Learn C# for Unity: A Comprehensive Guide

Unity is a versatile 3D development platform used for creating video games, architectural visualizations, medical imaging, and more. While Unity offers immense creative potential, its complexity can be daunting, especially for beginners in coding and game development. This guide provides a structured approach to learning C# for Unity, suitable for various skill levels, from novice to experienced developer.

Introduction to Unity and C

This guide is designed to help you get started with Unity and C#, even if you have no prior experience. It will walk you through the fundamentals, gradually building your knowledge to a solid working level.

Course Overview

This course will teach you how to program your own exciting projects from scratch in C#. You will learn how to iterate with prototypes, tackle programming challenges, complete quizzes, and develop your own personal project. By the end of the course, you will have the confidence that you can Create with Code.

Key Skills Covered

Variables and Data Types: Understanding and using variables to store and manipulate data.
Collision Detection: Implementing collision detection to create interactions between game objects.
If Statements: Using conditional statements to control the flow of your code.
Forces: Applying forces to game objects for realistic physics-based movement.
Namespaces and Classes: Organizing your code using namespaces and creating reusable components with classes.
Arrays: Storing and managing collections of data using arrays.
For Loops: Iterating through arrays and other data structures using for loops.
Coroutines: Implementing asynchronous operations using coroutines.
Lists: Using dynamic collections of data with lists.
Pickups: Implementing collectible items in your game.
Animations: Creating and controlling animations for your game objects.
Post-Processing: Enhancing the visual quality of your game with post-processing effects.
Nav Mesh Agents: Implementing AI-controlled characters that can navigate the game world.
Enemy AI: Creating intelligent enemy behavior.
Weapon Switching: Allowing the player to switch between different weapons.
Raycasting: Detecting objects in the game world using raycasts.
ProBuilder: Prototyping levels quickly using ProBuilder tools.

Project-Based Learning

This course is project-based, so you will be applying programming concepts immediately to real indie games as you go. All the project files will be included, as well as additional references and resources.

Game Projects

Obstacle Dodge: Learn player input, collisions, variables, and if statements.
Rocket Boost: Learn about forces, namespaces, and classes.
Galaxy Strike: Master Unity's terrain and timeline tools while coding arrays, for-loops, and coroutines.
Royal Run: Build worlds that never stop, use lists, pickups, animations, post-processing, and more.
Sharp Shooter: Tackle nav mesh agents, enemy AI, weapon switching, raycasting, and prototyping levels with ProBuilder.

C# Fundamentals

The C# guide contains articles, tutorials, and code samples to help you get started with C# and the .NET platform. Experienced developers can learn about new features in the What's new section. Read C# language reference material, and the C# language specifications. The C# reference provides an informative reference for the C# language. The C# language specification is the normative reference for the C# language. It's the official source for C# language syntax and semantics.

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Setting Up Your Environment

Download Unity: Unity is a free download. With regular access to an internet connection you'll be able to engage in our thriving community.
Install Visual Studio Code: Make sure you go into Edit - Preferences and select your IDE as the external tool.

Importing Assets

Import the visual assets that we're going to use in the course. These include some Meshes for all the Counters, a bunch of Textures, Animations, Sound Effects and Music.

Post Processing

In this lecture we're going to set up Post Processing to make our game look good. This is actually something that I normally only do later on in the development process but since this course is in a video format I decided to set it up right away just to make the video more appealing.

Troubleshooting Post Processing Issues

Make sure that you have your project set up to use the Universal Render Pipeline. If you're using the older Built-In Render Pipeline the Volume component won't do anything.

Character Controller

Let's begin writing some code by learning how to make a simple Character Controller.

Troubleshooting Code Issues

Make sure the Player script is named exactly Player both on the filename and the class name.
Make sure Update is written exactly Update, not update or upDate or anything else.
Make sure the script is attached to the Player game object, make sure that game object is enabled.
Make sure the script extends MonoBehaviour.
Look at your console and make sure the Collapse button is untoggled.

Understanding Vector Magnitude

It's essentially the size of the Vector, if you picture a Vector2(1,0) and you picture an arrow pointing right, the size of the arrow will be 1. If you picture a longer vector, like a Vector(2,0) it will be longer and have a magnitude/size of 2. Normalizing the Vector means keeping the same direction but setting the magnitude to 1.

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Time.deltaTime

That field contains the number of seconds elapsed since the last frame was rendered. So if the game is running at 10 FPS then that field will have 0.1, meaning every frame takes 0.1 seconds to render so 10 frames render in 1 second. By using it in the calculation you are making sure the character movement is based on time regardless of framerate. If the game is running at 10 FPS then the character will move 0.1 units per frame so it will move 1 unit in 1 second. If the game is running at 50 FPS then the character will move 0.02 units per frame so it will move 1 unit in 1 second.

VSync

It's a setting which will make your game render as fast as your monitor's refresh rate (if the GPU can handle it) So if you have a 60Hz monitor and VSync is enabled the game will run at most at 60 FPS and never higher.

Public vs. Private Variables

When you make a variable public you are enabling both READ and WRITE access from anywhere. So if you have 1000 classes that means you have 1000 possible places that could be modifying that variable. Whereas if you keep it private it doesn't matter how big is your codebase, only the code in that class can access that field. Writing good clean code is all about minimizing complexity and the more you limit access to your fields/functions/classes the fewer things you need to keep in mind while writing code. Definitely check out the related video for more detail, following this one simple rule will massively increase the quality of your code.

Debug.Log vs. Print

The answer is simply personal preference. One difference is 'print' only exists within a MonoBehaviour, so if you have a regular C# class it won't know what is 'print' whereas 'Debug.Log' works everywhere.

Transform.position vs. Transform.Translate()

The answer is, there's no specific reason, both do the exact same thing. So you can use whatever option you prefer, both will achieve the same result.

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Transform and CapsuleCast vs. Rigidbody and Collider

As usual in many things related to Game Development there are always a multitude of options to achieve the same result.

Material Rendering

Remember that the rendering is per Material. Meaning if two objects share the same Material and you modify that Material it will change both objects. If you want two objects to have different visuals you need to use different Materials.

Lerp vs. Slerp

Slerp works just like Lerp except instead of treating the Vectors as normal Vectors (which can increase or decrease in size), it treats them as Directions. For example if you use Lerp and you Lerp from (1, 0) to (-1, 0) then essentially you want the character to do a 180 rotation. But if you use Lerp it will interpolate by first 'moving' the vector towards (0, 0) before it suddenly flips.

Legacy Animation System

This is the Animation System that Unity used before version 3. It's very simple, it literally just plays animations, there is no state machine. Nowadays you should probably be using the Mecanim Animation System, it features an Animation Controller which is a State Machine which makes it much simpler to handle various states and transitions between them. Although the Legacy Animation System can still be useful if you're doing some extremely simple animation with no transitions and no other states. You can swap between both types by selecting the Asset in the Project Window and then setting the Inspector to Debug Mode and toggling/untoggling the Legacy field.

Animation Exit Time

If this is enabled then the transition will happen automatically when the previous animation completes. If disabled it will never automatically trigger the transition

Why Strings are Bad for Identifying Things

They are very brittle, it's very very easy to make a mistake. 'Walking' is not the same as 'walking' and not the same as 'waIking' and not the same as 'walking 'It's very easy to make a small typo like that and at a glance it's very difficult to see. As far as the code is concerned all of those are variable strings so there's no compilation error which makes debugging such problems very difficult.

Cinemachine

Cinemachine works on top of the Camera. The Camera will have a CinemachineBrain component and that component will set all the fields on the Camera based on the active Cinemachine Virtual Camera.

Perspective vs. Orthographic Camera

The answer is personal preference.

Input Manager

Personally I find that they both have their use cases. The new Input System is excellent and very feature rich, this is definitely the system you should be using in your final shipped build. However for quickly prototyping the Legacy Input Manager is just so much simpler. So personally I tend to use them just like I showed in this course, first I make a quick prototype using the Legacy Input Manager, and then later on in the development process I convert it to use the new Input System.

Refactoring Code

Refactoring/rewriting code is not a bad thing at all, it is something you should always do when needed, so that's why on this course I wanted to emphasize that point. I did that to show you exactly how game development is really like.

BoxCast vs. CapsuleCast

Yes, you can use any shape you want, for a player controller either of those can work well.

Overlap Functions vs. Cast Functions

The Overlap functions only test if there is another collider on that target area. Whereas the Cast functions 'move' a shape through the Physics world and check if there's anything on the way to the target area. For example if you have PositionA and then PositionB far away and inbetween the two is a wall.

C# Events

Let's learn about C# Events which are one of the most powerful C# features. This is one of the most essential things you need to know if you want to learn how to write good high quality clean code.

Function Signature

Function signature means the function return type, the number of parameters and type of parameters. Importantly the name of the function is not part of the signature. So a function 'private int MyFirstFunction(string name, float value)' has the exact same signature as 'private int MySecondFunction(string name, float value)'

EventHandler

No, you can use any Delegate type you want, EventHandler is simply the C# standard so in order to make your code easier to understand for other programmers you should probably stick with the standard but you're not forced to.

EventHandler vs. Action

Same reason as previous, you can use any delegate type so yup you can use Action. The reason to use EventHandler is to stick with the standard.

Null Conditional Operator

It's the Null Conditional Operator

Unsubscribing to Events

It depends on the lifetime of the objects. If both publisher and subscriber have the same lifetime you don't have to manually unsubscribe.

Rendering Bugs

If two objects are on mathematically exact coordinates then the Graphics Card doesn't know which one should be rendered on top, so if that happens you will see flickering as the GPU tries to guess to render one or the other. If you see flickering just move/scale one object a tiny bit, just enough so it's not mathematically exact.

Singleton Pattern

The Singleton pattern is a tool and as with any tool it can be used or it can be abused. So whether it's good or bad depends on how you use it. When people say it is bad they are usually refering to the fact that if you use singletons all over the place you usually end up with tons of interlocked references all over the place. ClassA access the singleton of ClassB which in turn requires the singletons of ClassC and ClassD to exist. However that scenario is more a fault of the architecture of how all those classes are set up rather than the pattern itself. You should always minimize connections between classes as much as possible, you should focus on writing good clean code that is as decoupled from everything else as possible. you should focus on that regardless if you're using singletons or not. So don't be afraid of using the Singleton pattern (or any pattern), always keep in mind the general clean code guidelines regardless of whatever pattern you use.

Additional Resources

Unity Learn: Discover free learning experiences by Unity experts to take your real-time 3D skills to the next level.
Unity User Manual: Installation guides, term definitions, feature lists, and more to help you learn to use the Unity Editor, runtime, and associated services.
Unityâs best practices: Essential tips and guidelines for Unity creators at beginner, intermediate, and advanced levels, tailored across industries.

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