🧱 Classes and Objects – Building Blocks of Game Logic

• Welcome to the land of OOP – Object-Oriented Programming.
• Don’t run. It sounds fancy, but it’s actually what you’ve already been doing this whole time.

• In Unity, every script is a class. Every object in your scene is (you guessed it) an object.
• Let’s break it down and make sense of it all.

🧠 What is a Class?

• A class is a blueprint.
• It describes what something is, and what it can do.

Example:

1public class Enemy2{3    public int health = 100;4 5    public void TakeDamage(int amount)6    {7        health -= amount;8    }9}

• This is a blueprint for an Enemy.
• It says: “I have health. I can take damage.”

But on its own, it doesn’t exist in the game yet.

👤 What is an Object?

An object is a real, living version of that blueprint.

In Unity, when you attach a script to a GameObject, Unity creates an instance (object) of that class.

You can also create multiple objects from the same class:

1Enemy goblin = new Enemy();2Enemy troll = new Enemy();3 4goblin.TakeDamage(20);5troll.TakeDamage(50);

Now we have two enemies - each with their own health.

🧰 Unity + MonoBehaviour = Magic

In Unity, your scripts usually extend (inherit from) MonoBehaviour:

1public class Player : MonoBehaviour2{3    public int health = 100;4 5    void Start()6    {7        Debug.Log("Player spawned!");8    }9}

MonoBehaviour gives you access to Unity-specific magic like:

• Start(), Update(), OnCollisionEnter()
• Inspector visibility for public fields
• Component access via GetComponent<>()

Basically, it plugs your code into the Unity engine.

🧪 Example: Player + Enemy System

Let’s say you want each enemy to have its own health and logic:

1public class Enemy : MonoBehaviour2{3    public string enemyName;4    public int health;5 6    public void TakeDamage(int amount)7    {8        health -= amount;9        Debug.Log(enemyName + " took " + amount + " damage!");10    }11}

Now you can:

• Add this script to any enemy GameObject
• Customize their health and name in the Inspector
• Call TakeDamage() from another script when needed

🎉 Boom - reusable, scalable logic!

🤓 Why Use Classes?

• ✅ Reuse logic across objects (DRY = Don't Repeat Yourself)
• ✅ Keep code modular and organized
• ✅ Create cleaner, more maintainable games
• ✅ Add powerful structure to bigger projects

Even the Unity components like Rigidbody2D, Camera, and Transform… are all classes!

🧪 Mini Challenge: Create an Enemy Army

1. Create a script Enemy.cs with: public string enemyName
2. public int health
3. public void TakeHit(int damage) that logs a message
4. Create 3 GameObjects in the scene with different names and health
5. Call TakeHit() from another script to damage each one

Optional: Make enemies explode into a dramatic Debug.Log.

🚀 What’s Next?

Now that you know how to write reusable scripts and build structured logic, it’s time to learn how Unity handles code in motion - with its unique built-in methods like Start() and Update().

⚙️ Go to Lesson 12 → Unity-Specific Scripting (MonoBehaviour, Start, Update)