Follow cursor script crash

Hi
I was looking for a script to make an object follow the cursor
And very time I look for a script to make a object follow the cursor, I always find something like this:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class MouseMove2D : MonoBehaviour
6. {
7.     private Vector3 mousePosition;
8.     public float moveSpeed = 0.1f;
9.  
10.     void Update()
11.     {
12.         if (Input.GetButtonDown("Fire1"))
13.         {
14.             mousePosition = Input.mousePosition;
15.             mousePosition = Camera.main.ScreenToWorldPoint(mousePosition);
16.             transform.position = Vector2.Lerp(transform.position, mousePosition, moveSpeed);
17.         }
18.  
19.     }
20. }

But whenever I use the script, the game crashes and it gives me this error:

NullReferenceException: Object reference not set to an instance of an object
MouseMove2D.Update () (at Assets/Scripts/MouseMove2D.cs:15)​

Any help is appreciated

 

Does a main camera exist in the scene?

Camera.main

is a shorthand for

GameObject.FindWithTag("Main Camera");

.
Ensure you have a Camera attached to a GameObject with the tag "Main Camera" in your scene.

Also, because

Camera.main

is a

FindWithTag()

call, you don't want to be calling it every frame. Cache the reference instead:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. public class MouseMove2D : MonoBehaviour
5. {
6.     private Vector3 mousePosition;
7.     public float moveSpeed = 0.1f;
8.  
9.     private Camera mainCamera;
10.  
11.     void Start()
12.     {
13.         mainCamera = Camera.main;
14.     }
15.  
16.     void Update()
17.     {
18.         if (Input.GetButtonDown("Fire1"))
19.         {
20.             mousePosition = Input.mousePosition;
21.             mousePosition = mainCamera.ScreenToWorldPoint(mousePosition);
22.             transform.position = Vector2.Lerp(transform.position, mousePosition, moveSpeed);
23.         }
24.     }
25. }

 

Ok.
Thanks for your tip.
Managed to solve the issue.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class MouseMove2D : MonoBehaviour
6. {
7.     private Vector3 mousePosition;
8.     public float moveSpeed = 0.1f;
9.  
10.     public Camera mainCamera;
11.  
12.     void Update()
13.     {
14.         mousePosition = Input.mousePosition;
15.         mousePosition = mainCamera.ScreenToWorldPoint(mousePosition);
16.         transform.position = Vector2.Lerp(transform.position, mousePosition, moveSpeed);
17.     }
18. }

Thanks again!!