Resolved How to find specific colliders using RaycastHit?

I'm trying to make the AI for my horror game chase the player, but a NullRef keeps popping up in the logs telling me that an object isn't set to a reference - the 'object' in this case being the FoundPlayer hitInfo in a raycast. Can anyone help figure out how to find whether a specific collider has been hit?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.AI;
5.  
6. public class EnemyScript : MonoBehaviour
7. {
8.     public enum _State
9.     {
10.         Roaming,
11.         Stalking,
12.         Chasing
13.     }
14.     public _State State;
15.  
16.     public Transform[] RoomsToVisit;
17.  
18.     public MeshCollider ViewCone;
19.     public GameObject Target;
20.     public CapsuleCollider TargetBody;
21.     public NavMeshAgent Enemy;
22.     public Transform Destination;
23.     public Transform LooksAtPlayer;
24.     public float WalkingSpeed = 3f;
25.     public float RunningSpeed = 14f;
26.  
27.     // Start is called before the first frame update
28.     void Start()
29.     {
30.         ViewCone.GetComponent<MeshRenderer>().enabled = false;
31.         TargetBody = Target.GetComponent<CapsuleCollider>();
32.     }
33.  
34.     // Update is called once per frame
35.     void Update()
36.     {
37.         if (ViewConeScript.TouchingPlayer)
38.         {
39.             PlayerIsInView();
40.         }
41.         bool SamePosX = Mathf.Approximately(Enemy.transform.position.x, Destination.transform.position.x);
42.         bool SamePosY = Mathf.Approximately(Enemy.transform.position.y, Destination.transform.position.y);
43.         bool SamePosZ = Mathf.Approximately(Enemy.transform.position.z, Destination.transform.position.z);
44.         switch (State)
45.         {
46.             case _State.Roaming:
47.                 if (SamePosX && SamePosY && SamePosZ)
48.                 {
49.                     int RandomNumber = Mathf.RoundToInt(Random.Range(0, RoomsToVisit.Length - 1));
50.                     Destination.SetPositionAndRotation(RoomsToVisit[RandomNumber].position, RoomsToVisit[RandomNumber].rotation);
51.                 }
52.                 Enemy.SetDestination(Destination.position);
53.                 Enemy.speed = WalkingSpeed;
54.                 Enemy.acceleration = 1000f;
55.                 break;
56.             case _State.Stalking:
57.                 Enemy.SetDestination(Destination.position);
58.                 Enemy.speed = WalkingSpeed;
59.                 Enemy.acceleration = 1000f;
60.                 break;
61.             case _State.Chasing:
62.                 Enemy.SetDestination(Destination.position);
63.                 Enemy.speed = RunningSpeed;
64.                 Enemy.acceleration = 18f;
65.                 //Enemy.transform.LookAt(Target.transform);
66.                 if (SamePosX && SamePosY && SamePosZ)
67.                 {
68.                     State = _State.Roaming; //Set to Stalking and have enemy search rooms for player
69.                 }
70.                 break;
71.             default:
72.                 break;
73.         }
74.     }
75.  
76.     void PlayerIsInView()
77.     {
78.         LooksAtPlayer.LookAt(Target.transform);
79.         float DistFromTarget = Vector3.Distance(Target.transform.position, Enemy.transform.position);
80.         LayerMask mask = LayerMask.GetMask("Player Layer");
81.         RaycastHit FoundPlayer;
82.         Physics.Raycast(origin: Enemy.transform.position, direction: LooksAtPlayer.rotation.eulerAngles, hitInfo: out FoundPlayer, maxDistance: 160f, layerMask: mask);
83.         if (FoundPlayer.collider.transform.position == TargetBody.transform.position) //This is the problem child in question
84.         {
85.             State = _State.Chasing;
86.             Destination.SetPositionAndRotation(Target.transform.position, Target.transform.rotation);
87.             Debug.Log("Player is in sight");
88.         }
89.         else
90.         {
91.             Debug.Log("There is no player in sight");
92.         }
93.     }
94. }

 

Physics.Raycast will return true if it has hit something, so use it with if to wrap up the raycast hit logic, then you won't try to process null hitInfo:

e.g.

Code (CSharp):

1. if(Physics.Raycast(origin: Enemy.transform.position, direction: LooksAtPlayer.rotation.eulerAngles, hitInfo: out FoundPlayer, maxDistance: 160f, layerMask: mask))
2. {// process raycast hitInfo here}

From https://docs.unity3d.com/ScriptReference/RaycastHit.html you can see you can get lots of useful information, e.g. collider will tell you which collider you have hit.

e.g.

Code (CSharp):

1. Debug.Log("Hit: " + hitInfo.collider.name);

To debug your raycasting you will find it useful to use https://docs.unity3d.com/ScriptReference/Debug.DrawRay.html (ensure gizmos are on and watch the game in scene view - the ray is not rendered in game view). Note, apply your raycast length as a scalar to the direction in Debug.DrawRay.

I would guess that your problem is related to one of the following:
a) Your ray is not being cast from where you expect it to be cast from.
b) Your ray direction is not what you are expecting it to be.
c) Is all of the player in the Player Layer? E.g. does he have an accessory that is not in that layer.

EDIT
You can use hitinfo.point to get a position and then move a marker object (e.g. small sphere) to that point, this may help you understand where a ray is colliding with your player.

 

Thanks so much for this! Turns out the ray direction was way off because it was being fed Euler angles for rayDirection. Although I ended up using LineCast instead, your tips on using DrawRay and wrapping up the raycast logic were very insightful.

 

This might not be relevant to your question but I had some trouble finding the answer to a similar question that led me here and I figured I might be able to help other lost souls. If you have multiple colliders attached to a single object, you can get the specific

RaycastHit.collider

by casting the collider to the type that you are expecting to find. For instance, I needed a box collider so in order to get the properties for it, I had to use

raycastHit.collider as BoxCollider