Press f to interact with NPCs or objects

Question

How do I change the method used for initiating the interaction. Instead of clicking object, check if within a certain radius of an object when you hit a key on your keyboard.

If within 1 unit, the player gets a message that they can press f to interact. When f is pressd, get the object they're close to and handle the interaction the same way.

PS. I'm using box collider.

Here are the script that I found. I tried this but once I start the game and press F key, its working. But I want the player to press the F key once the character is inside the collider of an object.

WorldInteraction

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

public class WorldInteraction : MonoBehaviour {
    NavMeshAgent playerAgent;

void Start() {
    playerAgent = GetComponent<NavMeshAgent>();
}

void Update() {
    if (Input.GetMouseButtonDown(0) && !UnityEngine.EventSystems.EventSystem.current.IsPointerOverGameObject()) {
        GetInteraction();
    }
}

void GetInteraction() {
    Ray interactionRay = Camera.main.ScreenPointToRay (Input.mousePosition);
    RaycastHit interactionInfo;
    if(Physics.Raycast(interactionRay, out interactionInfo, Mathf.Infinity)) {
        GameObject interactedObject = interactionInfo.collider.gameObject;
        if (interactedObject.tag == "Interactable Object") {
            interactedObject.GetComponent<Interactable>().MoveToInteraction(playerAgent);
        } else {
            playerAgent.destination = interactionInfo.point;
        }
    }
}

}

Interactable

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

public class Interactable : MonoBehaviour {
    public NavMeshAgent playerAgent;

public virtual void MoveToInteraction(NavMeshAgent playerAgent) {
    this.playerAgent = playerAgent;
    playerAgent.destination = this.transform.position;

    Interact();
}

public virtual void Interact() {
    Debug.Log ("Interacting with base class.");
}

}

NPC

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class NPC : Interactable {

public override void Interact() {
    Debug.Log ("Interacting with NPC.");
}

}

Answer 1

You could use a boxcollider set as trigger, then do something like the below in your trigger enter and exit functions. No raytracing necessary, i.e. it works when you're not looking directly at the interacted object etc.

private GameObject interactedObject;

void OnTriggerEnter(Collider c){
    interactedObject = c.gameObject;

}
void OnTriggerExit(){
    interactedObject = null;

}

then you can use if(interactedObject!=null){....} wherever you want to do something different if you're interacting.

e.g.

void Update() {
    if (Input.GetKey(KeyCode.F) && interactedObject != null) {
        GetInteraction();
    }
}

Answer 2

The script uses a raycast hit to detect whether the interactible object is visible or not.

If you want to limit the interaction range, you can check interactionInfo.distance after Physics.Raycast. This allows you to verify whether the object is close enough to interact with or not. Or you can limit the range of the raycast in the first place by replacing Mathf.Infinity with your desired maximum interaction range.