koobas.hobune.stream
Coroutines and Lerp - how to make them friends?
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.
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));
I do like to point out that by using this code, the position where the object ends up may be inconsistent. For example, I needed my Gameobject to stop at exactly 1.12345 in the yPos. This code does not guarantee that since one possible reason is that elapsedTime < duration doesn't necessarily always break on exactly the same elapsedTime value. Just a heads up for future devs who run into this thread searching for answers as well :))
Did you try: At the end of path, just sync position?
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();
}
}
I noticed the WaitForEndOfFrame() as well. Is there an advantage of that over yield return null?
@Electric$$anonymous$$onk
They simply return at different points during a frame. WaitForEndOfFrame() obviously returns at the end of the frame. Returning null will return during main coroutine updates (which I believe occurs between Update() and LateUpdate(), which also means it occurs before rendering.)
Also note that WaitForEndOfFrame() is a class object, so caching it in a variable and reusing it will create slightly less overhead in performance-heavy operations.
I was placing the yeld return OUTSIDE the while, and It was behaving very weirdly. Now yous aved my life cause I burnt half afternoon trying to figure out the hell was going on. Can you explain why it needs to be inside the while, even further if it returns nothing?
