Coroutines and Lerp - how to make them friends?

Questions & Answers
1

Hi there, so I’ve spent a bit of my time getting my head around coroutines which is a fantastic tool to have in your armoury. However, I’m confused by how to use a Vector3.Lerp within a coroutine - separately, I understand how they work, but I’m a little fuzzy as to how to make them work together. I’ve been pointed to a javascript piece of code here but this doesn’t make things much clearer for me. As always, any help is truly appreciated.

2

The two functions are completely orthogonal- there’s no reason whatsoever why they can’t work together!

In fact, they are particularly useful in conjunction. Here’s a simple bit of code for making an object move to a new position over a period of n seconds.

function MoveToPosition(newPosition : Vector3, time : float)
{
    var elapsedTime : float = 0;
    var startingPos : Vector3 = transform.position;
    while (elapsedTime < time)
    {
        transform.position = Vector3.Lerp(startingPos, newPosition, (elapsedTime / time));
        elapsedTime += Time.deltaTime;
        yield;
    }
}

Simply call that function with StartCoroutine, and it’ll all work!

StartCoroutine(MoveToPosition(new Vector3(0, 10, 0), 5));
3

And for C#

    private IEnumerator FadeOut(float alphaStart, float alphaFinish, float time)
    {
      if (bgTexture == null)
        yield return null;

     float elapsedTime = 0;
     bgTexture.alpha = alphaStart;

     while (elapsedTime < time)
     {
       bgTexture.alpha = Mathf.Lerp(bgTexture.alpha, alphaFinish, (elapsedTime / time));
         elapsedTime += Time.deltaTime;
       yield return new WaitForEndOfFrame();
     }
    }