fixing a variable value during coroutine

Questions & Answers
1

hello, i will briefly explain my situation:
i have a script that:

  • gets the mouse position twice;
  • calculates the magnitude and the
    angle of the line between the two
    points;
  • istantiates a prefab at the first
    position
  • a coroutine that scales the prefab
    along the line (var lengthC)

the problem is that when i istantiate a new object before the scaling of the other
object is complete, i suppose that the variable lengthC gets updated and the previous coroutine stops.
is there a way to get around it?
can i like call the variable inside the coroutine and while it is executing the variable will have a fixed value?

here is the code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SpawnaCresci : MonoBehaviour
{

    [SerializeField] GameObject myCube;
    [SerializeField] float width = 1f;
    [SerializeField] float height = 1f;
    [SerializeField] Vector3 inputPosA = Vector3.zero;
    [SerializeField] Vector3 inputPosB = Vector3.zero;
    [SerializeField] Vector3 result;
    [SerializeField] Vector3 avoidBehindCamera;
    private GameObject thisCube;
    private float lengthC;
    [SerializeField] float growFactor = 0.1f;

    // Use this for initialization
    void Start()
    {
        avoidBehindCamera.z = 10f;
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {

            inputPosA = Camera.main.ScreenToWorldPoint(Input.mousePosition + avoidBehindCamera);
        }

        if (Input.GetMouseButtonUp(0))
        {
            inputPosB = Camera.main.ScreenToWorldPoint(Input.mousePosition + avoidBehindCamera);

            SpawnAlongLine();
            
        }


    }

    void SpawnAlongLine()
    {
       // Vector3 posC = ((inputPosB - inputPosA) * 0.5F) + inputPosA;
        lengthC = (inputPosB - inputPosA).magnitude;
        float sineC = (inputPosB.y - inputPosA.y) / lengthC;
        float angleC = Mathf.Asin(sineC) * Mathf.Rad2Deg;
        if (inputPosB.x < inputPosA.x) { angleC = 0 - angleC; }

        Debug.Log("inputPosA" + inputPosA + " : inputPosB" + inputPosB + /*" : posC" + posC + */" : lengthC " + lengthC + " : sineC " + sineC + " : angleC " + angleC);

        thisCube = Object.Instantiate(myCube, inputPosA, Quaternion.identity);

        thisCube.transform.rotation = Quaternion.Euler(0, 0, angleC);
        thisCube.transform.parent = null;

        StartCoroutine(Scale());

    }

    IEnumerator Scale()
    {
        float timer = 0;

        while (lengthC > thisCube.transform.localScale.x)
              {
                timer = Time.deltaTime;
                thisCube.transform.localScale += new Vector3(1, 0, 0) * timer * growFactor ;
            thisCube.transform.localPosition += thisCube.transform.right * timer * growFactor * 0.5f;
            yield return null;
              }
       
    }
}
2

You can pass the value as a paramether to your coroutine. Or create local variable inside the coroutine and assign the value from lengthC at the beginning.

First solution is better in this case