Proper way to reference scripts in unity?

Questions & Answers
,
1

I’m relatively new to unity and I was wondering about the best way to reference a script in unity through code.

So far I can only call methods (and access variables) using specific reference types (GameManager, SpawnManager, PlayerScript, ect), however I cant seem to find a good way to access scripts that belong to other objects, say the enemy, or a powerup.

Is there a list of other types or is there a different process for storing this kind of information?

2

So an easy way to reference a script in Unity would be to use classes.

If your script name is PlayerMovement.cs, you would reference it as:

public PlayerMovement variableName;

You can then use the script like so:

variableName.ExamplePublicMethod();
7

Let’s say you have a simple PlayerComponent, like this:

PlayerComponent.cs 
using UnityEngine;

public class PlayerComponent : MonoBehaviour
{
    public int health = 100;
}

You, for example, can create a different script that will reference instance of PlayerComponent and change value of it’s health field on Start. This is the most basic way of referencing other components:

HurtPlayerOnStart.cs 
using UnityEngine;

public class HurtPlayerOnStart : MonoBehaviour
{
    [SerializeField] PlayerComponent _player;
    void Start ()
    {
        if( _player!=null )
        {
            _player.health -= 10;
        }
        else Debug.LogWarning( "player component is null! Assign this field in the Inspector window" );
    }
}

There are other ways of course. Like, you can use OnTriggerEnter to look for PlayerComponent components on colliders entering a trigger (special type of collider)

HurtZone.cs 
using UnityEngine;

[RequireComponent(typeof(BoxCollider))]
public class HurtZone : MonoBehaviour
{
    void Start ()
    {
        var collider = GetComponent<Collider>();
        if( collider.isTrigger==false )
        {
            Debug.LogWarning( "this Collider must be a trigger for this script to work. Enable `Is Trigger` now!" , this );
        }
    }
    void OnTriggerEnter ( Collider other )
    {
        var playerComp = other.GetComponent<PlayerComponent>();
        if( playerComp!=null )
        {
            playerComp.health -= 10;
            Debug.Log( "player damaged!" , this );
        }
        else Debug.Log( $"'{other.name}' has no {nameof(PlayerComponent)} so I will ignore it" , other );
    }
}

→ Unity - Scripting API: Collider.OnTriggerEnter(Collider)

→ Unity - Manual: Introduction to collision


You can also “look” for colliders in specific direction and check for specific component instances with a Raycast operation.

HurtRay.cs 
using UnityEngine;

public class HurtRay : MonoBehaviour
{
    void FixedUpdate ()
    {
        const float rayLength = 10f;
        Ray ray = new Ray( transform.position , transform.forward );
        if( Physics.Raycast( ray , out RaycastHit hit , rayLength ) )
        {
            // hit
            Debug.DrawLine( ray.origin , ray.origin + hit.point , Color.red , Time.fixedDeltaTime );

            var playerComp = hit.collider.GetComponent<PlayerComponent>();
            if( playerComp!=null )
            {
                playerComp.health -= 1;
                Debug.Log( "player damaged!" , this );
            }
            else Debug.Log( $"'{hit.collider.name}' has no {nameof(PlayerComponent)} so I will ignore it" , hit.collider );
        }
        else
        {
            // miss
            Debug.DrawLine( ray.origin , ray.origin + ray.direction * rayLength , Color.yellow , Time.fixedDeltaTime );
        }
    }
}

→ Unity - Scripting API: Physics.Raycast


Summary

This is how you can detect enemies or powerups - with triggers, collisions or raycasts basically.
Hope that helps and clears some confusion around this topic.