Simplest way to change Scene with a collider and a key press?

Hello!

I have a simple code:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using UnityEngine.SceneManagement;
4.  
5. public class FrontDoorOutside : MonoBehaviour {
6.  
7.         void OnTriggerEnter(Collider other)
8.  
9.                
10.             {
11.                 SceneManager.LoadScene (2);
12.             }
13.         }
14.    
15.    
16.  
17.  
18.    
19.  
20.  

My character is a rigidbody with a collider and if he enters the object that has the script above attached, he will change the scene. What would be the simplest way to add a query for a key to be pressed such as if(Input.GetKeyDown(KeyCode.E));. I tried everything but can't get a solution.

 

Since the physics events only fire on FixedUpdates, the chances of an onkeydown event happening at the same frame the physics event fires is not reliable.

A very simple implementation could be like this:

Code (CSharp):

1. public KeyCode changeScenesKey;
2. bool colliding;
3.  
4. private void OnTriggerEnter(Collider other) {
5.     colliding = true;
6. }
7. private void OnTriggerExit(Collider other) {
8.     colliding = false;
9. }
10.  
11. private void Update() {
12.     if(colliding && Input.GetKeyDown(changeScenesKey)) {
13.         SceneManager.LoadScene(2)
14.     }
15. }

 

try this

Code (CSharp):

1. public class FrontDoorOutside : MonoBehaviour
2. {
3.     bool MustLoadScene = false;
4.  
5.     void OnTriggerEnter(Collider other)
6.  
7.  
8.     {
9.         if (MustLoadScene == true)
10.         {
11.             MustLoadScene = false;//we dont want to load the scene multible times
12.             SceneManager.LoadScene(2);
13.         }
14.        
15.     }
16.  
17.     void Update()
18.     {
19.         if (Input.GetKeyDown(KeyCode.E)) MustLoadScene = true;
20.     }
21. }
22.    

 

this one works perfect. thanks

this one requires to press the key right at the same time you touch the collider. when I stand in it it won't work.

 

would it be possible to add a timer before the scene change?

I thought about something like this but it doesn't work. why not?

Code (CSharp):

1.     public KeyCode changeScenesKey;
2.     bool colliding;
3.     public float Timer = 10f;
4.  
5.     private void OnTriggerEnter(Collider other)
6.     {
7.         colliding = true;
8.  
9.     }
10.     private void OnTriggerExit(Collider other)
11.     {
12.         colliding = false;
13.  
14.  
15.     }
16.  
17.     private void Update ()
18.     {
19.        
20.  
21.         if (colliding && Input.GetKeyDown (changeScenesKey))
22.         {
23.  
24.             Timer = Timer - Time.deltaTime;
25.             {
26.                 if(Timer >= 0)
27.             {
28.                    
29.             }
30.                 if(Timer <= 0)
31.                     {
32.                         SceneManager.LoadScene (2);
33.                     }
34.                 }
35.             }
36.         }
37. }

 

line 21 is evaluate to "true" max 1 time per keypress right?

 

That is correct, which means the timer will not increment properly.

My favorite way to wait for things is to use Coroutines:

Code (CSharp):

1. public KeyCode changeScenesKey;
2. public float Timer = 10f;
3.  
4. private bool colliding;
5. private bool sceneChanging;
6.  
7. private void OnTriggerEnter(Collider other) {
8.     colliding = true;
9. }
10. private void OnTriggerExit(Collider other) {
11.     colliding = false;
12. }
13.  
14. private void Update() {
15.     if(!sceneChanging && colliding && Input.GetKeyDown(changeScenesKey)) {
16.         sceneChanging = true;
17.         StartCoroutine(sceneChangeCoroutine());
18.     }
19. }
20.  
21. private IEnumerator sceneChangeCoroutine() {
22.     yield return new WaitForSeconds(Timer);
23.     sceneChanging = false;
24.     SceneManager.LoadScene(2);
25. }

make sure you have "using System.Collections" at the top in order to use IEnumerator.

Here's how you can do it without coroutines:

Code (CSharp):

1. public KeyCode changeScenesKey;
2. public float Timer = 10f;
3.  
4. private bool colliding;
5. private bool sceneChanging;
6. private float elapsedTime;
7.  
8. private void OnTriggerEnter(Collider other) {
9.     colliding = true;
10. }
11. private void OnTriggerExit(Collider other) {
12.     colliding = false;
13. }
14.  
15. private void Update() {
16.     if(sceneChanging) {
17.         elapsedTime += Time.deltaTime;
18.         if(elaspedTime >= Timer) {
19.             SceneManager.LoadScene(2);
20.             elapsedTime = 0;
21.             sceneChanging = false;
22.         }
23.     } else if(colliding && Input.GetKeyDown(changeScenesKey)) {
24.         sceneChanging = true;
25.     }
26. }

 

Without Coroutine is easier to understand for me at the moment. Now I want to get my character to be unable to move during the timer since it is supposed to act like a short loading screen with a panel or image infront of the camera that fades to black. Should I try to get the rigidbody of my character to disabled or should I disable the movement script for that? How do I get them?

 

There are many ways you could organize the code communication.

One way which is probably easiest to understand is to have the scene changer script get the player's component and disable it just after setting "sceneChanging = true". You could get the player script by using GameObject.FindGameObjectWithTag("Player") to get the player gameobject, or FindObjectOfType<MovementScript>() to directly find the script on the player (assuming there is only one of these in the scene).

Ideally, the scene changer script wouldn't know about the player script at all, and would just do its thing. The player would check a value before acting on input. However doing that kind of organization is more complex and would require a longer explanation.

 

Thank you Jeffrey, I got it!