Multiple Lerps using Coroutines

Unity Engine
1

Hello All,

This is my first post here on the forums and I’m fairly new to Unity, so take it easy on me.

I’ve been writing a simple script to move an object from one way point to the next using the Lerp command. All worked fine with just one way point, but when I implemented a for loop to handle multiple way points, things got a little tricky.

Here is my script:

// Public Variables
public var Waypoints : GameObject[];
public var Speed : float;

// Private Variables
private var isFinished : boolean;

function Update() 
{
	if(!isFinished)
		DoCo();
}

function LerpFunc(num : int) : IEnumerator 
{
	this.transform.position = Vector3.Lerp(this.transform.position, Waypoints[num].transform.position, Time.time * Speed);
}

function DoCo()
{
	for(i=0; i <= Waypoints.Length - 1; i++)
	{
		Debug.Log("Lerping to Waypoint " + i.ToString());
		yield LerpFunc(i);
	}
	
	isFinished = true;
}

Let me explain it. First, I add some GameObjects to the scene to serve as way points for the character and I assign them to the Waypoints array on the character. Second, the DoCo() function is called once and we loop through each way point and Lerp to it. I use the yield command to wait for the Lerp to complete before continuing with the loop.

However, when I test the scene, we are instantly at the end of the loop and the character is moved to a position close to the last way point, but not exactly on it.

I’m kind of at a loss here, and any help would be appreciated!

2

Some things: You shouldn’t be using Update at all, Update is for things that happen every frame. Don’t use Time.time in Lerp (see here). You can just write “transform.position” instead of “this.transform.position”. You should really follow the convention of using lowercase for variable names (uppercase for classes and methods), and write out complete legible names, don’t abbreviate, it just makes things harder to understand.

–Eric