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

So i get a null reference exception whenever i run the game but can't figure out what's throwing it.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class TP_Camera : MonoBehaviour
5. {
6.     public static TP_Camera Instance;
7.  
8.     public Transform TargetLookAt;
9.     public float Distance = 5;
10.     public float DistanceMin = 3;
11.     public float DistanceMax = 10;
12.     public float DistanceSmooth = 0.05f;
13.     public float X_MouseSensitivity = 5;
14.     public float Y_MouseSensitivity = 5;
15.     public float MouseWheelSensitivity = 5;
16.     public float X_Smooth = 0.05f;
17.     public float Y_Smooth = 0.1f;
18.     public float Y_MinLimit = -40;
19.     public float Y_MaxLimit = 80;
20.  
21.  
22.     private float mouseX = 0;
23.     private float mouseY = 0;
24.     private float velX = 0;
25.     private float velY = 0;
26.     private float velZ = 0;
27.     private float velDistance = 0;
28.     private float startDistance = 0;
29.     private float desiredDistance = 0;
30.     private Vector3 desiredPosition = Vector3.zero;
31.     private Vector3 position = Vector3.zero;
32.  
33.  
34.     void Awake()
35.     {
36.         Instance = this;
37.     }
38.  
39.     // Use this for initialization
40.     void Start ()
41.     {
42.         Distance = Mathf.Clamp (Distance, DistanceMin, DistanceMax);
43.         startDistance = Distance;
44.         Reset ();
45.     }
46.    
47.     // Update is called once per frame
48.     void LateUpdate ()
49.     {
50.         if (TargetLookAt = null)
51.             return;
52.  
53.         HandlePlayerInput ();
54.  
55.         CalculateDesiredPosition ();
56.  
57.         UpdatePosition ();
58.     }
59.  
60.     void HandlePlayerInput()
61.     {
62.         var deadZone = 0.01;
63.  
64.         if (Input.GetMouseButton (1))
65.             mouseX += Input.GetAxis ("Mouse X") * X_MouseSensitivity;
66.             mouseY -= Input.GetAxis ("Mouse Y") * Y_MouseSensitivity;
67.  
68.         mouseY = Helper.ClampAngle (mouseY, Y_MinLimit, Y_MaxLimit);
69.  
70.         if (Input.GetAxis ("Mouse ScrollWheel") < -deadZone || Input.GetAxis ("Mouse ScrollWheel") > deadZone)
71.             desiredDistance = Mathf.Clamp (Distance - Input.GetAxis ("Mouse Scroll Wheel") * MouseWheelSensitivity, DistanceMin, DistanceMax);
72.     }
73.  
74.     void CalculateDesiredPosition()
75.     {
76.         Distance = Mathf.SmoothDamp (Distance, desiredDistance, ref velDistance, DistanceSmooth);
77.  
78.         desiredPosition = CalculatePosition (mouseY, mouseX, Distance);
79.     }
80.  
81.     Vector3 CalculatePosition(float rotationX, float rotationY, float distance)
82.     {
83.         Vector3 direction = new Vector3 (0, 0, -distance);
84.         Quaternion rotation = Quaternion.Euler (rotationX, rotationY, 0);
85.         return TargetLookAt.position + rotation * direction;
86.     }
87.  
88.     void UpdatePosition()
89.     {
90.         var posX = Mathf.SmoothDamp (position.x, desiredPosition.x, ref velX, X_Smooth);
91.         var posY = Mathf.SmoothDamp (position.y, desiredPosition.y, ref velY, Y_Smooth);
92.         var posZ = Mathf.SmoothDamp (position.z, desiredPosition.z, ref velZ, X_Smooth);
93.         position = new Vector3 (posX, posY, posZ);
94.  
95.         transform.position = position;
96.  
97.         transform.LookAt (TargetLookAt);
98.     }
99.  
100.     public void Reset()
101.     {
102.         mouseX = 0;
103.         mouseY = 10;
104.         Distance = startDistance;
105.         desiredDistance = Distance;
106.     }
107.  
108.     public static void UseExistingOrCreateNewMainCamera()
109.     {
110.         GameObject tempCamera;
111.         GameObject targetLookAt;
112.         TP_Camera myCamera;
113.  
114.         if (Camera.main != null)
115.             tempCamera = Camera.main.gameObject;
116.         else
117.             tempCamera = new GameObject ("Main Camera");
118.             tempCamera.AddComponent <Camera>();
119.             tempCamera.tag = "MainCamera";
120.  
121.         tempCamera.AddComponent <TP_Camera>();
122.         myCamera = tempCamera.GetComponent ("TP_Camera") as TP_Camera;
123.  
124.         targetLookAt = GameObject.Find ("targetLookAt") as GameObject;
125.  
126.         if (targetLookAt == null)
127.             targetLookAt = new GameObject ("targetLookAt");
128.             targetLookAt.transform.position = Vector3.zero;
129.  
130.         myCamera.TargetLookAt = targetLookAt.transform;
131.            
132.     }
133. }

This is the error:

NullReferenceException: Object reference not set to an instance of an object
TP_Camera.CalculatePosition (Single rotationX, Single rotationY, Single distance) (at Assets/Scripts/TP_scripts/TP_Camera.cs:85)
TP_Camera.CalculateDesiredPosition () (at Assets/Scripts/TP_scripts/TP_Camera.cs:78)
TP_Camera.LateUpdate () (at Assets/Scripts/TP_scripts/TP_Camera.cs:55)

If you're interested this is the video series I've been copying from. It's meant for a third person game.

https://www.3dbuzz.com/training/view/3rd-person-character-system

 

http://docs.unity3d.com/Manual/NullReferenceException.html

 

TargetLookAt isn't assigned at line 85.

That's because on line 50 you're saying if(TargetLookAt = null) which is setting TargetLookAt to be null

= : Set a value
== : Check if values are the same

Line 50 should be

if(TargetLookAt == null)

 

Son of a bitch, it's the little things that screw you.

 

That's how game dev works