In this Mission, you will program a top-down game with the objective of throwing food to hungry animals - who are stampeding towards you - before they can run past you. In order to do this, you will become much more familiar with some of the most important programming and Unity concepts, including if-then statements, random value generation, arrays, collision detection, prefabs, and instantiation. In completing this Unit, you will learn how to program a basic game with the ability to launch projectiles and maneuver the player to keep the game alive.

Basic Gameplay

Unit 3 - Introduction

Lesson 3.1 - Jump Force

Lesson 3.2 - Make the World Whiz By

Lesson 3.3 - Don't Just Stand There

Lesson 3.4 - Particles and Sound Effects

Challenge 3 - Balloons, Bombs, & Booleans

Lab 3 - Player Control

Quiz 3

Learn how to add music, sound effects, and visual particle effects to transform the experience of your project.

In this Mission, you will program a fast-paced endless side-scrolling runner game where the player needs to time jumps over oncoming obstacles to avoid crashing. In creating this prototype, you will learn how to add music and sound effects, completely transforming the experience of your projects. You will also learn how to create dynamic endless repeating backgrounds, which are critical for any side-scrolling games. Finally, you will learn to incorporate particle effects like splatters and explosions, which make your games so much more satisfying to play.

Sound and Effects

Unit 4 - Introduction

Lesson 4.1 - Watch Where You’re Going

Lesson 4.2 - Follow the Player

Lesson 4.3 - PowerUp and CountDown

Lesson 4.4 - For-Loops For Waves

Challenge 4 - Soccer Scripting

Lab 4 - Basic Gameplay

Quiz 4

Learn how to implement new gameplay mechanics including powerups and increasing difficulty.

In this Mission, you will program an arcade-style Sumo battle with the objective of knocking increasingly difficult waves of enemies off of a floating island, using power ups to help defeat them. In creating this prototype, you will learn how to implement new gameplay mechanics into your projects, which are new rules or systems that make the game more interesting to play. On one hand, you will learn to program a powerup, which give the player a temporary advantage. On the other hand, you will learn to program increasingly difficult enemy waves, which make survival more challenging for the player. A good balance of powerups and increasing difficulty make for a much more interesting gameplay experience.

Gameplay Mechanics

Unit 5 - Introduction

Lesson 5.1 - Clicky Mouse

Lesson 5.2 - Keeping Score

Lesson 5.3 - Game Over

Lesson 5.4 - What’s the Difficulty?

Challenge 5 - Whack-a-Food

Lab 5 - Swap out your Assets

Quiz 5

Introduction to user feedback and testing

Learn how to implement a User Interface - or UI - into your projects, such as a title screen and score display.

In this Mission, you will program a game to test the player’s reflexes, where the goal is to click and destroy objects randomly tossed in the air before they can fall off the screen. In creating this prototype, you will learn how to implement a User Interface - or UI - into your projects. You will add a title screen with a difficulty select menu that will control how challenging the gameplay is, you will add a score display that will track how many points the player has earned, and you will add a Game Over screen, which will allow the player to restart and try again. In learning these skills, you will be able to create a fully “playable” experience that the user can enjoy from start to finish without having to restart the application to try it again.

User Interface

Next Steps - Introduction

Lesson 6.1 - Project Optimization

Lesson 6.2 - Research and Troubleshooting

Lesson 6.3 - Sharing your Projects

ECS Survival Guide

Career research and preparation

Introduction to portfolios

Debug the App

Counting Prototype

Quiz: Create with Code 2

Prepare to continue developing your Unity and C# skills independently, including learning how to complete your personal project.

In this Mission, you'll prepare to continue developing your Unity and C# skills independently, including learning how to complete your personal project and how to prepare for the Unity Certified User: Programming exam, which you can take through your school program, if available.

Publishing Your Project

Abstraction in object-oriented programming

Inheritance and polymorphism in object-oriented programming

Encapsulation in object-oriented programming

Profile code to identify issues

Job preparation: Junior Programmer

Quiz: Apply object-oriented principles

Submission: Programming theory in action

Deep-dive into the pillars of object-oriented programming and their application, then learn how to profile and optimize code.

In this mission, you’ll refactor the inventory project you completed in the previous mission using the pillars of object-oriented programming as a guide. You’ll deep dive into the inner workings of each pillar individually, so you can better understand its value in developing applications. Next, you’ll learn how to profile your code to identify any optimization bottlenecks that would slow down the final build of your application. To close out this mission, you’ll develop a small application for your portfolio that uses fully optimized code built on OOP principles. 

When you complete this mission you will complete the Junior Programmer pathway - CONGRATULATIONS!

Apply Object-Oriented Principles

18c8af20-d74b-4c0f-913e-379040b0cab4:2ee3499ccba9

Overview

Review the required scene flow

Review the UI menu

Write a method to load the Main scene

Set the Menu scene index

Configure the Start button

Write a method to quit the application

Revise your method with conditional compiling

Add a new namespace

Challenge: Set up the transition back to the Menu scene

Next steps

In this tutorial, you’ll set up the scene flow between the Menu and Main scenes, and the exit flow for the application in the application. 

By the end of this tutorial, you will be able to:

Call the appropriate start-up methods in the initialization sequence of the app

Load the next scene when triggered by an event

Junior Programmer: Manage scene flow and data

As you reviewed in the previous tutorial, the application you’ll be working on in this mission has a number of different scenes that the user needs to navigate between.

Right now the application starts directly in the Main scene. In a real-world application, there would be a menu at the start of the application where the user could adjust settings or quit. In this tutorial, you’ll create that menu.

We’ve prepared a basic UI menu Canvas in the Main scene, but it doesn’t work out of the box. 

If you need to refresh your memory, take a moment to review the full scene flow overview in the project brief.

Let’s begin by setting up the application so that the user can:

Simple flow diagram detailing the app transitions, showing: the Menu scene launching on entry; two way transitions between the Menu and Main scene; exit from the Menu scene only.

Let’s review the UI Canvas that’s already been created for this project:

1.  If you haven’t done so already, open your project from the Unity Hub.


2.  In the Project window, go to Assets > Scenes and open the Menu scene.


3.  In the Scene view control bar, set the Scene view to 2D mode.

4.  In the Hierarchy, expand the Canvas and then the Container GameObject, which contains two more GameObjects: StartContainer and Exit.  

 5.  Expand the StartContainer GameObject. 

StartContainer contains four button GameObjects grouped together in the StartContainer section of the Canvas:

The menu isn’t functional yet, but you can still review the color selection buttons in action — let’s try that now.

6.  In the toolbar, select Play to enter Play mode. You’ll notice that there are now four color selection buttons available in the white rectangle.

The color selection buttons are controlled by the MenuUIHandler.cs script on the Canvas GameObject. This is a custom script that’s been written for this project. Right now, all it’s doing is initializing the color buttons. Let’s add two methods: one to start the Main scene and one to exit the application. 

There are four horizontal rows of buttons in the menu: the color buttons; Save Color and Load Color; Start; and Exit.

Let’s start by writing the method to load the Main scene from the menu:

1.  In the Project window, go to Assets > Scripts. Double-click MenuUIHandler.cs to open the script in your default IDE. You’ll find the following script prepared for you:

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// Sets the script to be executed later than all default scripts
// This is helpful for UI, since other things may need to be initialized before setting the UI
[DefaultExecutionOrder(1000)]

public class MenuUIHandler : MonoBehaviour
{
    public ColorPicker ColorPicker;

    public void NewColorSelected(Color color)
    {
        // add code here to handle when a color is selected
    }
    
    private void Start()
    {
        ColorPicker.Init();
        // this will call the NewColorSelected function when the color picker has a color button clicked
        ColorPicker.onColorChanged += NewColorSelected;
    }
}

2.  Under the Start method, add the following new method called StartNew: 

public void StartNew()
{
    SceneManager.LoadScene(1);
}

SceneManager is the class that handles everything related to loading and unloading scenes.

3.  Save your file, and return to the Unity Editor. 

Take a moment to review the Console. You may notice the following error message: “The name 'SceneManager' does not exist in the current context.” This occurs because SceneManager is grouped in a different namespace (that is, a different group of code) from the one included in this script file.

If you don’t see this error, your IDE might have added it automatically when you typed “SceneManager”. Follow the next steps to double-check that the namespace was added.

4.  Return to your script editor. The namespaces included in a script can be found at the top of the file in the lines starting with using. 

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

There are multiple namespaces in this script already. The line using UnityEngine;, for example, means that everything in the UnityEngine namespace (that is all classes you have used so far, such as Vector3 and Transform) can be used in this script file.

5.  Add the following namespace to the list in the script, and then save your changes: 

Now the SceneManagement namespace is included in this script and can be used in the scene. 

Next, let’s prepare to set up the Start button by setting the Menu scene index:

1.  Before you return to the Editor, take a moment to review the instruction that you wrote in your new method to load the scene: SceneManager.LoadScene(1);

The LoadScene parameter is a number, but what does this refer to? It’s the index of the scene that you want to load. You can define a scene’s index in the Build Settings window.

2.  In Unity Editor’s top menu, go to File > Build Profiles. A new window will appear, in the Platforms section select Scene List. This is where a scene’s index is set. 

3. Make sure both the Main scene and the Menu scene appear in the Scenes List menu. If either is missing, go to the Project window, navigate to the Scenes folder, then drag and drop the missing scene into the Scenes List section. The Menu scene needs to be above the Main scene in the list so that it has the lowest index value (0). If you need to, select and drag items in the list to change their order. 

The Scene List section; Menu is listed first with the index 0, Main is listed second with the index 1.

Now you’re ready to set up the Start button:

1.  In the Hierarchy, select the StartButton GameObject (which is a child of the StartContainer).

2.  In the Inspector, find the Button component.

3.  Find the On Click () property. This is where you can set the events that Unity will invoke when the user selects the button. Select Add (+) to add a new Event array.

4. Drag and drop the Canvas GameObject to the target field of the On Click event, underneath the Runtime Only drop-down, to assign it. 

The Canvas GameObject has the MenuUIHandler component attached.

5. In the Function dropdown menu, select MenuUIHandler > StartNew. 

6.  Save your changes, then go to the toolbar and select Play to enter Play mode. 

7.  Try selecting the Start button — you should find that it launches the Main scene! You won’t be able to get back from that scene for now. When you’re done, remember to exit Play mode. 

On Click event with the GameObject property assigned as the Canvas.

The Function dropdown in the On Click event set to MenuUIHander.StartNew.

Now, let’s set up the Exit button in the Menu scene:

1.  Return to MenuUIHandler.cs in your IDE.


2.  Under the StartNew method, add the following new method called Exit: 

public void Exit()
{
    Application.Quit();
}

The instruction calls the method to close an application: Application.Quit().


3.  Save and return to the Unity Editor, then test the Exit button in Play mode — does it work? Take a moment to consider why before reading on.

The button isn’t currently working because Application.Quit only works in the built application, not when you’re testing in the Editor. To make it work similarly there, you’ll need to use a special method to stop PlayMode. But how can you change the code to run different lines depending on where the application is running?

That’s where conditional compiling comes in. You can use conditional compiling to branch the code based on where the code is compiled — in the Editor, or for a build.

Revise your method using conditional compiling:

2.  Update your Exit method with the following code:

  public void Exit()
    {
#if UNITY_EDITOR
        EditorApplication.ExitPlaymode();
#else
        Application.Quit(); // original code to quit Unity player
#endif
    }

But what does this code mean? All lines starting with # aren’t really “code”. They won’t be compiled and executed — they’re actually instructions for the compiler. It is similar to code you’ve encountered before, though!

Let’s translate it into something a little more familiar:

if (UNITY_EDITOR)
{
    // run this code
}
else
{
    // run this code
}

Because this if conditional statement is an instruction to the compiler, the part that is not true will be completely removed. 

When the code is compiled inside the Editor then UNITY_EDITOR is true, it will keep the EditorApplication.ExitPlaymode() code and discard the Application.Quit.



When you build a player, UNITY_EDITOR will be false, and so it will keep Application.Quit() and discard EditorApplication.ExitPlaymode() !

If you return to Unity Editor, you may find a familiar error in the Console: “The name 'EditorApplication' does not exist in the current context.” 

Just like SceneManager, EditorApplication is in another namespace — this time, that namespace is UnityEditor, which is only available within the Unity Editor, so the fix is slightly different:

2.  Add the following code to the end of the list of namespaces: 

#if UNITY_EDITOR
using UnityEditor;
#endif

You’ve added conditional instructions to the compiler around the namespace: #if UNITY_EDITOR, so that the namespace will only be included when you are compiling within the Unity Editor.

If you didn’t add an if statement for the compiler, then when you tried to build a standalone player, you’d get an error that it can’t find UnityEditor. This is because it’s not included in a player build. (If you want to test this out, remove the conditional instructions and give it a go!)

When you create a build for a player, it will discard the line of code and won’t try to import the namespace. On the other hand, if you select Exit while testing in the Editor, it will exit Play mode. 

Now users can get to the Main scene and exit the application from the starting menu, but at the moment they can’t get back to that menu from the Main scene.

We’ve created a Back to menu button in the Main scene, but you’ll need to get it working yourself. 

You can find the GameObject for the button in the Canvas GameObject.

The Canvas GameObject has the UI Main Scene (Script) component attached — this handles the UI in the Main scene.

You can review the process you followed in Configure the Start button if you get stuck.

Test your changes in Play mode to make sure they work properly.

Now you’ve connected your scenes to the UI to meet the mission brief! But there’s something missing —  the color selection buttons still don’t work

In the next tutorial, you’ll add this functionality by implementing data persistence.

If our pre-created menu is a little boring for your taste, don’t despair — you can customize the appearance of the default menu, or create your own from scratch! This is a great opportunity to consolidate your work in Create with Code Unit 5 - User Interface.

Create a scene flow

1. Overview

2. Review the required scene flow

3. Review the UI menu

4. Write a method to load the Main scene

5. Set the Menu scene index

6. Configure the Start button

7. Write a method to quit the application

8. Revise your method with conditional compiling

9. Add a new namespace

10. Challenge: Set up the transition back to the Menu scene

11. Next steps

Complete this tutorial