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[Part 15] NullReferenceException: Object reference not set to an instance of an
Home › Forums › Video Game Tutorial Series › Creating a Rogue-like Shoot-em Up in Unity › [Part 15] NullReferenceException: Object reference not set to an instance of an
- This topic has 10 replies, 2 voices, and was last updated 2 weeks, 5 days ago by Terence.
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November 18, 2024 at 6:44 pm #16395::
At
<code>protected virtual float GetSpawnAngle() //Get the direction of the projectile should face when spawning { return Mathf.Atan2(movement.lastMovedVector.y, movement.lastMovedVector.x) * Mathf.Rad2Deg; }</code>
I found the same topic and I already checked the owner by using Debug.Log($”Owner: {owner.name}”); at Weapon:Item It shows ” owner: Player ” and I already assigned the weaponPrefab as a projectile into a WeaponData. Inside the weaponPrefab, I have added Projectile.cs too. What did I miss 🧐
November 18, 2024 at 6:46 pm #16396::<code>protected virtual float GetSpawnAngle() //Get the direction of the projectile should face when spawning { return Mathf.Atan2(movement.lastMovedVector.y, movement.lastMovedVector.x) * Mathf.Rad2Deg; }</code>
November 18, 2024 at 7:24 pm #16402November 18, 2024 at 9:20 pm #16411::NullReferenceException: Object reference not set to an instance of an object. Projectile.GetSpawnAngle
November 19, 2024 at 1:47 pm #16417November 19, 2024 at 4:42 pm #16421::Here from this line. When the game starts there is no weaponPrefab spawn. I don’t know why it happens I have added the weaponPrefab in the weaponData
<code>protected virtual float GetSpawnAngle() //Get the direction the projectile should face when spawning { return Mathf.Atan2(movement.lastMovedVector.y, movement.lastMovedVector.x) * Mathf.Rad2Deg; }</code>
November 19, 2024 at 6:17 pm #16422::I have checked and added the new code.
At ProjectileWeapon.cs I add this new line into the script
<code>public override void Start() { if (movement == null) { Debug.LogWarning("Movement is not assigned or cannot be found."); } }</code>
At GetSpwanAngle() I added this debug to check player movement by using this line
<code>protected virtual float GetSpawnAngle() //Get direction the projectile should face when spawning { if (movement == null) { Debug.LogWarning("Movement is null. Cannot calculate spawn angle."); return 0f; } return Mathf.Atan2(movement.lastMovedVector.y, movement.lastMovedVector.x) * Mathf.Rad2Deg; }</code>
And yes. when I press start, it shows all the LogWarning I have added. It must be an issue with the PlayerController.cs for sure.
November 19, 2024 at 6:29 pm #16423::Here is my PlayerController.Cs I am using the NewInputSystem to control player movement. I think the problem lies in the NewInputSystem. Should I revert to using the original script?
<code>using UnityEngine; using UnityEngine.InputSystem; public class PlayerController : MonoBehaviour { public static PlayerController instance; [HideInInspector] public Vector2 moveDir; //Move Directory [HideInInspector] public Vector2 lastMovedVector; [HideInInspector] public float lastHorizontalVector; //Check last HorizontalVector [HideInInspector] public float lastVerticalVector; //Check last VerticalVector Animator anim; SpriteRenderer spriteRenderer; Rigidbody2D rb; PlayerStats playerStat; void Awake() { playerStat = GetComponent<PlayerStats>(); rb = GetComponent<Rigidbody2D>(); anim = GetComponent<Animator>(); spriteRenderer = GetComponent<SpriteRenderer>(); if (instance == null) { instance = this; } else { Debug.LogWarning("EXTRA" + this + "DELETE"); Destroy(gameObject); } lastMovedVector = new Vector2(1, 0f); //at start of game the projectile weapon will have momentum } void Update() { InputManagement(); if (moveDir.x != 0 || moveDir.y != 0) { anim.SetBool("Move", true); SpriteDirectionCheck(); } else { anim.SetBool("Move", false); } } void FixedUpdate() { rb.velocity = new Vector2(moveDir.x * playerStat.MoveSpeed, moveDir.y * playerStat.MoveSpeed); } private void InputManagement() { //moveDir = new Vector2(Input.GetAxis("Horizontal"), Input.GetAxis("Vertical")).normalized; if (moveDir.x != 0) { lastHorizontalVector = moveDir.x; lastMovedVector = new Vector2(lastHorizontalVector, 0f); } if (moveDir.y != 0) { lastVerticalVector = moveDir.y; lastMovedVector = new Vector2(0f, lastVerticalVector); } if (moveDir.x == 0 && moveDir.y == 0) { lastMovedVector = new Vector2(lastHorizontalVector, lastVerticalVector); } } public void Move(InputAction.CallbackContext context) { moveDir = context.ReadValue<Vector2>().normalized; } void SpriteDirectionCheck() { // x < 0 = left // flip if (lastHorizontalVector < 0) { spriteRenderer.flipX = true; } else { spriteRenderer.flipX = false; } } }</code>
November 19, 2024 at 7:44 pm #16424::The issue is very likely that the
movement
variable is empty inProjectileWeapon
. That is what is causing theNullReferenceException
.How is your
movement
variable set inProjectileWeapon
? Are you still using thePlayerMovement
component onProjectileWeapon
?You can check out this 1-minute video to understand null reference exceptions better as well.
November 22, 2024 at 10:03 pm #16488November 22, 2024 at 10:54 pm #16490 -
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