Making interpolation check event-driven, instead of continuous

I'm trying to implement free flow combat (think arkham asylum), and one of the core building blocks of the system is adding movement to the attack- once I determine who the player is targeting, if that enemy is in range, I want to interpolate the player's transform from their current position to the enemy's position over a fixed duration, say 0.5s, then ensure that every attack starts with 0.5s of windup that will hide/dress up the movement.

The most obvious way to do this seems to be something like

Code (csharp):

1.  
2. void Update(){
3. if (bInterpToEnemy){
4. playerObject.position = Vector3.Lerp(start.position, end.position, ((Time.time - startTime)*speed)/length);
5. }
6. }
7.  

The problem is, you're only going to want to interpolate while attacking, which will be less than 20% of the game's total runtime, so 80% of the time I'll be making a useless check every frame - is there any way I can get this in a self-contained function, given the fact that location interpolation needs to be execute over multiple frames to look natural?

 

What you're looking for are called coroutines.

 

Ooh that works perfectly, thank you!