Time factor is changing and getting wierd when I leave the Unity program open too long

2D
1

I am having an odd problem. I am working on a 2d game. I have some sprites that I am having move on a preset pattern using lerp.

To be exact here is one of the statements:

this.transform.position = Vector2.Lerp(this.transform.position,Vector2(this.transform.position.x-1,this.transform.position.y) , speed);

If I open Unity (Windows 7 / Unity 4.6) at first everything works exactly as I programmed it. But after Ive been working on things for a couple of hours or even if I just open Unity and walked away for a few hours and came back to it, all the sudden the sprites that I have moving using the lerp function no longer move the normal way. They start moving much faster or in other sporadic and odd ways. Also I don’t think its just lerp I have a sprite moving using a

this.transform.Rotate (Vector3.forward * -1);

and after a while it starts rotating in jerky ways vs smooth.

Whenever this happens all I have to do is restart unity and everything works normal again, at least for a while.

What is very strange is I need to close Unity and restart it to fix it. If I just hit the play button again things are still weird. I would think every time you hit the play button it should reset all the variables and start the game fresh, so it does not seem right that I need to close the program and restart it to get back to normal.

Does anyone know what might be causing this?

2

Well, I seemed to have figure it out. The problem was the move scripts needed to be in Fixed Update vs Update. That made all the difference.

3

FixedUpdate should be used when dealing with physics, like applying force to a rigidbody.

You can just multiply your speed by Time.deltaTime inside the Update function

http://unity3d.com/learn/tutorials/modules/beginner/scripting/delta-time

4

Definitely don’t use FixedUpdate if you’re not using physics. It doesn’t match the screen update rate, so it won’t look as good.

–Eric