NullReferenceException: Object reference not set to an instance of an object

Hi,

First time posting here. I have seen this error in multiple threads, but still haven't found a solution to my problem, and I didnt want to hijack other threads, so:

Doing a top down game where you will walk with WASD and aim/look with mouse, was working but now I'm getting:

NullReferenceException: Object reference not set to an instance of an object
PlayerController.ControlMouse () (at Assets/Scripts/PlayerController.cs:35)
PlayerController.Update () (at Assets/Scripts/PlayerController.cs:27)

Im checking the referenced objects on 35 and 27, still cant find it, if anyone has a clue, Id be really grateful, thanks!

Heres the script:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [RequireComponent(typeof(CharacterController))]
5. public class PlayerController : MonoBehaviour {
6.  
7.     //Handling variables
8.     public float rotationSpeed = 450; //360 så ett varv per sekund
9.     public float walkSpeed = 5;
10.     public float runSpeed = 8;
11.  
12.     //System variables
13.     private Quaternion targetRotation;
14.  
15.     //Components
16.     private CharacterController controller;
17.     private Camera cam; //För mouse-styrningen
18.  
19.     void Start() {
20.  
21.         controller = GetComponent<CharacterController>();
22.         cam = Camera.main;
23.  
24.     }
25.  
26.     void Update () {
27.         ControlMouse();
28.         //ControlWASD();
29.     }
30.  
31.     void ControlMouse() {
32.  
33.         Vector3 mousePos = Input.mousePosition;
34.         mousePos = cam.ScreenToWorldPoint(new Vector3(mousePos.x, mousePos.y, cam.transform.position.y - transform.position.y));
35.         targetRotation = Quaternion.LookRotation(mousePos - new Vector3(transform.position.x,0,transform.position.z));
36.         transform.eulerAngles = Vector3.up * Mathf.MoveTowardsAngle(transform.eulerAngles.y, targetRotation.eulerAngles.y, rotationSpeed * Time.deltaTime);
37.  
38.         Vector3 input = new Vector3(Input.GetAxisRaw("Horizontal"), 0, Input.GetAxisRaw("Vertical")); //GetAxisRaw accelererar inte, snapp speed (?)
39.         Vector3 motion = input;
40.         motion *= (Mathf.Abs(input.x) == 1 && Mathf.Abs(input.z) == 1) ? .7f : 1;
41.         motion *= (Input.GetButton("Run")) ? runSpeed : walkSpeed;
42.         motion += Vector3.up * -8; //gravity
43.  
44.         controller.Move(motion * Time.deltaTime);
45.     } }
46.  

 

cam is likely null

This could probably be easily caught with some quick debugging. I suggest setting a breakpoint, attaching the debugger and step through the code to look at the values at each point. That should help you isolate the problem. Check out https://unity3d.com/learn/tutorials/topics/scripting/monodevelops-debugger

 

Thanks mate!

There was nothing wrong with the script, but for some reason my camera dropped its tag MainCamera to Untagged. No idea how that could've happened, but anyway, its fixed, thanks a lot! And thanks for the read as well!

 

2 years later, I have suffered the same problem i lost 2 hours of my time...

 

Hey Man you solved my issue! I was stucked with Cinemachine (camera set to perspective in 2D environment) getting the right mouseposition.... I checked the tag of my camera and it was set to untagged, I set it to MainCamera and it worked.... to whom is facing my same issue: if you aren't able to get right mouse position, check Main Camera tag and pass a Vector3 to mouse position with Z values the distance of your Cinemachine Camera. Hope it can help someone!