Function Basics

What is a Function?

A function is a block of code that performs a specific task. Instead of repeating the same code multiple times, you can create a function and reuse it. In Unity, you can create functions for player attacks, enemy defeats, item collection, etc.

Creating a Function

public class Player : MonoBehaviour
{
    void AttackEnemy()
    {
        Debug.Log("Attacking enemy!");
        DealDamage(10);
        PlayAttackSound();
        UpdateCombatUI();
    }
    
    void DealDamage(int damage) { }
    void PlayAttackSound() { }
    void UpdateCombatUI() { }
}

• Components
  • void: means this function doesn't return a value (only performs actions)
  • AttackEnemy: function name (use clear names that describe the action)
  • { }: contains the code to execute

Calling a Function

public class Player : MonoBehaviour
{
    void Update()
    {
        // Attack when left mouse button is pressed
        if (Input.GetMouseButtonDown(0))
        {
            AttackEnemy();  // Execute function
        }
        
        // Jump when spacebar is pressed
        if (Input.GetKeyDown(KeyCode.Space))
        {
            Jump();  // Execute different function
        }
    }
    
    void AttackEnemy()
    {
        Debug.Log("Attacking enemy!");
        // Attack logic...
    }
    
    void Jump()
    {
        Debug.Log("Jump!");
        // Jump logic...
    }
}

• Advantages
  • No need to write the same code multiple times (reuse attack logic in multiple places)
  • Modify in one place when needed (change attack method by modifying one function)
  • Code is clean and easy to read (AttackEnemy() clearly shows what it does)
  • Easy to fix bugs (fix in one place applies everywhere)

Why Use Functions?

Without functions (inefficient):

void Update()
{
    if (Input.GetMouseButtonDown(0))
    {
        // Repeat attack logic every time
        Debug.Log("Attacking enemy!");
        DealDamage(10);
        PlayAttackSound();
        UpdateCombatUI();
        
        // Write the same code again in another place
        Debug.Log("Attacking enemy!");
        DealDamage(10);
        PlayAttackSound();
        UpdateCombatUI();
    }
}

With functions (efficient):

void Update()
{
    if (Input.GetMouseButtonDown(0))
    {
        AttackEnemy();  // Simply call function
    }
    
    if (Input.GetKeyDown(KeyCode.Q))
    {
        AttackEnemy();  // Reuse same function
    }
}

void AttackEnemy()
{
    Debug.Log("Attacking enemy!");
    DealDamage(10);
    PlayAttackSound();
    UpdateCombatUI();
}

Actual benefits in game development:

• When changing attack logic, modify only the AttackEnemy() function and it applies everywhere
• Code is easier to read so other developers can understand it easily
• Easy to fix bugs (fix in one place solves it everywhere)
• Easy to test (test just one function)

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