StartCoroutine function inside TriggerOnEnter2D not working - unity + kinect

Question

So i'm using Kinect with unity to track user's hand movements, and let the user's hand act as a mouse, I have written the code to detect a collision between a button (sprite object) and the hand cursor using OnTriggerEnter2D, but I want the hand cursor to remain on the button (sprite object) for atleast 3 seconds for it to be considered as a button click action. The WaitForSeconds coroutine doesn't seem to be working. What am i doing wrong?

public class MenuSelect : MonoBehaviour{

private string btnName;
private string themeName;

// Use this for initialization
void Start () 
{
    //gestureListener = Camera.main.GetComponent<GestureListener>();    
}

// Update is called once per frame
void Update () 
{

}

void OnTriggerEnter2D(Collider2D col)
{
    //print("Collision Detected");
    StartCoroutine(WaitTime(3));
    if(col.gameObject.tag == "Button")
    {
        btnName = col.gameObject.name;
        switch(btnName)
        {
            case "musicBtn":
                Application.LoadLevel("Menu_Music");
                break;

            case "startBtn":
                Application.LoadLevel("Menu_Select");
                break;

            case "instructBtn":
                print("Instruction Clicked");
                break;

            case "exitBtn":
                Application.Quit();
                break;

            case "themeBtn":
                Application.LoadLevel("Menu_Theme");
                break;

            case "backBtn":
                Application.LoadLevel("Menu_LoadScreen");
                break;
        }
    }

}

IEnumerator WaitTime(float waitTime)
{
    yield return new WaitForSeconds(waitTime);
    print("seconds up already");
}   }

Answer 1

The coroutine itself will pause, but the code that called StartCoroutine() will keep going. So in this case, WaitTime() will pause but OnTriggerEnter2D() will keep going.

What you probably want instead is for the entire button logic to go in the coroutine. Then it won't matter that OnTriggerEnter2D() keeps going, since starting the coroutine is all it does. At that point you should call the coroutine function something other than WaitTime() since it's doing a lot more than just waiting eg. WaitThenRespondToButton()

Answer 2

Your WaitTime Coroutine will not pause the evaluation of the following code. The Coroutine will be kicked off and logic will immediately continue. Your Coroutine is waiting 3 seconds and will call that print function wherever it resides but that's all it will do.

You should probably go with something like:

private float triggerEnterTime = 0;

void OnTriggerEnter2D(Collider2D col)
{
    triggerEnterTime = Time.time;
}

void OnTriggerStay2D(Collider2D col)
{
    // Too soon?
    if(Time.time - triggerEnterTime < 3)
    {
        // Might want to do something to indicate graphically that you're holding
        //     like a progress bar. For now, simply abort for this frame.
        return;
    }

    // Has been held for 3 seconds, evaluate it
    if(col.gameObject.tag == "Button")
    {
        btnName = col.gameObject.name;
        switch(btnName)
        {
            case "musicBtn":
                Application.LoadLevel("Menu_Music");
                break;

            case "startBtn":
                Application.LoadLevel("Menu_Select");
                break;

            case "instructBtn":
                print("Instruction Clicked");
                break;

            case "exitBtn":
                Application.Quit();
                break;

            case "themeBtn":
                Application.LoadLevel("Menu_Theme");
                break;

            case "backBtn":
                Application.LoadLevel("Menu_LoadScreen");
                break;
        }
    }
}

That should do the trick but something that might be cleaner is to define a "MenuItemBehavior" that will handle itself rather than some master switch statement.

Something like the following. I'd attach it individually to each button and then set "TargetScene" for each as well. This should work for most of them though you'd have to do something slightly different for "Instruction" and "Exit"

public class SceneMenuItemController : MonoBehaviour
{
    public string TargetScene;

    private float triggerEnterTime = 0;

    void OnMouseUpAsButton()
    {
        if (!string.IsNullOrEmpty(TargetScene))
        {
            Application.LoadLevel(TargetScene);
        }
    }

    void OnTriggerEnter2D(Collider2D col)
    {
        triggerEnterTime = Time.time;
    }

    void OnTriggerStay2D(Collider2D col)
    {
        // Too soon?
        if(Time.time - triggerEnterTime < 3)
        {
            // Might want to do something to indicate graphically that you're holding
            //     like a progress bar. For now, simply abort for this frame.
            return;
        }

        if (!string.IsNullOrEmpty(TargetScene))
        {
            Application.LoadLevel(TargetScene);
        }
    }
}