Transform Variable gives "Object Reference" error

Unity Engine
1

I am making an FPS game and I am still in VERY early stages. The way I have shooting is with Raycasts and there is another way I can make Raycast shooting, but if I do it a different way, it would be a little hard to emulate bullet tracers and if the gun would be through a wall, then the player could still shoot and kill something which is bad. I am going to copy and paste my whole script. The error is on line 142. I do not know why it is giving me this error because I don’t know what to reference. One more thing, this is what the error says EXACTLY:

"NullReferenceException: Object reference not set to an instance of an object
WeaponsSystem.AssignTransform () (at Assets/Scripts/Player Scripts/Combat Scripts/WeaponsSystem.cs:142)
WeaponsSystem.Update () (at Assets/Scripts/Player Scripts/Combat Scripts/WeaponsSystem.cs:35)"

Please help me!

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class WeaponsSystem : MonoBehaviour
{
    //Class References
    public EconomySystem economySystem;
    public WeaponType weaponType = new WeaponType (0.0f, 0.0f, 0, 0.0f, 0.0f, "", "", "");

    //Shooting Variables
    public Transform bloodDecal;

    private float nextFire = 0.0f;

    void Start ()
    {
        //{TEMP} This assigns Combat Knife as weapon player is using. This is {TEMP}
        //weaponType = new WeaponType (0.3f, 10.0f, 0, 10.0f, 1.5f, "Melee", "Melee", "Combat Knife");
        weaponType = new WeaponType (0.3f, 10.0f, 30, 10.0f, 25.0f, "Fully-Automatic", "Assault Rifle", "M4A1");
        weaponType.weaponAmmoMags[0] = 10;

        print ("Fire Rate: " + weaponType.weaponFireRate + "\n" +
            "Damage: " + weaponType.weaponDamage + "\n" +
            "Accuracy: " + weaponType.weaponAccuracy + "\n" +
            "Shoot Type: " + weaponType.weaponShootType + "\n" +
            "Gun Type: " + weaponType.weaponType + "\n" +
            "Gun Name: " + weaponType.weaponName);
    }

    void Update ()
    {
        WeaponFireRate ();
        CheckAmmo ();
        AssignTransform ();
    }

    void CheckAmmo ()
    {
        if (Input.GetKeyDown (KeyCode.R))
        {
            //**Assault Rifle Ammo Check**
            if (weaponType.weaponType == "Assault Rifle" && weaponType.weaponAmmoInMag >= 0 && weaponType.weaponAmmoInMag < weaponType.weaponAmmoAllowedInMag && weaponType.weaponAmmoMags[0] >= 1)
            {
                ReloadWeapon ("Assault Rifle");
            }
        }
    }

    void ReloadWeapon (string WeaponType)
    {
        //**Assault Rifle Reloading**
        if (WeaponType == "Assault Rifle")
        {
            if (weaponType.weaponName == "M4A1")
            {
                weaponType.weaponAmmoInMag = weaponType.weaponAmmoAllowedInMag;
                weaponType.weaponAmmoMags[0]--;
                print ("Ammo in Magazine: " + weaponType.weaponAmmoInMag + "\n" +
                       "Ammo Magazine(s): " + weaponType.weaponAmmoMags[0]);
            }
        }
    }

    void WeaponFireRate ()
    {
        //Makes sure that a Melee type of weapon isn't Fully-Automatic
        if (weaponType.weaponShootType == "Melee")
        {
            if (Input.GetButtonDown ("Fire1") && Time.time > nextFire)
            {
                nextFire = Time.time + weaponType.weaponFireRate;
                FireWeapon ();
            }
        }
        //Makes sure that a Semi-Automatic, Bolt-Action, or Pump-Action type of weapon isn't Fully-Automatic
        else if (weaponType.weaponShootType == "Semi-Automatic" || weaponType.weaponShootType == "Bolt-Action" || weaponType.weaponShootType == "Pump-Action")
        {
            if (Input.GetButtonDown ("Fire1") && Time.time > nextFire && weaponType.weaponAmmoInMag >= 1)
            {
                weaponType.weaponAmmoInMag--;
                nextFire = Time.time + weaponType.weaponFireRate;
                FireWeapon ();
            }
            else if (Input.GetButtonDown ("Fire1") && Time.time > nextFire && weaponType.weaponAmmoInMag == 0)
            {
                print ("Semi-Automatic, Bolt-Action, or Pump-Action Weapon out of ammo in magazine. Reload!");
            }
        }
        //Makes sure a Fully-Automatic weapon is Fully-Automatic, not anything else
        else if (weaponType.weaponShootType == "Fully-Automatic")
        {
            if (Input.GetButton ("Fire1") && Time.time > nextFire && weaponType.weaponAmmoInMag >= 1)
            {
                weaponType.weaponAmmoInMag--;
                nextFire = Time.time + weaponType.weaponFireRate;
                FireWeapon ();
            }
            else if (Input.GetButton ("Fire1") && Time.time > nextFire && weaponType.weaponAmmoInMag == 0)
            {
                print ("Fully-Automatic Weapon out of ammo in magazine. Reload!");
            }
        }
        //Spits out an error if gun isn't Melee, Semi-Automatic, Fully-Automatic, Bolt-Action, Pump-Action
        else
        {
            Debug.LogError ("Something has gone wrong in the 'WeaponsSytem.cs' script." + "\n" +
                            "Restart the game and if this error still shows, check the 'WeaponsSystem.cs' script." + "\n" +
                            "One of the error(s) that may occur could be a spelling for the 'weaponType' variable.");
        }
    }

    void FireWeapon ()
    {
        //Raycasting Information
        //Ray ray = Camera.main.ScreenPointToRay (new Vector3(Screen.width / 2.0f, Screen.height / 2.0f, 0.0f)); {OTHER RAYCAST METHOD, DON'T WANT TO USE IF I DON'T HAVE TO}
        Ray ray = new Ray (weaponType.weaponTransform.position, weaponType.weaponTransform.forward);
        RaycastHit hitInfo = new RaycastHit ();

        //Checks to see if Raycast hits something
        if (Physics.Raycast (ray, out hitInfo, weaponType.weaponHitRange))
        {
            print ("Object Weapon just hit: " + hitInfo.collider.tag);

            if (hitInfo.collider.tag == "Common Zombie")
            {
                //Adds Blood Decal to zombie when hit
                Transform bloodDecalClone = (Transform)Instantiate (bloodDecal, hitInfo.point, Quaternion.identity);
                Destroy (bloodDecalClone.gameObject, 0.2f);
              
                //Adds 10 ZomB Cash
                economySystem.ZomBCash += 10;
              
                //Sends Messsage to the zombie
                hitInfo.collider.SendMessage ("ApplyDamageToZombie", weaponType.weaponDamage, SendMessageOptions.DontRequireReceiver);
            }
        }
    }

    void AssignTransform ()
    {
        weaponType.weaponTransform = GameObject.Find (weaponType.weaponName).transform;
        print (weaponType.weaponTransform); //FOR DEBUGGING ONLY
    }
}

public class WeaponType
{
    public float weaponFireRate = 0.0f;
    public float weaponDamage = 0.0f;
    public int[] weaponAmmoMags = new int[5];
    /*
     * weaponDamge Array Indexs
     * [0]: "Assault Rifle" Ammo Mags,
     * [1]: "Sub-Machine Gun" Ammo Mags,
     * [2]: "Handgun" Ammo Mags,
     * [3]: "Sniper Rifle" Ammo Mags,
     * [4]: "Shotgun" Ammo Mags
    */
    public int weaponAmmoInMag = 0;
    public int weaponAmmoAllowedInMag = 0;
    public float weaponAccuracy = 0.0f;
    public float weaponHitRange = 0.0f;

    public string weaponShootType;
    /*
     * TYPES OF SHOOT TYPES TO CHOOSE FROM: (8 in all)
     *
     * FOR MELEE:
     * "Melee"
     *
     * FOR ASSAULT RIFLES AND SUB-MACHINE GUNS:
     * "Fully-Automatic",
     * "Semi-Automatic"
     *
     * FOR HANDGUNS:
     * "Semi-Automatic" (ALWAYS CHOOSE THIS FOR HANDGUNS)
     *
     * FOR SNIPER RIFLES:
     * "Bolt-Action",
     * "Semi-Automatic"
     *
     * FOR SHOTGUNS:
     * "Pump-Action",
     * "Semi-Automatic",
     * "Fully-Automatic"
    */
    public string weaponType;
    /*
     * TYPES OF GUNS TO CHOOSE FROM:
     *
     * "Melee"
     * "Assault Rifle",
     * "Sub-Machine Gun",
     * "Handgun",
     * "Sniper Rifle",
     * "Shotgun"
    */
    public string weaponName;

    public Transform weaponTransform;

    public WeaponType (float FireRate, float Damage, int AmmoAllowedInMag, float Accuracy, float HitRange, string ShootType, string WeaponType, string Name)
    {
        weaponFireRate = FireRate;
        weaponDamage = Damage;
        weaponAmmoAllowedInMag = AmmoAllowedInMag;
        weaponAccuracy = Accuracy;
        weaponHitRange = HitRange;
        weaponShootType = ShootType;
        weaponType = WeaponType;
        weaponName = Name;
    }
}
2

Does a gameobject with the name ‘M4A1’ exist in your scene when this script is being executed?

3

^^ I’d bet on that, as well. Also, is there a reason you need to assign the transform every frame? Even if you fix your null reference, running a Gameobject.Find() every update should generally be avoided. It can get to be a expensive.

4

True.

Also, enums may be helpful for you, too. I’d prefer them instead of having string comparisons as conditions. Saves time, less error prone etc…
However, if you want to stick to strings, define them once i.e. as ‘const static string’ and use those variables instead. Less errors due to typos at least and way easier to maintain than all these literals.

5

Yes, just the object is disabled. If it needs to be enabled, that might be why. I will try that in a second.

You have a point there that I never thought of. It is just that like when the player switches weapons, like say to the ‘Combat Knife’, then the transform has to be the Combat Knife’s transform. But I think I could change that by assigning the transform with a method that isn’t run in Update() ALL the time. Like maybe SwitchWeapons() and that is when it changes or something similar.

I was going to use enums because I have used them before and they work pretty well. I just wanted to try this way of doing things because I have never really tried this before, although I do agree that using strings for comparisons can go wrong.

Would it be better to make the public variables at the op of the script in the first class instead of in the second class? I will try this along with the different GameObject method. Thank you all for trying to help me out!

EDIT:
I fixed the reference error by having the GameObject enabled. (Duh!) I will not do GameObject.Find every frame any more though, thanks @Zaladur