Creating a delay by using Invoke

Question

Is it possible to delay the effects of a script that is attached to a game object?

I have 2 characters in a scene, both receiving live motion capture data, so they are both animated identically. I have rotated one by 180 degrees and placed it in front of the other one, to create the impression that they are copying/mirroring each other.

Each has several scripts attached to them, of course...

Now, I would like to be able to delay one character a bit (e.g. 1 sec) to make it look more realistic, as if one character is observing the other character and then copying its exact movements.

Is it possible to do this by somehow using the Invoke method on the other character's Update perhaps? Or any other possibilities to achieve what I described?

EDIT :: I used a buffering mechanism, as suggested by all the helpful comments and answers, instead of delaying, because delaying would have resulted in the same network data being used, except after a delay, but I needed the same old data being used to animate a second character to create the impression of a delayed copying...

private Queue<Vector3[]> posQueue;
private Queue<Quaternion[]> rotQueue;
int delayedFrames = 30;

void Start()
{
    posQueue = new Queue<Vector3[]>();
    rotQueue = new Queue<Quaternion[]>();
}

void Update()
{
    Vector3[] latestPositions;
    Quaternion[] latestOrientations;

    if (mvnActors.getLatestPose(actorID-1, out latestPositions, out latestOrientations))
    {
        posQueue.Enqueue(latestPositions);
        rotQueue.Enqueue(latestOrientations);

        if ((posQueue.Count > delayedFrames) && (rotQueue.Count > delayedFrames))
        {
            Vector3[] delayedPos = posQueue.Dequeue();
            Quaternion[] delayedRot = rotQueue.Dequeue();

            updateMvnActor(currentPose, delayedPos, delayedRot);
            updateModel(currentPose, targetModel);
        }
    }
}

Answer 1

This seems like it would be straightforward to implement with some sort of event-queue-style thing.

I'm assuming that you have a method on your characters that gets called frequently by your data source, and that you immediately interpret that data into animation. This could be trivially flipped to work with polling, etc.

So, starting with something like...

public void setMoCap(MoCapObject newData){
  animateImmediately(newData);
}

It would be pretty easy to give each animated character a Queue<MoCapObject> moCapQueue to track that data, and a float animationDelay to determine how long they wait to respond.

public void setMoCap(MoCapObject newData){
  moCapQueue.Enqueue(newData);
}

Then, in your update method, respond if the delay has passed.

public void Update(){
  if(moCapQueue.Count > 0)
  {
    MoCapObject nextData = moCapQueue.Peek();

    if(nextData .timestamp <= (Time.time + animationDelay))
    {
      nextData = moCapQueue.Dequeue();
      animateImmediately(nextData );
    }
  }
}

This approach assumes that your data, however it comes in (MoCapObject, here) has a timestamp. If not, you'll have to do that manually (perhaps with two parallel Queues or a new wrapper object to enqueue).

It also doesn't take into account animation conflicts or any of the other myriad issues this kind of project has, but it shouldn't be any different from an existing solution on that front. Just delays response.

Also you may want to enable your "consume queued data" check to process more than one data point per frame.

Answer 2

Since Invoke() is mentioned, I'm assuming you're looking for a simple solution to just introduce some delay.The way to introduce delay in unity is Coroutines. Here's the Pseudocode :

IEnumerator AnimateCharacters()
{
    Animate first character.
    // Introduce delay using yield return
     yield return new waitforSeconds(number of seconds to delay);
   Animate second character

}

This will animate first character, delays executing next step by specified number of seconds, and then, executes the next step which is animation. You'd call this from a method you've set up to handle input like this:

void OnInput()
{
   startCoRoutine("AnimateCharacters");
}