Why the lerp is not starting over again increasing/decreasing the float ?

Unity Engine
,
1 
using System.Collections;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

public class DistanceCheck : MonoBehaviour
{
    float lerpDuration = 3;
    public GameObject descriptionTextImage;
    public TextMeshProUGUI text;

    private Animator anim;
    private bool slowDownOnExit = false;

    private float timeElapsed = 0;
    private float startValue = 1;
    private float endValue = 0;
    private float valueToLerp = 0;
    private bool resetV = false;

    // Start is called before the first frame update
    void Start()
    {
        anim = transform.GetComponent<Animator>();
    }

    // Update is called once per frame
    void Update()
    {
        if (slowDownOnExit)
        {
            if (timeElapsed < lerpDuration)
            {
                valueToLerp = Mathf.Lerp(startValue, endValue, timeElapsed / lerpDuration);
                anim.SetFloat("Forward", valueToLerp);
                timeElapsed += Time.deltaTime;
            }
            anim.SetFloat("Forward", valueToLerp);
            descriptionTextImage.SetActive(true);
            text.text = "I can't move that far by foot. I need to find some transportation to move any further.";

            if(valueToLerp == 0 && resetV == false)
            {
                timeElapsed = 0;
                startValue = 0;
                endValue = 1;
                resetV = true;
            }

            if(valueToLerp == 1 && resetV)
            {
                timeElapsed = 0;
                startValue = 1;
                endValue = 0;
                resetV = false;
            }
        }
        else
        {
            text.text = "";
            descriptionTextImage.SetActive(false);
        }
    }

    private void OnTriggerExit(Collider other)
    {
        if (other.name == "CrashLandedShipUpDown")
        {
            slowDownOnExit = true;
        }
    }
}

I want to make that when the valueToLerp is 0 or when the lerp finished first time increase the valueToLerp back to 1 with the same lerp then when reaching to 1 start the lerp again back to 0 and so on nontsop like a “PingPong” but without using pingpong. I tried to use the resetV flag helper but the valueToLerp get to 0 and never continue back up to 1 again.

2

Why are you not using the correct tool for the job?

Could you just make an animation and be done with it??

Another great general-purpose solution to move stuff would be to use a tweening package like ITween or DOTween or LeanTween. They get you out of a lot of fiddly debugging when used properly.

Either way, if you want to untangle all those myriad entangled state variables above, here’s how to start thinking about it.

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

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 Debug.Log() 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 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.

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.

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: https://discussions.unity.com/t/700551 or this answer for Android: https://discussions.unity.com/t/699654

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:

https://discussions.unity.com/t/839300/3

1 Like
3 
valueToLerp == 0

Floats are too inaccurate to reliably compare them like that

use Mathf.Approximately to compare floats instead