Let's get started with the basics of what a game engine is and the different categories of games.

Intro & Getting Started

Learn about the characteristics of 2D and 3D games

Intro to 2D and 3D games

A brief introduction to the different game genres and what differentiates them.

Game genres

An introduction to the different moving parts of game development such as design, development, music, testing and release

Game development overview

Set up Unity hub on your computer and download Unity engine

Set up Unity hub

Let's make a new Unity3D project and get started with making our game

Make a new Unity3D project

Let's download a code editor called Visual Studio Code to write our code in.

Download Visual Studio Code

Introduction

Navigate and get acquainted with the different parts the Unity editor such as the project, inspector, hierarchy windows. We will also go over the different types of views (scene and game) and, learn how to customize the Unity editor.

Unity editor basics

Navigate and get acquainted with the different parts the Unity editor such as the project, inspector, hierarchy windows. We will also go over the different types of views (scene and game) and,  learn how to customize the Unity editor.

Navigating the Unity editor

In this section we'll go over what the different buttons of the toolbar can do.

Menu toolbar

The _project window_ will display all the assets used in your project, for example any music, images, 3D models and anything else related to your project.

Project window

The hierarchy window lists every game object in the current scene. We will navigate the hierarchy window, and learn about parenting, a concept which demonstrates the parent-child relationship between objects.

Hierarchy window

We will spend a lot of time in the inspector window which shows all the knobs and dials for our objects.

Inspector window

A unity package is a collection of files and components that is wrapped up into a single file. Unity packages have a `.unitypackage` extension.

Packages

An overview of the different types of views offered by the Unity editor and the camera object.

Scene view, game view and cameras

Test your game as a user would play it with the play, pause and stop buttons.

Play, pause and stop buttons

Learn how to cuztomize the placement of different windows in the Unity editor.

Customizing the Unity editor

In this module we will start building the game world for our game. We will go over importing assers, organizing our project and inspecting objects. We will also learn about concepts such as textures, materials and prefabs.

Building the map

Let's import all the assets that we need into our game and go over what we imported.

Import game assets

Discover what is meant by the term assets and organize the assets in your game.

Organize your project

GameObjects are the building blocks of a game scene whereas, a component defines a GameObject and its functionalities.

Unity GameObjects and components

Design aspects such as textures, materials and models are often neglected in game dev courses as these topics have more to do with design than development or game mechanics, but they can be specialized topics of their own. In this module we will give a brief explanation of models, materials and textures.

Textures, materials and models

You'll often hear the term prefab during game development, so let's go over what this means. Prefab is short for _pre-fabricated_. Prefabs are pre-configured game objects that you can store and use in your game.

Prefabs

In this short and simple section we will go over how to inspect GameObjects

Inspect GameObjects

In this module we will be building our game world! It will be a fully hands-on module and by the end you will have a general sense of the game surroundings in which your character will interact with other characters and live their life - the environment in which they'll grow flowers, eat snacks, wander around and nap.

Building the game terrain

In order to build the terrain of our game world we will use Unity's Terrain Toolbox. Terrain refers to the landscape of our game - be it desert, valley or forest.

Terrain toolbox

We will create a cartoon grass landscape for our game along wityh some rolling hills using Unity's terrain tools.

Create grass and hills

Let's create a pathway for our character to walk on.

Create a pathway

We're going to create a small pond. There are free and paid-for water assets available with which you can build simple or complex bodies of water, but for now we will just make a very simple pond.

Create a small pond

In this lesson we will add objects such as a garden, house and foresat to our game world. I've tried to keep things simple here so we'll only include objects which we will need later on, like a watering can.

Add objects to the terrain

Light in Unity is a game component which is responsible for illuminating objects. We will go over the different types of lights we can use in our game such as: spotlight, directional light, point and area light.

Lighting in Unity (spotlight, directional light, point and area light)

Learn how to add more objects to your game world by importing assets from the Unity store.

Unity asset store overview

In this module we will be covering the basics of scripting in Unity with C#. If you haven't done any programming before, don't worry - we will cover the core concepts. Additionally, whenever we write a C# script for our game, I will explain the lines of code.

Introduction to scripting in Unity

A variable is a reference to some value in memory. Think of it as a container for holding a value. Before a value can be stored, its type must be specified (by default C# is a strongly typed language).

Variables

We will discuss the data types that will be used in our scripts. First let's understand what we mean by data types. A data type can be defined literally as a *type of value or values*. For example, your age is an integer, and your first name is a type of data composed of a sequence of characters.

Data types

Operators are used to carry out operations on operands. Operands are values or variables on which an operation is carried out.

Operators

Comments help to document your code and inform the intent of your code.

Comments

Arrays are a collection of values of the same data type. They are extremely useful data structures and help us write more complex code.

Arrays

Imagine if your code could do different things based on different conditions. Well, it can! Using conditional statements we can control the flow of our programs.

Conditional statements

You can execute a statement or block of code multiple times using loops. This is called iteration.

Loops

A function groups together code statements to perform a specific task. Whenever a function is called, all the code statements inside that function will execute.

Functions

C# is an  Object-Oriented Programming language in which the programmer can develop software in modules. This is accomplished through treating data as **objects**. A class is like a blueprint or template of a specific object in which its properties, fields, events and methods are specified.

Classes

Understanding vectors is useful before we start making games. A vector is basically a quantity which has a direction. Vectors are useful and are used a lot in Unity. They're used to store the x, y and z values of components such as transform, rotation and scale. We cannot store these values together in a general variable. We need to use vectors for that.

Vectors

The transform component is attached to every object in Unity. The transform components hold the x, y and z values for the position, rotation and scale properties of an object in respect to the game world co-ordinate system, or the parent object of child components.

Transform class and component in Unity

C# basics

In this module we'll be learning about a few fundamental concepts such as Rigidbody and colliders, which will assist us in making our character move. We'll also learn how to add animations to our character.

Third person movement

You might hear the word "physics" thrown around a lot in game development, so let's go over what physics means in Unity. In the real world, objects are affected by gravity, friction, collisions, weight etc. Likewise in a game, objects are also affected by the forces of physics.

Unity physics system

Colliders are invisible shapes on 3D objects that handle collisions. A collider can be added to a GameObject as a component, just like the Rigidbody component.

Colliders in Unity3D

We will be using Rigidbody-based movement for our character to make it move left, right, forward and backward. There are two general ways to implement movement of a character in combination with Unity's physics engine.

Third-person movement - part 2

Let's take a look at the components and properties of the camera object in the inspector window.

Third-person camera controller - part 1

Let's write a script for your camera which will follow our main character as it walks. The camera will also be able to zoom in and zoom out.

Third-person camera controller - part 2

In this module, we will be creating a system for a NPC (non-player character) to work around the game world intelligently using Unity's navigation system.

NPC patrol

Using Unity's built-in navigation system you can create NPCs (non -player characters) that will move around your game world intelligently. That is to say that the navigation system gives characters the ability to navigate your gameworld and avoid obstacles.

Navigation in Unity

In this lesson we will learn how to create a NavMesh

Create a navigation environment with NavMesh

Let's add an idle animation to our Mousey charactert to make it look more animated!

Set up the Mousey animator

In this script the Mousey NPC will patrol with animations along a certain pre-determined patrol path. The Mousey NPC will stop walking if the player crosses its path.

AI Script

PatrolPathScript script allows for the visualization of the patrol path by drawing the lines and the spheres. It also has two functions that allows the AI script to grab the current and next point in the patrol.

Patrol Path Script

A short lesson on setting up the Mousey character in the inspector window.

Set up Mousey in the inspector window

Great! Now we have our Mousey NPC that strolls back and forth as long as the main character is outside the defined circle.

Conclusion

Welcome to a course on game development for beginners! This course assumes no prior knowledge of game development. We will be learning the basics of Unity, which is a popular game engine used to make games. We will be building a social simulation game in Unity3D similar to Animal Crossing starting right from the basics. By the end of this course you will have a good grasp on the Unity editor and you will develop basic game mechanics such as third person character and camera movement and creating a navigation system for agents to patrol in your game.

Welcome to a course on game development for beginners! This course is for those who are looking for an updated,comprehensive and foundational course on the [Unity](https://unity.com/) game engine.

Unity for Beginners - Animal Crossing

Getting started with the Unity game engine

 sub-folder in the main Assets folder and make a new C# script by right-clicking then 

In this script the Mousey NPC will patrol with animations along a certain pre-determined patrol path. The Mousey NPC will stop walking if the player crosses its path. 

Non-player character (NPC): It is a character in the game that is not controlled by the player/user. It is automatically controlled by the CPU of the system. In our game, it's the character that is patrolling the scene and looking for our player.

Gizmo: It is a sphere in the game that is used to define a certain region. In our game, we define a circular region around our patrolling NPC. This is the red zone and the NPC starts chasing the player wherever the player enters this spherical zone.

Characters:
NPC mouse- The CPU controlled character that is patrolling the scene. In our case it is a mouse patrolling the scene.
Player - The character controlled by the user. In our case it is a human controlled by us.

An AI(Artificial intelligence) controlled NPC is patrolling the scene. It is moving on a fixed predefined patrolling path. Whenever our player is at a certain distance (enters the gizmo region) from the NPC, the NPC stops patrolling.
The mouse is in the still position till our player is in the spherical gizmo region. Once our player exits that region and is at a safe distance from the NPC, the NPC starts patrolling again.  

---
title:  AI Script
description: In this script the Mousey NPC will patrol with animations along a certain pre-determined patrol path. The Mousey NPC will stop walking if the player crosses its path. 
isPublicLesson: true
---

## AI Script

In the _project window_, navigate to the `Scripts` sub-folder in the main Assets folder and make a new C# script by right-clicking then `Create > C# Script` and name it `AIScript`.

In this script the Mousey NPC will patrol with animations along a certain pre-determined patrol path. The Mousey NPC will stop walking if the player crosses its path. 

**Important Definitions:**

Non-player character (NPC): It is a character in the game that is not controlled by the player/user. It is automatically controlled by the CPU of the system. In our game, it's the character that is patrolling the scene and looking for our player.

Gizmo: It is a sphere in the game that is used to define a certain region. In our game, we define a circular region around our patrolling NPC. This is the red zone and the NPC starts chasing the player wherever the player enters this spherical zone.

Characters:
NPC mouse- The CPU controlled character that is patrolling the scene. In our case it is a mouse patrolling the scene.
Player - The character controlled by the user. In our case it is a human controlled by us.

**Basic Theme of the Scene:**

An AI(Artificial intelligence) controlled NPC is patrolling the scene. It is moving on a fixed predefined patrolling path. Whenever our player is at a certain distance (enters the gizmo region) from the NPC, the NPC stops patrolling.
The mouse is in the still position till our player is in the spherical gizmo region. Once our player exits that region and is at a safe distance from the NPC, the NPC starts patrolling again.  

NPC States:
Patrolling

Game Begins:

The initial state of the NPC is the patrolling state. We can change it manually according to our needs. First of all the patrolling path is checked. If no patrol path is assigned then a warning message to add the path is shown. 
Initially, we assign the player to a variable, get its position coordinates. We also assign a navigation mesh to the NPC. 

Checking on every frame of the game:
A gizmo is developed around the computer character (NPC). When the player enters this spherical gizmo then the NPC stops patrolling and stands still. The size of the gizmo is allocated by the user. This means we can assign the distance after which the NPC would start looking for our player. The center of the gizmo sphere is on the NPC.

The CPU keeps track of the position of the player all the time. Based on the position of the player and the variables, the NPC can be in the following states at any given time.

State 1 - Patrolling : 
The NPC moves on a fixed patrol path. It stops at each patrol point for 3 seconds (can be changed). After that, it continues to patrol. While traveling the NPC takes into account the current and the next patrol point. It tries to move from one patrol point to another. The NPC has a walking animation while patrolling.

We find the distance between the player and the NPC. The following states are possible after that: 
If the Player is in a spherical gizmo (distance is less than the safe distance between player and NPC): 
In the current implementation the NPC mouse would stop patrolling and stand still at its position. It would stand still till the player leaves the gizmo

If the variable values are such that both the attack and the chase triggers are off, then the NPC would just talk to the player. It would just stop walking.
If the attack trigger is true then the NPC would start chasing the player. Because the NPC needs to catch (come close) to the player before attacking it.
If the chase trigger is true then the NPC would start chasing the player. 
If none of the above cases are met then the NPC just continues its patrolling. But in the given code, this situation never arises. NPC tends to chase, talk or attack once the player enters the red zone.

If the player is not in the spherical gizmo then the NPC just keeps on moving on the patrol path.

The NPC checks whether it is on the patrol point or not.  If it is on the patrol point then it stays there for some time (3sec in our case). After that, we set our destination to the next patrol point and move towards it.

Extra Information:
The player is given a PLAYER tag in unity so that it can be accessed easily.

Now open your `AIScript` in Visual Studio and copy and paste the following:

_Note_ each line is commented for your understanding.

[comment]: <GM: I think you need to explain a bit more about this before the script. What is this script for? What does it do (at a high level)? Why is it called AI? You have a bit at the end of 6.6 which could be moved to the top here (and the next page) and expanded.>

[comment]: <GM: then give an overview of the steps in the code, maybe including an explanation of any terminology such as lerp? >

[comment]: <GM: not sure what the notes at the bottom are for? >

[comment]: <GM: then let me have it back to read through >

    //Make sure to add the navmesh agent to the AI. 
    //Add a tag to the player. 
    using System;
    using System.Collections;
    using System.Collections.Generic;
    using UnityEngine;
    using UnityEngine.AI;

    enum AIState //Various states that the AI will be in. 
    {
        Patrol,
        StopToTalk,
        Chase,
        Attack
    }
    public class AILogic : MonoBehaviour
    {
       

        [Header("AI States")]
        [SerializeField] private AIState currentState = AIState.Patrol; //Default state can be set in the inspector as well. 


        [Header("AI Movements")]

        [SerializeField] private Transform playerPosition; // player's Transform object that is used to keep track of AI's destination
        [SerializeField] private float stoppingApproachDistance = 2f; // when we get this close, stop moving


        [SerializeField] private float LookAtSpeed = 2f; // speed at which we rotate towards our destination



        [Header("Patrol Path Controls")]

        [SerializeField] PatrolPath patrolPath; // reference to PatrolPath object
        [SerializeField] private float PatrolPointTolerance = 1.5f; //how far the AI has to be from the patrol point before stopping 
        [SerializeField] private float patrolPointWaitTime = 3f; // how many seconds to stand at each patrol point

        private int currentPatrolPointIndex = 0; // index of current patrol point, starting with 0
        private Vector3 nextPosition; // location of current patrol point

        [Header("Interaction with Player")]
        [SerializeField] private float AggroRadius = 5f; //the radius of the sphere that the computer player will have. If you go in this zone the NPC will search for you. 
        [SerializeField] private bool FollowPlayerInRange = false; // should the AI keep chasing the player at a distance? ('stoppingApproachDistance' is the distance)
        [SerializeField] private GameObject player; // reference to player's GameObject
        [SerializeField] private bool AttackPlayer = false;//no code for this trigger but depending on what you do in the future this will be available. 