Blink object on collision

Question

I have a fish where the objective is to avoid Enemy fish. Now when the player fish hits the enemy fish i want the player fish to blink twice (n number if possible)

     void BlinkPlayer(int numBlink)
     {
         for(int i=0; i < numBlink; i++)
         {
             transform.renderer.enabled = false;
             StartCoroutine( Wait (.2f));
             transform.renderer.enabled = true;
             StartCoroutine( Wait (.2f));
         }
     }
     
     IEnumerator Wait(float seconds)
     {
         Debug.Log ("Wait");
         yield return new WaitForSeconds(seconds);    
     }

Then im calling BlinkPlayer() from OnCollisionEnter() Doesn't matter how lrge value I give for Wait() my player fish doesn't blink. I also tried taking out the for() loop inside BlinkPlayer(), but that didn't work out either. Although it does print "Wait" in console.

Any idea what am I doing wrong? I am using unity 4.1 if that matters.

Answer 1

Best Answer

Answer by rutter · Nov 06, 2013 at 12:20 AM

You're close, but missing one crucial detail.

Unity's docs say that StartCoroutine returns "immediately". The function making the call doesn't wait. It's only the coroutine itself that waits.

You could probably re-organize it something like this:

 void BlinkPlayer(int numBlinks) {
     StartCoroutine(DoBlinks(numBlinks, 0.2f));
 }
 
 IEnumerator DoBlinks(int numBlinks, float seconds) {
     for (int i=0; i<numBlinks*2; i++) {
     
         //toggle renderer
         renderer.enabled = !renderer.enabled;
         
         //wait for a bit
         yield return new WaitForSeconds(seconds);
     }
     
     //make sure renderer is enabled when we exit
     renderer.enabled = true;
 }

Edit: It occurred to me that it might be easier to control the coroutine by duration (in seconds), as opposed to a fixed number of blinks. Something like this...

 public class Blink : MonoBehaviour {
     void Start () {
         StartCoroutine(DoBlinks(3f, 0.2f));
     }
     
     IEnumerator DoBlinks(float duration, float blinkTime) {
         while (duration > 0f) {
                 duration -= Time.deltaTime;
      
            //toggle renderer
            renderer.enabled = !renderer.enabled;
      
            //wait for a bit
            yield return new WaitForSeconds(blinkTime);
         }
  
         //make sure renderer is enabled when we exit
         renderer.enabled = true;
     }
 }

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blackcloud1971 · Nov 06, 2013 at 03:22 AM 0

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thanks both of you for the code, you guys are right about the co-routine calling. Right now at least my fish is disappearing-appearing. But the problem is it's NOT blinking. Now the player is getting hidden & after about 1 sec it's re-appearing again. No matter how small value i provide for WaitForSeconds() it does not seem to be working. Please let me know if I should create a new question for this one.

Huacanacha · Nov 06, 2013 at 03:28 AM 0

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Right, then the problem is that you are disabling the whole fish renderer and not just the eyes. You may want to perform an animation ins$$anonymous$$d of hiding components. How exactly do you intend to make the fish blink?

blackcloud1971 · Nov 06, 2013 at 03:33 AM 0

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Yes I actually have a picture of a fish on a Quad as this is a 2D game. I'm disabling the renderer of that quad. And for blinking I want it to appear and disappear couple of times in a very short time

Huacanacha · Nov 06, 2013 at 03:36 AM 0

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You want the whole quad to disappear, or just the texture and have a blank quad displayed? You could swap out or disable the texture rather than turning off the whole renderer, which will just make the whole object disappear.

Or is the problem that it is disappearing for too long a time?

blackcloud1971 · Nov 06, 2013 at 03:39 AM 0

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I actually didn't think about disabling just the texture. I don't $$anonymous$$d doing that because my quad has the same color as background so it should look the same.

And yes the problem is it's disappearing for too long before re-appearing again

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Blink object on collision

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