Learn C# Scripting for Unity in 15 Minutes (2024 Working)

Summary

In this Unity tutorial by Raja from Charger Games, viewers are guided through basic C# scripting techniques in Unity within 10-15 minutes. The video covers essential topics such as object destruction, keyboard and mouse input handling, physics integration with rigidbodies, collision detection, and loading new scenes. Additionally, it demonstrates how to display text on screen and control game objects using arrow keys. The tutorial is fast-paced, offering practical, step-by-step instructions to help users quickly grasp Unity scripting fundamentals.

Takeaways

• 🚀 The video focuses on learning C# scripting in Unity within 10-15 minutes, using a 3D cube as the example.
• 📦 Start by creating a C# script, attaching it to the cube, and learning the basics of the Start and Update functions.
• 💥 The Destroy function can be used to remove the game object immediately or after a delay, such as 3 seconds.
• 🖱️ The OnMouseDown function allows you to destroy the object when clicked with the mouse.
• ⌨️ You can also use keyboard inputs, such as pressing the spacebar, to destroy the object using the Input.GetKeyDown function.
• 🏀 Physics in Unity is demonstrated by adding a Rigidbody component to the cube, allowing it to react to gravity.
• 💨 Rigidbody forces, like AddForce, can make the cube jump or move by pressing keys, adding velocity in specific directions.
• 🔄 Collisions with other objects can be detected using the OnCollisionEnter function, which checks the object's tag and triggers actions like destroying an object.
• 🎮 Scene management is introduced, where pressing a key like 'R' loads a new level or scene in Unity using SceneManager.
• 📝 Text elements, such as displaying 'You Win' on collision events, are also covered using Unity's UI system and GameObject.SetActive.

Q & A

What is the purpose of the 'Start' and 'Update' functions in Unity scripts?

The 'Start' function is called at the start of the game when the game begins, while the 'Update' function is called repeatedly every single frame.

How can you destroy a game object in Unity using a script?

You can destroy a game object by calling the 'Destroy' function with the game object as its argument, typically within the 'Start' or 'Update' function.

What does the 'OnMouseDown' function do in Unity scripts?

The 'OnMouseDown' function is called when the object with the script attached is clicked with the mouse.

How can you make a game object respond to keyboard inputs in Unity?

You can use the 'Input.GetKeyDown' method to check if a specific key is pressed and then perform an action, such as destroying the object, in response.

What is a Rigidbody component and how does it affect a game object in Unity?

A Rigidbody component makes a game object part of Unity's physics engine, allowing it to have mass and be affected by gravity and other forces.

How can you add force to a game object in Unity to make it move?

You can add force to a game object by accessing its Rigidbody component and calling 'RB.AddForce' with a Vector3 direction and a force amount.

What does the 'OnCollisionEnter' function do in Unity scripts?

The 'OnCollisionEnter' function is called automatically when the game object collides with another game object, allowing you to perform actions based on the collision.

How can you detect if a game object has collided with a specific tag in Unity?

You can check the tag of the colliding object within the 'OnCollisionEnter' function using 'collision.gameObject.tag' and compare it to the desired tag.

What is the process to load a new scene in Unity when a certain condition is met?

To load a new scene, you can use the 'SceneManager.LoadScene' function with the scene name as its argument after ensuring the scene is added to the build settings.

How can you display text on the screen in Unity using UI?

You can create a UI Text element, position it, set the text properties, and then activate or deactivate it using script by setting the 'SetActive' property to true or false.

What is the role of the horizontal and vertical axis in controlling game object movement in Unity?

The horizontal axis typically corresponds to left and right arrow keys, while the vertical axis corresponds to up and down arrow keys. You can use these axis values to control the movement of a game object.

Outlines

00:00

🎮 Introduction to C# Scripting in Unity

Raja introduces the video, explaining that viewers will learn C# scripting in Unity in a short span of 10-15 minutes. He quickly walks through setting up a basic Unity project, where a cube object is selected for scripting experiments. The script includes two main functions: `Start` and `Update`, where the former is executed at the start of the game, and the latter runs every frame.

05:00

🛠️ Object Destruction and Time Delays

Raja demonstrates how to destroy a game object in Unity using the `Destroy` function. He shows how to set an object to be destroyed immediately when the game starts or after a specified time delay (e.g., 3 seconds). The tutorial covers how to modify the script to destroy the object either at game start or based on user input, such as mouse clicks and keyboard presses.

10:02

🚀 Applying Physics and Adding Forces

Raja explores Unity's physics engine, focusing on adding physical properties like gravity to a cube object by attaching a Rigidbody component. He walks through scripting the cube to react to user inputs, such as pressing the spacebar to apply a force that makes the cube jump upward. He also explains how to add velocity to the cube to move it in a specific direction and introduces collision detection by attaching an enemy tag to objects.

15:03

🌐 Scene Management and UI Elements

Raja covers Unity's scene management system by showing how to load different scenes (or levels) based on user input, such as pressing the 'R' key. He explains how to use UnityEngine's `SceneManagement` class to switch between scenes and demonstrates adding UI elements, like a win text that activates when certain conditions are met, such as collision detection between objects.

Keywords

💡C# Script

A C# script is a file written in the C# programming language, commonly used in Unity to control game objects and define behavior. In the video, the speaker creates a C# script called 'test' and attaches it to a cube object to demonstrate various actions, such as destroying the object or adding forces to it.

💡Unity

Unity is a popular game development platform that allows developers to build 2D and 3D games. The entire video is based on using Unity to create and manipulate game objects through scripting in C#, covering key concepts like physics, input handling, and scene management.

💡GameObject

A GameObject in Unity is the fundamental object in a game scene, representing characters, items, and other interactive elements. In the video, the speaker attaches the 'test' script to a cube GameObject to show how to manipulate and interact with it using various C# functions.

💡Destroy Function

The Destroy function in Unity is used to remove a GameObject from the scene, either immediately or after a specified time. The video demonstrates how to destroy a cube when the game starts, after a delay, or when clicking on the object using this function.

💡Start and Update Functions

These are two key Unity functions. The Start function is called once at the beginning of the game, and the Update function is called every frame during gameplay. The speaker explains how these functions are used to execute code, like destroying the cube at the game’s start or detecting input during gameplay.

💡RigidBody

A RigidBody is a component in Unity that allows GameObjects to interact with the physics engine. The video covers adding a RigidBody to the cube, which enables gravity and lets the cube fall, demonstrating how physics affects objects in Unity.

💡Input Class

The Input class in Unity is used to detect user input from devices like the keyboard or mouse. In the video, the speaker explains how to use this class to destroy the cube when pressing the spacebar or clicking on it, showcasing how user actions can influence game objects.

💡AddForce

AddForce is a Unity function that applies a force to a RigidBody, which can move or accelerate the GameObject. The video demonstrates how to use AddForce to make the cube jump when pressing the spacebar, by applying an upward force.

💡Collision Detection

Collision detection in Unity checks when two GameObjects with colliders come into contact. The speaker shows how to detect collisions between the cube and other objects like a sphere and how to execute actions (like destroying the sphere) when collisions occur.

💡Scene Management

Scene management refers to loading and unloading different game levels or scenes in Unity. The speaker explains how to use the SceneManager class to load a new level when the player presses the 'R' key, helping illustrate how to transition between different game environments.

Highlights

Introduction to Unity scripting in C# with a quick project setup.

Explaining the default 'Start' and 'Update' functions in Unity scripts.

Using the 'Destroy' function to remove objects in Unity, with a demonstration of immediate destruction upon game start.

Modifying the 'Destroy' function to delay object destruction after a specified number of seconds.

Implementing mouse click detection with the 'OnMouseDown' function to destroy an object when clicked.

Using keyboard input detection to destroy an object when the spacebar is pressed, using 'Input.GetKeyDown'.

Adding physics to the cube using a Rigidbody component, enabling gravity for realistic movement.

Adding an upward force to the cube when the spacebar is pressed, demonstrating basic physics manipulation with 'AddForce'.

Using Rigidbody velocity to move the cube in the forward direction continuously, with adjustments to prevent unwanted rotation.

Detecting collisions with the 'OnCollisionEnter' function, and destroying an object tagged as 'enemy' upon collision.

Demonstrating how to destroy the colliding object (a sphere) instead of the player’s object (the cube) upon collision.

Loading and switching between scenes with 'SceneManager.LoadScene' triggered by pressing the 'R' key.

Displaying a 'You Win' text element on the screen after a successful collision event using Unity's UI system.

Moving the cube left and right using arrow keys, adding force in the horizontal direction with 'AddForce' based on user input.

Wrapping up with suggestions for further learning and promoting additional Unity courses for deeper knowledge.

Transcripts

hello this is Raja from charger games

and welcome back to another new video so

in this video we're gonna learn about si

shop scripting in unity in just 10 to 15

minutes so this is gonna be fun let's do

this

alright so I'm gonna go really fast

because we have to cover a lot of things

in this short time so let's do this so

here I have a 3d project opened and I

have a cube right here and we're gonna

do all our experiments on this cube only

so here I have a scripts folder inside

that I'm gonna right-click and create a

new C sharp script I'm gonna simply name

this one test then I'm gonna go ahead

and select my cube and drag and drop the

test script on the cube then double

click to open it in Visual Studio so

here our script has been opened so first

things first we have these two functions

created by default the start function

and the update function the start

function gets called at the start of the

game when the game starts and the update

function gets called again and again and

again every single frame all right so

the first thing we're gonna do is we're

gonna learn to destroy the object so in

order to destroy the object we have a

function called destroy that you can

call from anywhere so we're gonna call

it from the start so we're gonna write

destroy and what are you gonna destroy

we can destroy this game object with

which the script is attached so you can

write game object exactly like this not

in capitals game object in small capital

like this so now we are calling it from

the start so it should get destroyed as

soon as the game starts so if I save the

script and go back to unity now let's

click on play and when the game starts

as you can see the cube cut' destroyed

all right so destroy function is working

so let's open the script again now we're

gonna learn to destroy it after a few

seconds so to do that we're gonna write

a comma and give the amount of time I

want to destroy it after so let's say

when we destroy up to three seconds I'm

going to write 3 F and if you want to

say float unit write F so we're gonna

destroy it after three seconds so in

unity we can play and then wait for 3

seconds 3 2 1 boom and as you can see in

3 seconds it get destroyed so that code

is working alright so destroy code is

working now let's learn how we can

destroy it by clicking on it to do that

here we're going to create a new

function we can

it void on Mouse down all right so this

function gets called when we click on

the object with our mouse alright so

here what I'm gonna do is we're gonna

comment this out by writing this double

slash that means this code is not

working anymore

and we're gonna simply copy this paste

it here and remove the 3f from here so

now whenever we will click our mouse on

the object or the cube it should get

destroyed so let's save the script by

pressing ctrl s and here let me go ahead

click on play now let me click on it and

as you can see as soon as I click on it

the cube gets destroyed click and it

goes destroyed so our mouse click is

working alright so now let's learn how

we can do that by using our keyboard

inputs so in order to use keyboard

inputs

first of all let's learn how to take

keyboard inputs to the keyboard inputs

we need to use the input class okay and

so we're gonna say if input dot get key

down key code dot space all right so

here we are pretty much saying that if

we press the space button on our

keyboard then what you want to do we

want to do this going to destroy the

object so let's copy it paste it right

here all right so now our update will

check every frame if we are pressing the

space button and then it will destroy

the game object now click on play and

three two one space and it got destroyed

so as soon as I press the space button

it gets destroyed now let's learn to use

some physics properties in the project

so here I'm gonna select the cube go to

add component and go to physics and from

here I'm gonna add a rigidbody component

so now it's part of unity physics engine

and as you can see it uses gravity so it

has gravity now so if I click on play

and move the cube upwards as you can see

it automatically falls down due to

gravity so now we can use this rigid

body and do anything we want with

unities physics engine and here we're

gonna create a new public variable not

public just rigidbody RB and inside

start begin a write our V equals get

component rigidbody so here we are

pretty much getting access to the

rigidbody that we

attached to our game object so now we

can do anything that we want just by

using this RB variable so in the update

instead of destroying it let's add a

force to our game object so here we

gonna comment it out and now we're gonna

write whenever we press the space button

we want to say RB dot and force and what

do you want to add force we want to add

force in the upwards direction so for

that we're gonna write vector three not

up and how much you wonder at fourth

let's say five hundred amount so we want

to add a force of 500 amount in the

upwards direction to our object whenever

we press the space button so let's save

this click on play and let's press the

space button and as you can see as soon

as I press the space but in our cube

jumps because we are adding a force to

it okay so now let's add a velocity to

our cube to move it in a particular

direction so in this case we can move

our cube in the forward direction to do

that what I'm gonna do is I'm gonna

comment this cut out and now here I'm

gonna insert the update function I'm

going to simply say RB dot velocity so

we are adding a velocity to a rigid body

and we're gonna add a velocity in the

forward direction so we're gonna say

vector three dot forward I multiply it

by let's say 100 F oh let's say 20 F so

we are adding a velocity of 20 in the

forward direction so we're gonna save

the script so now if I click on play you

will see how cube moves in the forward

direction by this amount and as you can

see it's already rotating so we don't

want it to rotate so we gonna come to

our cube come to the rigidbody

and go to the constraints and click on

freeze rotation on the x-direction all

right so now if I click on play you will

see our cube is not rotating anymore

okay so now let's learn to detect

collisions with other game objects in

order to detect collisions we have a

function void on collision enter ok and

now inside this collision variable we

have all the information about the

object with which we have collided so

here we gonna check if collision that

game object dot tag equals enemy so that

pretty much means if the object with

which we have collided has an enemy tag

attached then we can simply destroy our

game object so this

function gets called automatically

whenever our game object gets collided

with any other game object then it will

check if the game object has an enemy

tag attached then it will destroy our

own game object so let's save this and

go back to unity so here I'm gonna

create a new 3d object sphere and I'm

gonna put the sphere upwards then I'm

gonna add a rigidbody to it physics

rigidbody so now it has a gravity as

well and it has this sphere Collider as

well and now I'm gonna go to these tags

click on app tag click on plus and add

an enemy tag okay then again I'm gonna

come to the sphere select the enemy tag

from here so now it should detect

collision so now if I click on play the

sphere falls down it collides with the

cube and before that our cue moves so so

before testing this we need to comment

out this line of code so now things

should be fine so here we are back

inside unity I'm gonna click on Play the

sphere falls down onto the cube and as

you can see as soon as it falls down the

cube gets destroyed because the cube

gets collided with an object which has

the enemy tag attached so our collisions

are working so now instead of destroying

the cube we're gonna destroy the sphere

whenever it collides with the cube so

let's see how we can do that so here we

are back inside our script so here we

are checking if our object is colliding

with an object which has the enemy tag

attached then we are destroying our own

game object so now we need to modify the

code and instead of this let's copy this

and paste it right here and comment out

this line of code so now instead of

writing game object we're gonna write

collision daaad game object okay just by

writing this simple code instead about

cube now the sphere will get destroyed

now let's click on play and three two

one boom instead of destroying the cube

this time the sphere gets destroyed

because we have written the code in a

different way okay so now let's learn to

reload or load a new scene or new level

in our game so if you go to file bill

settings you can see currently we don't

have any scenes in the build so let's

click on add open scenes so our first

scene isn't the build we need to create

another new scene to learn this

now we're gonna go to a file new scene

then press ctrl s to save this and you

can save it inside the scenes folder and

we're gonna name this level 2 then click

on save

so now we have a new level now we're

gonna go to the scenes folder and go

back to our level go back to our game

level and we're gonna open our script so

here inside the script we're gonna say

if we press the R then we're gonna go

back to our next level okay to check

that here we gonna say if input dot get

key down key code dot R if we press the

Add button then you want to reload the

next level now in order to load the next

level here we need to import a new thing

or use a new name space we need to write

using unity engine dot scene management

ok so just by writing this code now we

will be able to use all the scene

management related functions so now here

when to write scene manager not load

scene and which scene we want to load

with in quotations when it ride level 2

and then a semicolon so now whenever we

press the our key our scene manager will

load the level 2 level in our scene so

let's save this and go back to unity now

this is the most important step you need

to go to file build settings and click

on add open scenes we have only once in

here let's go to our scenes and drag and

drop the level 2 and put it here

so both of these scenes should be here

before we can actually load them so now

if I click on play it goes down the

queue gets destroyed I'm gonna press R

and as soon as I press the are the new

levels got loaded so as you can see this

way we can load a new level just by

pressing a key now let's go ahead and

learn to display a text on the screen so

here I'm gonna go to UI and create a new

UI text element I'm gonna go to reset to

reset its position at the center then

I'm gonna go and change the text to you

win I'm gonna go to go and select the

direct selection tool and double-click

on the text then I'm gonna make it then

I'm gonna go to the 2d mode and make it

bigger something like this then I'm

gonna go and change the font size and

make it big

and then I'm gonna change the text color

to white put it on the center something

like this now we have our text let's

name it to win text okay now let's go

back to our script so here first of all

we need to create a public variable

public gameobject

win text and now whenever our Spirit

collides with the cube we want to we

want to actually show the Windex

so whenever our spirit collides with

cube first of all you're gonna destroy

the sphere and then I'm gonna say win

text not set active to true so before

starting the game we're gonna deactivate

the win text and when the game starts

and when it collides with the game

object we're gonna set it to true so

that it shows up on the screen so save

these and go back to unity in the

beginning we need to set the wind text

and disable it select our cube go to the

script as you can see it is waiting for

a reference to the wind text we can a

drag and drop our wind text right here

so now it has got access to it now we

can a click on play and as you can see

when it will come and destroy it our

wind text will be displayed so this way

we know how to check collisions and

whenever how to actually activate or

deactivate an object when some event

happens ok so the last thing we're gonna

learn is how to move our cube left and

right by pressing the left and right

arrow keys so here we gonna create two

new variables float X input float Z

input and we gonna create another

variable public float speed okay so now

inside the update we gonna say X input

equals input dot get axis horizontal and

Z input equals input dot you get access

vertical so we get a value from the

horizontal axis when we press the left

and right arrow keys we get a value from

the vertical axis when we press that up

and down arrow keys now here we gonna

say our B dot add force and

addforce in our three different

directions so in the x-direction we can

add a four sub X input fix input

multiplied speed in the y direction

we're not going to add any force so make

0 in the Z we're gonna add a 4 so we're

gonna say the input multiply speed

alright

so now just by writing this simple code

a force will be added in the X direction

and in the Z direction to our cube game

object whenever we press the left and

right arrow keys so now save this go

back to unity here we can select our

cube and as you can see it is waiting

for a speed value let's give the value

of 2 for now let's go to click on play

and if I press the left arrow key okay

so first of all if I press the left

arrow key our cube should move left so

let's go ahead and turn up the value of

the speed I'm gonna make it about

hundred let's say now if I click on play

you will see all these things happen now

if I click on left our key moves to the

left and it automatically rotates so in

order to stop that we're going to go to

our constraints and click on freeze

rotation on x y&z three of these now if

I click on play if i press left it moves

to the left if i press right it moves to

the right so now as you can see our cube

10 to the left and right and if you want

you can go ahead and adjust the speed

value I'm gonna make it 50 let's say now

if I click on play it should work fine

so now as you can see it gives a better

player controller

setting so now is as you can see I can

move our cube left and right just by

pressing the left and right arrow key on

our keyboard so thank you so much for

watching this video I hope you really

enjoyed by learning c-sharp unity

scripting in this short amount of time

so if you want to learn more you can

check out all my courses from the links

in the description below and check out

my other videos as well so thank you so

much for watching this is Raja from

charger games and I'm gonna see you in

the next videos