Distance an object has travelled over a certain time?

Questions & Answers
1

Hi, i have a physics game, and in order for the loseGame condition to work, I need to detect if a game object has moved less than a specified distance over a specified time. can anybody point me in the right direction?

cheers.

ie: check how far the object has travelled in the last ‘x’ seconds, if it is less than ‘y’ units, do something.

2

I cant think of a straight forward way of doing this.

First you will want to work out the distance since the last update. So something like:

var distance: float=0;

function Update()
{
distance += Vector3.Distance(object.position, previousPosition);
previousPosition=object.Position;
}

Now what not clear to me is whether you wanting the player to have moved a total amount of time since he started or he has moved a at least x amount distance in the last y seconds.

If its the former then the above gives you everything you want. If its the later then you going to need something more elaberate.

You will need to sample a distance in time and work out what the distance is for the last number of samples.

So maybe something like:

	var object: GameObject;
	
	var NumberOfSamples: int=10;
	var distances: float[];
	var lastSampleSlot: int=0;
	var previousPosition: Vector3;
	
	function Start()
	{
		distances=new float[NumberOfSamples];
	}
	
	function Update()
	{
		var currentSampleSlot: int = Time.time % NumberOfSamples;
		if( currentSampleSlot != lastSampleSlot)
		{
		     distances[ currentSampleSlot] =0;
		}
		
		distances[ currentSampleSlot ] += Vector3.Distance(object.transform.position, previousPosition);
		previousPosition=object.transform.position;
		
		// sum all the values in the distances array to work out the distance in the last x samples secs.
		
		var TotalSampleDistance: float =0;
		for (var value: float in distances) 
		{        
			TotalSampleDistance += value;
		}
	}

For any given second, it works how far you have travelled in that second. It records that in the array. Everytime you move into a new slot, you clear out whatever was in there before.