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C# Coroutine doesnt works in Unity

Im trying to make a basic platformer game and my level controller script isnt working, it needs to load loading scene first and then nextlevel but it constantly loads the nextlevel
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class LevelController : MonoBehaviour
{
[SerializeField] string nextLevel;
private Gem[] gems;
void OnEnable()
{
gems = FindObjectsOfType<Gem>();
}
IEnumerator Wait()
{
yield return new WaitForSeconds(3);
}
void Update()
{
if (ReadyToNextLevel())
{
SceneManager.LoadScene("Loading");
StartCoroutine(Wait());
SceneManager.LoadScene(nextLevel);
}
}
bool ReadyToNextLevel()
{
foreach (var gem in gems)
{
if (gem.gameObject.activeSelf)
{
return false;
}
}
return true;
}
}

There are two big issues in your code.
Starting a Coroutine does not delay the method that started the routine!
If you want something happening after the Coroutine is finished you need to either move it into the routine itself or use a callback.
However, the thing is: You are loading a new scene, namely the "Loading" scene -> The current scene is unloaded -> the object this script is on gets destroyed -> the routine would no further executed.
Except your object is DontDestroyOnLoad which seems not the case from your code.
So in order to solve both you will need to make sure this object is not destroyed when another scene is loaded, at least not until it finished the loading process.
You could do this like e.g.
public class LevelController : MonoBehaviour
{
[SerializeField] string nextLevel;
private Gem[] gems;
void OnEnable()
{
gems = FindObjectsOfType<Gem>();
// Makes sure this is not destroyed when another scene is load
DontDestroyOnLoad(gameObject);
}
bool alreadyLoading;
IEnumerator Wait(Action whenDone)
{
yield return new WaitForSeconds(3);
// invoke the callback action
whenDone?.Invoke();
}
void Update()
{
if (ReadyToNextLevel() && ! alreadyLoading)
{
alreadyLoading = true;
SceneManager.LoadScene("Loading");
StartCoroutine(Wait(() =>
{
// This will be done after the routine finished
SceneManager.LoadScene(nextLevel);
// Now we don't need this object anymore
Destroy(gameObject);
}));
}
}
bool ReadyToNextLevel()
{
foreach (var gem in gems)
{
if (gem.gameObject.activeSelf)
{
return false;
}
}
return true;
}
}

EDIT: see derHugo's answer. They are more familiar with Unity than I am and point out that your script will be unloaded on scene change.
Your Wait() coroutine yields immediately, so StartCoroutine(Wait()) will return immediately and load the next scene.
If you want to wait three seconds before loading, then put the load inside the coroutine.
Like this:
private bool isLoading;
void Update()
{
if (!isLoading && ReadyToNextLevel())
StartCoroutine(LoadNextLevel());
}
IEnumerator LoadNextLevel()
{
isLoading = true;
SceneManager.LoadScene("Loading");
yield return new WaitForSeconds(3);
SceneManager.LoadScene(nextLevel);
isLoading = false;
}
See Coroutine help for more details

there are two reasons why this doesn't work, firstly when you load into the loading scene the gameObject is destroyed because you haven't told it to DontDestroyOnLoad, so the script will be sort of 'deleted' from the current scene. Second of all, when you call the coroutine, it calls the coroutine and then immediately continuous on to the next line of code, it doesn't wait for the coroutine to finish before moving on. I think derHugo covered how to fix these.

How to preserve the full state of objects between scenes?

When loading a new Scene I run into the trouble of having my mouse drag not carry over to the next scene and having to re-click when the new scene is loaded.
I would like the mouse click to carry over seamlessly to the next scene without the player noticing and more generally I would like to know how best to preserve certain game objects and make them carry over to the next scene.
In essence, what I'm trying to do is have the entire game act like one big scene that the player can play trough but still be broken down into smaller scenes that could be accessed or transformed into levels at a later stage.
Thanks in advance.
This is the code I'm currently using
using UnityEngine;
using System.Collections;
using UnityEngine.Profiling;
public class MoveBall : MonoBehaviour
{
public static Vector2 mousePos = new Vector2();
private void OnMouseDrag()
{
mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
transform.position = mousePos;
DontDestroyOnLoad(this.gameObject);
}
}
Bellow is the script that is responsible for the loading of the scene:
public class StarCollision : MonoBehaviour
{
private bool alreadyScored = false;
private void OnEnable()
{
alreadyScored = false;
}
private void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.CompareTag("White Ball"))
{
if (!alreadyScored)
{
ScoreScript.scoreValue += 1;
StartCoroutine(ChangeColor());
alreadyScored = true;
}
}
if (ScoreScript.scoreValue > 4)
{
SceneManager.LoadScene(1);
}
}
private IEnumerator ChangeColor()
{
ScoreScript.score.color = Color.yellow;
yield return new WaitForSeconds(0.1f);
ScoreScript.score.color = Color.white;
gameObject.SetActive(false);
}
}

I think the main reason why it doesn't work is that you probably also have another Camera in the new Scene.
The OnMouseDrag rely on the Physics system internally using the objects Collider and raycasts from the Camera. Now if you switch Scene I'ld guess the one Camera gets disabled so your drag gets interrupted.
Also using LoadScene instead of LoadSceneAsync causes a visible lag and might also be related to the issue.
I have a maybe a bit more complex solution but that is what I usually do:
1. Have one Global Scene "MainScene"
This Scene contains stuff like e.g. the MainCamera, global ligthning, global manager components that should never be destroyed anyway.
2. Use additive async Scene loading
You said you do not want your user to not note when the scene switches so I would recommend using SceneManager.LoadSceneAsync anyway.
Then in order to not unload the before mentioned MainScene you pass the optional parameter LoadSceneMode.Additive. This makes the new Scene be loaded additional to the already present one. Then later you only have to exchange those by unloading the previously additive loaded scene.
I created a very simple static manager for this:
public static class MySceneManager
{
// store build index of last loaded scene
// in order to unload it later
private static int lastLoadedScene = -1;
public static void LoadScene(int index, MonoBehaviour caller)
{
caller.StartCoroutine(loadNextScene(index));
}
// we need this to be a Coroutine (see link below)
// in order to correctly set the SceneManager.SetActiveScene(newScene);
// after the scene has finished loading. So the Coroutine is required
// in order to wait with it until the reight moment
private static IEnumerator loadNextScene(int index)
{
// start loading the new scene async and additive
var _async = SceneManager.LoadSceneAsync(index, LoadSceneMode.Additive);
// optionally prevent the scene from being loaded instantly but e.g.
// display a loading progress
// (in your case not but for general purpose I added it)
_async.allowSceneActivation = false;
while (_async.progress < 0.9f)
{
// e.g. show progress of loading
// yield in a Coroutine means
// "pause" the execution here, render this frame
// and continue from here in the next frame
yield return null;
}
_async.allowSceneActivation = true;
// loads the remaining 10%
// (meaning it runs all the Awake and OnEnable etc methods)
while (!_async.isDone)
{
yield return null;
}
// at this moment the new Scene is supposed to be fully loaded
// Get the new scene
var newScene = SceneManager.GetSceneByBuildIndex(index);
// would return false if something went wrong during loading the scene
if (!newScene.IsValid()) yield break;
// Set the new scene active
// we need this later in order to place objects back into the correct scene
// if we do not want them to be DontDestroyOnLoad anymore
// (see explanation in SetDontDestroyOnLoad)
SceneManager.SetActiveScene(newScene);
// Unload the last loaded scene
if (lastLoadedScene >= 0) SceneManager.UnloadSceneAsync(lastLoadedScene);
// update the stored index
lastLoadedScene = index;
}
}
This MySceneManager is a static class so it is not attached to any GameObject or Scene but simply "lives" in the Assets. You can now call it from anywhere using
MySceneManager.LoadScene(someIndex, theMonoBehaviourCallingIt);
The second parameter of type MonoBehaviour (so basically your scripts) is required because someone has to be responsible for running the IEnumerator Coroutine which can't be done by the static class itself.
3. DontDestroyOnLoad
Currently you are adding any GameObject you dragged at any time to DontDestroyOnLoad. But you never undo this so anything you touched meanwhile will be carried on from that moment ... forever.
I would rather use e.g. something like
public static class GameObjectExtensions
{
public static void SetDontDestroyOnLoad(this GameObject gameObject, bool value)
{
if (value)
{
// Note in general if DontDestroyOnLoad is called on a child object
// the call basically bubbles up until the root object in the Scene
// and makes this entire root tree DontDestroyOnLoad
// so you might consider if you call this on a child object to first do
//gameObject.transform.SetParent(null);
UnityEngine.Object.DontDestroyOnLoad(gameObject);
}
else
{
// add a new temporal GameObject to the active scene
// therefore we needed to make sure before to set the
// SceneManager.activeScene correctly
var newGO = new GameObject();
// This moves the gameObject out of the DontdestroyOnLoad Scene
// back into the currently active scene
gameObject.transform.SetParent(newGO.transform, true);
// remove its parent and set it back to the root in the
// scene hierachy
gameObject.transform.SetParent(null, true);
// remove the temporal newGO GameObject
UnityEngine.Object.Destroy(newGO);
}
}
}
This is an Extension Method which allows you to simply call
someGameObject.SetDontDestroyOnLoad(boolvalue);
on any GameObject reference.
Then I changed your script to
public class MoveBall : MonoBehaviour
{
public static Vector2 mousePos = new Vector2();
// On mouse down enable DontDestroyOnLoad
private void OnMouseDown()
{
gameObject.SetDontDestroyOnLoad(true);
}
// Do your dragging part here
private void OnMouseDrag()
{
// NOTE: Your script didn't work for me
// in ScreenToWorldPoint you have to pass in a Vector3
// where the Z value equals the distance to the
// camera/display plane
mousePos = Camera.main.ScreenToWorldPoint(new Vector3(
Input.mousePosition.x,
Input.mousePosition.y,
transform.position.z)));
transform.position = mousePos;
}
// On mouse up disable DontDestroyOnLoad
private void OnMouseUp()
{
gameObject.SetDontDestroyOnLoad(false);
}
}
And in your StarCollision script you only have to exchange
SceneManager.LoadScene(1);
with
MySceneManager.LoadScene(2, this);
Demo
For a little demonstration I "faked" it using two simple scripts
This one in the Main scene
public class LoadFirstscene : MonoBehaviour
{
// Start is called before the first frame update
private void Start()
{
MySceneManager.LoadScene(1, this);
}
}
And this one in the other scenes
public class LoadNextScene : MonoBehaviour
{
[SerializeField] private int nexSceneIndex;
private void Update()
{
if (!Input.GetKeyDown(KeyCode.Space)) return;
MySceneManager.LoadScene(nexSceneIndex, this);
}
}
And have 3 Scenes:
Main: As mentioned contains
the MainCamera
a DirectionalLight
the LoadFirstScene
test: contains
a MoveBall "Sphere"
the LoadNextScene
test2: contains
a MoveBall "Cube"
the LoadNextScene
With the indexes matching the build settings (make sure Main is always at 0 ;) )
I can now switch between test and test2 using the Space key.
If I drag one of the objects meanwhile I can carry it on into the next scene (but only 1 at a time). I can even take it on again back to the first scene in order to have e.g. two sphere objects I can play with ;)

How to resume game after pressing back in menu

Hey I am trying to make a pause menu in my game. When escape is pressed pause game go to menu, but now I want to be able to press back in menu and resume my game. So far I can only pause game and cant press back. Also if i press Play in menu it starts at my tutorial scene and not the current scene. Is there a smart way to do this? Without resetting my game.
`using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UI;
public class MenuScript : MonoBehaviour
{
// Use this for initialization
void Start()
{
}
// Update is called once per frame
void Update()
{
if (Input.GetKey(KeyCode.Escape))
{
if (Time.timeScale == 0)
{
Time.timeScale = 1;
}
else
{
Time.timeScale = 0;
}
SceneManager.LoadScene("Menu");
}
}
}`

I get that this isn't straightforward problem since you seem new to Unity.
You got the idea correctly, changing the time scale will freeze all agents on the scene. HOWEVER, if you load a new scene you'll need to reload the game scene - losing any data you had (and that is not what you want). My advice is creating an overlay element (UI) on the game scene and just show/hide it. There are multiple tutorials online use this as an starting point. Let me know if you require more help.
code sample
// Update is called once per frame
void Update()
{
if (Input.GetKey(KeyCode.Escape))
{
if (Time.timeScale == 0)
{
Time.timeScale = 1;
pauseMenu.gameObject.setActive(true);
}
else
{
Time.timeScale = 0;
pauseMenu.gameObject.setActive(false);
}
}
}
You will need a reference to the pauseMenu game object attached on this script using the Unity editor.

Depending on what you need, this would work as well.
private bool _isPaused;
private void Update(){
if (Input.GetKeyUp(KeyCode.Escape))
{
_isPaused = !_isPaused;
if (_isPaused)
{
//Do Pause Logic here
}
else
{
//Do Unpause Logic Here
}
}
}

Unity - Change character only when animation stopped

i have two objects(the same character, but, in different functions) which i want change the character when animation stop and when it runs triggered by a click. For example, I have the Kick_Player where there is the animation triggered by the click, and when the Kick_Player ends the animation, i want it automatically changes to Player_Stopped. The poses are different each other, 'cause this i need to do these changes.
I tried something with this.MyAnimator.GetCurrentAnimatorStateInfo(0).IsName("My_Animation") but, i got unsuccessful tries. Is there a way to do that ?
public class TapController : MonoBehaviour {
Animator Anim;
public GameObject CharacterToController; //Kick_Player
public GameObject CharacterToBeStopped; //Player_Stopped
void Start(){
Anim = CharacterToController.GetComponent<Animator>();
CharacterToBeStopped.SetActive(false);
}
void Update(){
if(input.GetMouseButtonDown(0)){
if(!CharacterToController.activeSelf){
CharacterToController.SetActive(true);
}
Anim.Play("Kick_Ball");
if(!this.Anim.GetCurrentAnimatorStateInfo(0).IsName("Kick_Ball") {
CharacterToController.SetActive(false);
CharacterToBeStopped.SetActive(true);
}
}
}
I made this code to test, but it doesn't work

Using the IsName function requires that you prefix the base layer name of the animation state before the actual animation state.
The default base name is usually "Base Layer"
if(!this.Anim.GetCurrentAnimatorStateInfo(0).IsName("Base Layer.Kick_Ball")
Note that you have to do that outside your if(input.GetMouseButtonDown(0)){ otherwise that will never get chance to be checked.
I've seen reports of IsName not working for some people so if you do that but still have issues, consider doing it another way.
void Update()
{
if (Input.GetMouseButtonDown(0))
{
if (!CharacterToController.activeSelf)
{
CharacterToController.SetActive(true);
}
Anim.Play("Kick_Ball");
StartCoroutine(PlayAndWaitForAnim(Anim, "Kick_Ball"));
}
}
const string animBaseLayer = "Base Layer";
int animHash = Animator.StringToHash(animBaseLayer + ".Kick_Ball");
public IEnumerator PlayAndWaitForAnim(Animator targetAnim, string stateName)
{
targetAnim.Play(stateName);
//Wait until we enter the current state
while (targetAnim.GetCurrentAnimatorStateInfo(0).fullPathHash != animHash)
{
yield return null;
}
float counter = 0;
float waitTime = targetAnim.GetCurrentAnimatorStateInfo(0).length;
//Now, Wait until the current state is done playing
while (counter < (waitTime))
{
counter += Time.deltaTime;
yield return null;
}
//Done playing. Do something below!
Debug.Log("Done Playing");
CharacterToController.SetActive(false);
CharacterToBeStopped.SetActive(true);
}

Unity, C#: Delay on function not working? Waitforseconds?

I am creating a VR app using Google Cardboard in Unity and I have succeeded in switching from VR to a normal view with this function:
public GameObject[] cardboardObjects;
public GameObject[] monoObjects;
public bool switched = false;
// Turn on or off VR mode
void ActivateVRMode(bool goToVR) {
foreach (GameObject cardboardThing in cardboardObjects) {
cardboardThing.SetActive(goToVR);
}
foreach (GameObject monoThing in monoObjects) {
monoThing.SetActive(!goToVR);
}
Cardboard.SDK.VRModeEnabled = goToVR;
// Tell the game over screen to redisplay itself if necessary
//gameObject.GetComponent<GameController>().RefreshGameOver();
}
I then call this function on a button to switch to mono view:
public void Switch() {
ActivateVRMode(false);
switched = true;
Debug.Log (switched+"No VR!");
}
I then want to have the mono view on a timer, as in once the user switches to non-VR mode it remains in that for only a set amount of time (3 seconds or so) before switching back to VR.
I tried to do this by flipping a boolean and using WaitForSeconds, however the view remains in mono view and nothing happens:
IEnumerator Switchback()
{
yield return new WaitForSeconds(3);
ActivateVRMode(true);
switched = false;
Debug.Log (switched+"VR!");
}
void Update () {
if (switched == true) {
Switchback ();
}
//Debug.Log ("updating");
}
What am I doing wrong here?

You have forgotten to call the Switchback function as a Coroutine
Instead of calling Switchback() you need to call StartCoroutine(Switchback()) in your Update() function.