Raycasting for a period of time

Unity Engine
1

Ive tried looking this up and i haven’t found anything helpful.

Im using raycasting and I want to know if this ray has hit an object for lets say 5 or more seconds.

Whats the best way to do this?

Thanks!

2

Coroutine.

3

How exactly, if i understood the documentation correctly it is essentially a function that resumes after each frame, how would I handle the timing issue? How do I record the initial time the ray hits the object and compare that with the current time? ( I know how to do this but how do i reset the initial time after the raycast exits the object?)

4

There are multiple ways to do this.
I created a simple RayCaster class to simplify ray casting (see below).
How to use the class:

private RayCaster ray;
private float rayHitStart = 0f;

void Start() {
    ray = new RayCaster();
    ray.OnRayEnter += Ray_OnEnter;
    ray.OnRayStay += Ray_OnStay;
    ray.OnRayExit += Ray_OnExit;
    // ray.LayerMask = RayCaster.GetLayerMask("Wall");  // OPTIONAL
    ray.StartTransform = startObject.transform;
    ray.EndTransform = endObject.transform;
}

void LateUpdate() {
    ray.CastRay();
    // ray.CastLine();  // If you want to use a Line Caster instead.
}


void Ray_OnEnter(Collider collider) {
    if (collider.name == "ObjectName") {
        rayHitStart = Time.time;
    }
}

void Ray_OnStay(Collider collider) {
    if (collider.name == "ObjectName") {
        if (Time.time - rayHitStart > 5f) {
            // Object has been hit for five seconds - do something!
        }
    }
}

void Ray_OnExit(Collider collider) {
    if (collider.name == "ObjectName") {
        rayHitStart = 0f;
    }
}

RayCaster class:

using System;
using System.Collections;
using UnityEngine;

public class RayCaster {

    public Transform StartTransform;
    public Transform EndTransform;
    public Vector3 Direction;
    public float RayLength;
    public int LayerMask = 0;

    public event Action<Collider> OnRayEnter;
    public event Action<Collider> OnRayStay;
    public event Action<Collider> OnRayExit;

    Collider previous;
    RaycastHit hit = new RaycastHit();

    public bool CastRay() {
        Physics.Raycast(StartTransform.position, Direction, out hit, RayLength, LayerMask);
        ProcessCollision(hit.collider);
        return hit.collider != null ? true : false;
    }

    public bool CastLine() {
        Physics.Linecast(StartTransform.position, EndTransform.position, out hit, LayerMask);
        ProcessCollision(hit.collider);
        return hit.collider != null ? true : false;
    }

    private void ProcessCollision(Collider current) {
        // No collision this frame.
        if (current == null) {
            // But there was an object hit last frame.
            if (previous != null) {
                DoEvent(OnRayExit, previous);
            }
        }

        // The object is the same as last frame.
        else if (previous == current) {
            DoEvent(OnRayStay, current);
        }

        // The object is different than last frame.
        else if (previous != null) {
            DoEvent(OnRayExit, previous);
            DoEvent(OnRayEnter, current);
        }

        // There was no object hit last frame.
        else {
            DoEvent(OnRayEnter, current);
        }

        // Remember this object for comparing with next frame.
        previous = current;
    }

    private void DoEvent(Action<Collider> action, Collider collider) {
        if (action != null) {
            action(collider);
        }
    }

    public static int GetLayerMask(string layerName, int existingMask=0) {
        int layer = LayerMask.NameToLayer(layerName);
        return existingMask | (1 << layer);
    }

}

[Edit] Various bug fixes and typos.
The above code hasn’t been tested (except the RayCaster class).
I just whipped it up for a quick example, but should work.