Input.mousePosition Error

Questions & Answers
1

I’m new to Unity; currently I am taking the Walker Boys training. While using Unity 3.5 I have run in to an error I cannot figure out. I used Unity scripting references in order to formulate my code. Even thought everything I have written below compiles using Mono, unity error console is outputing a NullReferenceException error with my “Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition)”. Any assistance anyone could provide would be greatly appreciated. Below is my full script.

using UnityEngine;
using System.Collections;

public class player : MonoBehaviour {

//Player Script

//Public Varuables
public string tagName;
public float rayDistance = 0.0f;
public int playerScore = 0;
public float gameTime = 20;
public int numberOfPointsToWin = 13;

//Private Varuables

// Use this for initialization
void Start ()
{
InvokeRepeating(“CountDown”,1.0f,1.0f);
}

// Update is called once per frame
void Update () 
{
	//Allows user interaction with mouse
	if(Input.GetMouseButtonDown(0))
	{
		***Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);***
		RaycastHit hit;
		
		if(Physics.Raycast(ray,out hit, rayDistance))
		{
			print("Hope this works");
			if(hit.transform.tag == tagName)
			{
				print("Hit object");
				//Vector3 location = new Vector3(Random.Range(-3.3f,3.3f), Random.Range(-2.4f,2.4f),0);
				//hit.transform.position = location;
				GameObject clicks;
				enemyScript scriptEnemy;
				scriptEnemy = hit.transform.GetComponent<enemyScript>();
				scriptEnemy.numberOfClicks -= 1;
				
				if(scriptEnemy.numberOfClicks == 0)
				{
					playerScore += scriptEnemy.enemyPoint;
				}
			}
			else
			{
				print("This object is not an Enemy!");
			}
			
		}
	}
}

void CountDown()
{
	if(--gameTime==0)
	{
		CancelInvoke("CountDown");
		
		if(playerScore >= numberOfPointsToWin)
		{
			Application.LoadLevel("menuWin");
		}
		else
		{
			Application.LoadLevel("menuLose");
		}
	}
}
void OnGUI()
{
	GUI.Label(new Rect(10,10,100,20),"Score: "+ playerScore);
	GUI.Label(new Rect(10,25,100,35),"Time: "+ gameTime);
}

}

2

Also possible: Camera.main could be returning null, if your scene doesn’t contain any cameras tagged as “MainCamera”.

You might try this:

Debug.Log(Camera.main);
Debug.Log(Input.mousePosition);
3

I tried sticking this code(commented out the enemyScript bits) in a brand new scene/project and attached the script to an object and it doesn’t generate a null-reference exception. The above poster’s comment about the camera is likely your issue.