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Question having trouble with LeanTween and coroutines

Discussion in 'Scripting' started by ViottiViolet, May 20, 2023.

  1. ViottiViolet


    May 20, 2023
    ive been trying to use LeanTween in order to animate my text and make it pulse to what will hopefully be a rhythm, but right now it just has to pulse in consistent intervals. i tried to implement a coroutine to handle this, but as a very new coder im guessing i havent gotten the hang of how it works yet. when i press play, the text will pulse once before a "NullReferenceException: object reference not set to instance of object" appears and stops everything, specifically on the first LeanTween.scale() line. heres my code

    Code (CSharp):
    1. using System.Collections;
    2. using System.Collections.Generic;
    3. using UnityEngine;
    5. public class PulseTween : MonoBehaviour
    6. {
    8.     [Header("PULSE PARAMETERS")]
    9.     [SerializeField] private bool canPulse = true;
    10.     [SerializeField] private GameObject text;
    12.     [SerializeField] private float pulseMin = 1.25f;
    13.     [SerializeField] private float pulseMax = 1.5f;
    14.     [SerializeField] private float pulseSpeed = 1.0f;
    15.     [SerializeField] private LeanTweenType easeIn;
    16.     [SerializeField] private LeanTweenType easeOut;
    18.     // Start is called before the first frame update
    19.     void Start()
    20.     {
    22.     }
    24.     // Update is called once per frame
    25.     void Update()
    26.     {
    27.         if (canPulse) StartCoroutine(handlePulse());
    28.     }
    30.     IEnumerator handlePulse()
    31.     {
    33.         LeanTween.scale(text, new Vector3(pulseMax, pulseMax, 0), pulseSpeed/10).setEase(easeIn);
    34.         LeanTween.scale(text, new Vector3(pulseMin, pulseMin, 0), pulseSpeed/2).setEase(easeOut);
    35.         yield return new WaitForSeconds(pulseSpeed);
    37.     }
    38. }
    i attach the component to a TextMeshPro and then put that same TMP into the "text" object by dragging it to the inspector, and then i adjust the other variables as needed. i dont see why "text" should be null or contain no object at any point of this script, but again i suspect its something to do with how im using the coroutine

    thank you to anyone who can help me with this
  2. Kurt-Dekker


    Mar 16, 2013
    Nothing matters until you fix the nullref.

    The answer is ALWAYS the same.

    How to fix a NullReferenceException error

    Three steps to success:
    - Identify what is null <-- any other action taken before this step is WASTED TIME
    - Identify why it is null
    - Fix that

    Once that is fixed, if it still doesn't work then it is...

    Time to start debugging! Here is how you can begin your exciting new debugging adventures:

    You must find a way to get the information you need in order to reason about what the problem is.

    Once you understand what the problem is, you may begin to reason about a solution to the problem.

    What is often happening in these cases is one of the following:

    - the code you think is executing is not actually executing at all
    - the code is executing far EARLIER or LATER than you think
    - the code is executing far LESS OFTEN than you think
    - the code is executing far MORE OFTEN than you think
    - the code is executing on another GameObject than you think it is
    - you're getting an error or warning and you haven't noticed it in the console window

    To help gain more insight into your problem, I recommend liberally sprinkling
    statements through your code to display information in realtime.

    Doing this should help you answer these types of questions:

    - is this code even running? which parts are running? how often does it run? what order does it run in?
    - what are the names of the GameObjects or Components involved?
    - what are the values of the variables involved? Are they initialized? Are the values reasonable?
    - are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

    Knowing this information will help you reason about the behavior you are seeing.

    You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as

    If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

    You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

    You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

    You could also just display various important quantities in UI Text elements to watch them change as you play the game.

    Visit Google for how to see console output from builds. If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: or this answer for Android:

    If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

    Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

    Here's an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

    "When in doubt, print it out!(tm)" - Kurt Dekker (and many others)

    Note: the
    function is an alias for Debug.Log() provided by the MonoBehaviour class.