Resolved This Script CRASHES Unity

Hey everyone-

So I have been scripting a system to make a siren. My idea is that a lit block moves back and forth when a key is pressed. The key "F" is the siren's on/off switch. Here is my script:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using System.Threading;
4. using UnityEngine;
5.  
6. public class Sirens1 : MonoBehaviour
7. {
8.     private bool Switch = false;
9.  
10.     void Start()
11.     {
12.        
13.     }
14.  
15.     void Update()
16.     {
17.         if (Input.GetKeyDown(KeyCode.F)) {
18.  
19.             Switch = !Switch;
20.  
21.             if (Switch == true) {
22.                 transform.Translate(10, 0, 0);
23.                 Invoke("Lights", 1);
24.             }
25.  
26.         }
27.  
28.      
29.     }
30.  
31.     void Lights()
32.     {
33.         Debug.Log("Hello!");
34.  
35.         transform.Translate(-10, 0, 0);
36.     }
37. }

The idea is that the light block will move and then wait. When I use "IEnumerator", this script doesn't work. So for the waiting system, I used "Invoke"

This script works okay, but you have to press "F" every time you want the siren to move. The intended function is pressing "F" once and the siren keeps going back and forth. So naturally, I change the "If" statement to a "While" statement.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using System.Threading;
4. using UnityEngine;
5.  
6. public class Sirens1 : MonoBehaviour
7. {
8.     private bool Switch = false;
9.  
10.     void Start()
11.     {
12.        
13.     }
14.  
15.     void Update()
16.     {
17.         if (Input.GetKeyDown(KeyCode.F)) {
18.  
19.             Switch = !Switch;
20.  
21.             while (Switch == true) {
22.                 transform.Translate(10, 0, 0);
23.                 Invoke("Lights", 1);
24.             }
25.  
26.         }
27.  
28.      
29.     }
30.  
31.     void Lights()
32.     {
33.         Debug.Log("Hello!");
34.  
35.         transform.Translate(-10, 0, 0);
36.     }
37. }

This would obviously be the answer. Ideally, the light block keeps moving back and forth once you press "F". But when I run the game, Unity crashes. This game has very few other scripts, and the app only breaks when I use "when" instead of "IF" in that one section.

I don't know WHY this happens, but it might be similar to how using "SLEEP" in Unity tends to crash the app. If someone could help me understand what is going wrong and provide me with a script that will have the Light block move back and forth when your press "F". When you click "F" again, the light block stops.

Thanks in advance.

 

When your code is in a loop, NOTHING else can happen in your C# code. You don't get more Update() calls in your class here, and nothing else gets Update() calls or any other chances to run, either. Since you don't change the condition of the

while

block inside the block, then once the condition is true it will be true forever. Unity will continue to run the loop until the OS is told to kill the process.

 

while loop never exists, since it blocks mainthread (so you cannot switch it back to false anymore)

look into Coroutines, they can work with while loops.
but note that you might accidentally start multiple coroutines..
https://docs.unity3d.com/Manual/Coroutines.html
https://docs.unity3d.com/ScriptReference/Coroutine.html

 

What you actually want is very close to your first version:

Code (CSharp):

1. void Update()
2. {
3.     if (Input.GetKeyDown(KeyCode.F)) {
4.         Switch = !Switch;
5.     }
6.     if (Switch == true) {
7.         Invoke("Lights", 1);
8.     }
9. }

You want to process the "if it's good to control the light" condition outside the moment of pressing the key. I just moved your second

if

condition to follow the key handling part.

 

thanks for your replies! I have solved the problem now, thanks to your help!

 

thanks for your replies! I have solved the problem now, thanks to your help! (I also understand why it broke)