Trying to add a delay to an gameobject spawner [duplicate] - c#

This question already has answers here:
How to make the script wait/sleep in a simple way in unity
(7 answers)
Closed 4 months ago.
I'm a new C# programmer here in the early stages of creating a project in Unity where you play as a microbe that needs to eat blue food pellets to grow and survive. I've got the blue food pellets to spawn randomly across the map but I want to add a delay because too much is spawning at once. This is what I've attempted to do so far. Any help would be appreciated!
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Threading.Tasks;
public class Spawner : MonoBehaviour
{
public GameObject food;
public async void Wait(float duration)
{
Vector3 randomSpawnPosition = new Vector3(Random.Range(-50, 50), 1, Random.Range(-50, 50));
Instantiate(food, randomSpawnPosition, Quaternion.identity);
await Task.Delay((int)duration * 1000);
}
// Update is called once per frame
void Update()
{
async void Wait(float duration);
}
}
What I've tried:
Putting the delay function in the update function. The program just gets confused and thinks I'm trying to call the function.
Calling the function after combining all my code into the one function, the program rejects this.

Like the default code snippet says, Update runs every frame. Using Task.Delay to delay events would still spawn objects with the same frequency, they would only start spawning delayed.
The typical way to do this in Unity is to use a coroutine.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Spawner : MonoBehaviour
{
[SerializeField] GameObject food;
protected void OnEnable()
{
StartCoroutine(SpawnFoodRoutine());
}
IEnumerator SpawnFoodRoutine()
{
while(enabled)
{
SpawnFood();
var waitTime = Random.Range(1f, 5f);
yield return new WaitForSeconds(waitTime);
}
}
void SpawnFood()
{
Vector3 randomSpawnPosition = new Vector3(
Random.Range(-50f, 50f),
1f,
Random.Range(-50f, 50f));
Instantiate(food, randomSpawnPosition, Quaternion.identity);
}
}

I have made this prefab called “pellet”, then I have created a new gameObject called “SpawnManager” and, finally, added this script to SpawnManager:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SpawnPellet : MonoBehaviour
{
public GameObject prefab;
public bool canSpawnNewPellet = true;
public float delay;
void Update(){
if(canSpawnNewPellet){
Invoke("SpawnNewPellet", delay);
canSpawnNewPellet = false;
}
}
void SpawnNewPellet()
{
GameObject instance = Instantiate(prefab);
instance.transform.position = new Vector3(Random.Range(0,10), Random.Range(0,10), 0);
canSpawnNewPellet = true;
}
}
The I have dragged and dropped/edited values on the fields in the inspector (Prefab, canSpawnNewPellet and Delay). Those are public fields inside the script, so you can populate them drag and dropping directly from your assets folder.
Hit play and you have a new spawn every X seconds where X is the value of delay in seconds.
Screenshot of the game executing after 21 seconds.
What does it do?
Every frame it evaluates if can spawn a new pellet (bool canSpawnNewPellet). If it can, then it starts an invocation of another method with X seconds (and mark the bool as false since we don’t want to call more invocations during de instantiation of our first sample).
For more references: https://docs.unity3d.com/ScriptReference/MonoBehaviour.Invoke.html
Edited: typo.

Related

Unity, why so many prefabs are getting generated?

The code is here:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SpawnManager : MonoBehaviour
{
public GameObject[] animalprefabs;
public float spawninterval = 2.5f;
public float spawnDelay = 2.0f;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
InvokeRepeating("spawnRandomAnimal",spawnDelay, spawninterval);
}
void spawnRandomAnimal()
{
int animalIndex = Random.Range(0, animalprefabs.Length);
int SpawnIndex = 20;
Vector3 spawnPosition = new Vector3(Random.Range(-SpawnIndex, SpawnIndex), 0, 25);
Instantiate(animalprefabs[animalIndex], spawnPosition ,animalprefabs[animalIndex].transform.rotation);
}
}
I want to instantiate the prefab after certain time interval randomly but somehow tonnes of prefabs are getting generated .I want one prefab to be instantiated at a random place after the time interval ... Someone plzzzz help
You are re-calling invokeRepeating every single time Update() is called. Everytime it gets called it adds another task to repeat.
Move it to start to fix your issue.
void Start()
{
InvokeRepeating("spawnRandomAnimal",spawnDelay, spawninterval);
}
you are using invokerepeating() function in update(). that's why too many prefabs are generated. remove invokerepeating() from update() and try it in start() or onenable().

Unity c# - unable to Spawn Prefabs on a NavMesh

I am trying to make a zombie wave game and current have a Prefab for my enemies. If I have the prefab be in the scene when I hit run, they are attached to the NavMesh and track the player perfectly. I want to achieve this but with the enemy being spawned from an empty GameObject so I can get the waves spawning in. I have achieved them Spawning but they have the error,
"SetDestination" can only be called on an active agent that has been placed on a NavMesh.
UnityEngine.AI.NavMeshAgent:SetDestination(Vector3)
EnemyAI:Update() (at Assets/Scripts/EnemyAI.cs:25)
Here is my EnemyAI Script
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;
public class EnemyAI : MonoBehaviour
{
public float lookRadius = 10f;
Transform target;
NavMeshAgent agent;
public GameObject Player;
void Start()
{
agent = GetComponent<NavMeshAgent>();
}
// Update is called once per frame
void Update()
{
float distance = Vector3.Distance(Player.transform.position, transform.position);
if (distance <= lookRadius)
{
agent.SetDestination(Player.transform.position);
}
}
}
And my spawning script, which is attached to an empty game object,
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Spawning : MonoBehaviour
{
public GameObject prefab;
public int CountofCubes;
private IEnumerator coroutine;
public float spawnRate;
IEnumerator Start()
{
while (true)
{
for (int i = 0; i < CountofCubes; i++)
{
Instantiate(prefab, new Vector3(Random.Range(-25.0f, 25.0f), 0.5f, Random.Range(-25.0f, 25.0f)), Quaternion.identity);
}
yield return new WaitForSeconds(spawnRate);
}
}
}
Any help would be great thanks!
I had the same issue and I don't have an explanation but only a workaround:
In the Start fucntion, I added:
navAgent = GetComponent<NavMeshAgent>();
navAgent.enabled = false;
// Invoke is used as a workaround for enabling NavMeshAgent on NavMeshSurface
Invoke("EnableNavMeshAgent", 0.025f);
And the EnableNavMeshAgent function is just :
private void EnableNavMeshAgent ()
{
navAgent.enabled = true;
}
If I set the invoke delay to a value less than 0.025 second the error keep going but for 0.025 I only have it twice and the behaviour is the one I wanted after that.
Some reasons this might happen:
The agent is not on level with any navmesh i.e. can be too far above or below. You want it to be "close to the NavMesh surface". Use raycasting on the floor to position the agent or add a rigidbody and drop it from above the floor. After you do this you might need to disable and enable the agent.
Moving the transform yourself rather than using Wrap function. There's property where you can check if the simulated and actual position are in sync.
Corrupted navmesh so you might need to re-bake it.
It is essentially trying to tell you your agent is not on the mesh so it cannot find a path. Try playing with where you're placing the agent.
I kind of remember running into a similar problem a while back and problem was I forgot to bake the NavMesh in Window > AI > Navigation. Just in case.

Still pausing/resuming and start a new game is not working good. Can'r figure what should I do?

First a screenshot of my Hierarchy :
Everything is inside a one scene name The :
The game start when Main Game is disabled. Inside Main Game sit all the game objects. The Main Menu and Game Manager are enabled.
When running the game first time, When the game start there is short animation of the player for 5 seconds. The player start from some rotating degrees on Z. Z = 50 when x and y both are 0. Then the player is rotating slowly over the Z to 0.
It's like the player is sleeping and awake up.
I'm using post processing stack by unity.
And here is the first problem. While the player is rotating on the Z and post processing effect is working if I press the Escape key it will bring me back to the Main Menu but then if I press the Escape key again it will start the game over again from the begin.
But if I'm waiting in my game for the player to finish rotating on the Z and the post processing effect is finished and then pressing on Escape it will bring the main menu and second time will resume the game from the same point.
I can't figure out why when the player is rotating and the post process is working the escape key make it start the game over again from the being ?
This is a screenshot of the game when start and after finish the rotating and the process stack :
Another problem I noticed now. After the game start using the post process and the player rotating finished if I press Escape it will go to main menu and escape again will be back to the game but for example in the second screenshot the conversation is not continue. It will return to the same point in the game but things not seems to continue like the conversation.
On the Back to main menu object I have a script attached to it :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class BackToMainMenu : MonoBehaviour
{
private bool _isInMainMenu = false;
public GameObject mainGame;
public GameObject mainMenu;
void Update()
{
if (Input.GetKeyDown(KeyCode.Escape))
{
if (!_isInMainMenu)
{
// -- Code to freeze the game
mainGame.SetActive(false);
mainMenu.SetActive(true);
}
else
{
// -- Code to unfreeze the game
mainGame.SetActive(true);
mainMenu.SetActive(false);
}
_isInMainMenu = !_isInMainMenu;
}
}
}
On the Main Menu object under Main Menu I have attached this script :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class MainMenu : MonoBehaviour
{
public GameObject mainGame;
public GameObject mainMenu;
public void PlayGame()
{
mainGame.SetActive(true);
mainMenu.SetActive(false);
}
public void QuitGame()
{
Application.Quit();
}
}
On the PLAY button I'm using this script method PlayGame from the MainMenu script.
In the Main Game object on the Player object attached to thew Player I have some scripts the controller :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
public float speed = 10.0f;
// Update is called once per frame
void Update()
{
float translatioin = Input.GetAxis("Vertical") * speed;
float straffe = Input.GetAxis("Horizontal") * speed;
translatioin *= Time.deltaTime;
straffe *= Time.deltaTime;
transform.Translate(straffe, 0, translatioin);
}
}
Player Lock Manager :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerLockManager : MonoBehaviour
{
public PlayerCameraMouseLook playerCameraMouseLook;
public PlayerController playerController;
// Start is called before the first frame update
public void PlayerLockState(bool LockPlayer, bool LockPlayerCamera)
{
if (LockPlayer == true)
{
playerController.enabled = false;
}
else
{
playerController.enabled = true;
}
if (LockPlayerCamera == true)
{
playerCameraMouseLook.enabled = false;
}
else
{
playerCameraMouseLook.enabled = true;
}
}
}
And Mouse Lock State :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class MouseLockState : MonoBehaviour
{
public bool lockState = true;
private void Start()
{
LockState(lockState);
}
private void Update()
{
}
public void LockState(bool lockState)
{
if (lockState == false)
{
Cursor.visible = true;
Cursor.lockState = CursorLockMode.None;
}
else
{
Cursor.visible = false;
Cursor.lockState = CursorLockMode.Locked;
}
}
}
Under the Player as child I have the Player Camera object and attached to the Player Camera also some scripts :
Player Camera Mouse Look :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerCameraMouseLook : MonoBehaviour
{
public float sensitivity = 5.0f;
public float smoothing = 2.0f;
private GameObject player;
private Vector2 mouseLook;
private Vector2 smoothV;
// Use this for initialization
void Start()
{
player = this.transform.parent.gameObject;
}
// Update is called once per frame
void Update()
{
var md = new Vector2(Input.GetAxisRaw("Mouse X"), Input.GetAxisRaw("Mouse Y"));
md = Vector2.Scale(md, new Vector2(sensitivity * smoothing, sensitivity * smoothing));
smoothV.x = Mathf.Lerp(smoothV.x, md.x, 1f / smoothing);
smoothV.y = Mathf.Lerp(smoothV.y, md.y, 1f / smoothing);
mouseLook += smoothV;
mouseLook.y = Mathf.Clamp(mouseLook.y, -90f, 90f);
transform.localRotation = Quaternion.AngleAxis(-mouseLook.y, Vector3.right);
player.transform.localRotation = Quaternion.AngleAxis(mouseLook.x, Vector3.up);
}
}
And Depth Of Field script :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.PostProcessing;
public class DepthOfField : MonoBehaviour
{
public GameObject player;
public PostProcessingProfile postProcessingProfile;
public bool dephOfFieldFinished = false;
public PlayerLockManager playerLockManager;
private Animator playerAnimator;
private float clipLength;
// Start is called before the first frame update
void Start()
{
playerAnimator = player.GetComponent<Animator>();
AnimationClip[] clips = playerAnimator.runtimeAnimatorController.animationClips;
foreach (AnimationClip clip in clips)
{
clipLength = clip.length;
}
var depthOfField = postProcessingProfile.depthOfField.settings;
depthOfField.focalLength = 300;
StartCoroutine(changeValueOverTime(depthOfField.focalLength, 1, clipLength));
postProcessingProfile.depthOfField.settings = depthOfField;
}
IEnumerator changeValueOverTime(float fromVal, float toVal, float duration)
{
playerLockManager.PlayerLockState(true, true);
float counter = 0f;
while (counter < duration)
{
var dof = postProcessingProfile.depthOfField.settings;
if (Time.timeScale == 0)
counter += Time.unscaledDeltaTime;
else
counter += Time.deltaTime;
float val = Mathf.Lerp(fromVal, toVal, counter / duration);
dof.focalLength = val;
postProcessingProfile.depthOfField.settings = dof;
yield return null;
}
playerAnimator.enabled = false;
dephOfFieldFinished = true;
}
}
I have under Main Game also a object name Openning Scene and attached to it :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class OpeningCutscene : MonoBehaviour
{
public NaviConversations naviConversation;
public DepthOfField dephOfField;
// Update is called once per frame
void Update()
{
if (dephOfField.dephOfFieldFinished == true)
{
naviConversation.PlayNaviConversation(0);
dephOfField.dephOfFieldFinished = false;
}
}
}
It's a bit long but everything is connected.
The game start with the main menu.
When clicking the PLAY button a new game start.
When a new game start the script Depth Of Field is in action using the post processing. Also I'm locking the player so the player will not be able to move either the mouse or the player it self.
When the depth of field script finished his work a conversation between Navi and the Player start. When a conversation is in action the player can move the mouse 360 degrees but cant move the player to any direction.
When the conversation ended the player can also move to any direction.
Problems :
When start a new game while the depth of field script is in work pressing escape will bring the main menu but pressing escape again will not resume the depth of field script but will start it all over again.
When waiting the conversation to end if not pressing escape until the conversation ended then when moving around and pressing escape it will bring the main menu and again will resume the game from the same point.
The problems is when the game is doing something like the depth of field it will start the game over again instead resuming or when in conversation in the middle the conversation will never continue.
The ides with the escape key is once to get to main menu and second to resume the game.
The PLAY button is what should only start a new game and not the escape key.
It's a bit long but everything is connected.
I can't see which objects you hooked up to mainGame and mainMenu in BackToMainMenu from your hierarchy, so I have some conjecture in here.
Sounds like you want Escape key to pause, and unpause, as well as bring up a menu, you want Play button in the menu to restart your game.
However, in both MainMenu and BackToMainMenu you use the same code:
mainGame.SetActive(true);
mainMenu.SetActive(false);
This just turns the objects on and off in the hierarchy. This means the first time you do one of these things, all objects turned on under the gameobject referenced by mainGame will run their Awake and Start methods, but not the second time. Also depending which objects are active (like I said I can't fully see what component is on what object and which objects are referenced by which serialized field) you might be able to introduce a state error on BackToMainMenu._isInMainMenu because that field isn't changed when you hit play. Here is a fantastic image showing execution timeline in Unity:
Monobehavior Timeline
In summary:
The second time you run the game DepthOfField won't call Start a second time. Instead try OnEnable.
The conversation and game logic is not shown in your post, but likely it also is initializing in Start and won't run a second time.
A bit of trickiness around Coroutines is likely to blame here. When DepthOfField starts it also starts a coroutine. That coroutine keeps going even if you set the gameobject inactive. So you run the game once, that coroutine starts, you turn the object off when you hit escape, the coroutine finishes, you hit play again, but DepthOfField.dephOfFieldFinished == true and your playerAnimator is disabled and won't enable again.
Also 5. This kind of behavior can be tricky and is usually dependent on what else you have going on in your scene. Since you have one scene with everything at once, you need to watch out for putting stuff in Awake and Start since this will only run once. Instead you can try a number of things, my favorite is usually to set up a singleton or static class that works as a state machine for the whole scene. It will call custom Initialize functions in your behaviors instead of using Awake and Start.
Keep references to your coroutines by doing things like:
private Coroutine depthOfFieldRoutineRef;
private OnEnable()
{
if (depthOfFieldRoutineRef != null)
{
StopCoroutine(depthOfFieldRoutineRef);
}
depthOfFieldRoutineRef =
StartCoroutine(changeValueOverTime
(depthOfField.focalLength, 1, clipLength));
// Don't forget to set depthOfFieldRoutineRef to null again at the end of routine!
}
For simple pausing behavior you can also try setting Time.timescale = 0; and back to 1 when you want play to resume.
Less a question than a set of problems, hopefully this set of solutions helps!
Tutorial on Awake and Start
Docs on Coroutines
Docs on Time.timescale

How to spawn prefabs within a certain period of time in Unity?

I am trying to create a ball hitting game in the baseball format. I create a ball as a prefab. I want to push the ball to the main scene within a certain period of time.
For example; when the first ball is in the scene, the second ball will spawn after 5-6 seconds, then the third, fourth etc. I am the beginner level of Unity and I am not good at C#. I am not sure whether I am using the true functions such as Instantiate. Here is my script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Ball : MonoBehaviour {
public float RotateSpeed = 45; //The ball rotates around its own axis
public float BallSpeed = 0.2f;
public GameObject[] prefab;
public Rigidbody2D rb2D;
void Start() {
rb2D = GetComponent<Rigidbody2D>(); //Get component attached to gameobject
Spawn ();
}
void FixedUpdate() {
rb2D.MoveRotation(rb2D.rotation + RotateSpeed * Time.fixedDeltaTime); //The ball rotates around its own axis
rb2D.AddForce(Vector2.left * BallSpeed);
InvokeRepeating("Spawn", 2.0f, 2.0f);
}
public void Spawn ()
{
int prefab_num = Random.Range(0,3);
Instantiate(prefab[prefab_num]);
}
}
After I apply this script, the result is not what I want.
Add InvokeRepeating("Spawn", 2.0f, 2.0f); to the Start not the FixedUpdate.
InvokeRepeating invokes the method methodName in time seconds, then repeatedly every repeatRate seconds.
You can check the documentation here.
Use Coroutines
private IEnumerator SpawnBall() {
while(true) {
Instantiate(baseball);
yield return new WaitForSeconds(5);
}
}
Which can then be started with StartCoroutine() and terminated in one of three ways:
internally by breaking out of the while loop with break (the function would then have no more lines to execute and exit)
internally by yield break
externally by calling StopCoroutine() on a reference to the coroutine
Alternative to the other answers: Just use a countdown. This sometimes gives you more control
// Set your offset here (in seconds)
float timeoutDuration = 2;
float timeout = 2;
void Update()
{
if(timeout > 0)
{
// Reduces the timeout by the time passed since the last frame
timeout -= Time.deltaTime;
// return to not execute any code after that
return;
}
// this is reached when timeout gets <= 0
// Spawn object once
Spawn();
// Reset timer
timeout = timeoutDuration;
}
I updated my script by considering your feedbacks and it works like a charm. Thanks to all!
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using System.Threading;
public class Ball : MonoBehaviour {
public float RotateSpeed = 45; //The ball rotates around its own axis
public float BallSpeed = 0.2f;
public GameObject BaseBall;
public Transform BallLocation;
public Rigidbody2D Ball2D;
void Start() {
Ball2D = GetComponent<Rigidbody2D>(); //Get component attached to gameobject
InvokeRepeating("Spawn", 5.0f, 150f);
}
void FixedUpdate() {
Ball2D.MoveRotation(Ball2D.rotation + RotateSpeed * Time.fixedDeltaTime); //The ball rotates around its own axis
Ball2D.AddForce(Vector2.left * BallSpeed);
}
public void Spawn ()
{
Instantiate (BaseBall, BallLocation.position, BallLocation.rotation);
}
}

C# Timer will not stop on trigger enter

I have a beautifully simple script that displays a timer on Unity 5 UI. At a finish line the racer enters a trigger and the timer should stop. It doesn't. I get no errors it just keeps running like Forrest Gump! I plan to post timer results to a leaderboard if I could stop the timer. Here is my timer script:
using UnityEngine;
using UnityEngine.UI;
using System.Collections;
public class Timer : MonoBehaviour
{
public Text timerText;
private float startTime;
private bool finished = false;
// Use this for initialization
void Start () {
startTime = Time.time;
}
// Update is called once per frame
void Update () {
if(finished)
return;
float t = Time.time - startTime;
string minutes = ((int) t / 60).ToString();
string seconds = (t % 60).ToString("f2");
timerText.text = minutes + ":" + seconds;
}
public void finish()
{
finished = true;
timerText.color = Color.yellow;
}
}
On a triggered cube I haved placed the following script:
using UnityEngine;
using System.Collections;
public class WinBox : MonoBehaviour
{
private void onTriggerEnter(Collider other)
{
GameObject.Find("Green").SendMessage("Finish");
}
}
I've changed collision detection to continuous on the rigidbody to my it more sensitive with no luck. Made the cube thicker. Nope, it just keeps on ticking. The vehicle "Green" is in a indexed container/empty game object. It is a networked multiplayer game, so it should probably be rewritten to find the game object with the tag, player. Or somehow the first tagged game object to enter the trigger. I think the problem is 'Send Message' I've never worked with that. The text color change also didn't work, but that needs to be changed to enable confetti particles when the timer stops. Any assist would be greatly appreciated.
There are few problems in your code:
1.Your timer won't stop because the trigger callback function is not being called. The trigger callback function is not being called because onTriggerEnter is supposed to be OnTriggerEnter with the O capitalized.
When you fix this, make sure that the collider has IsTrigger property checked/enabled too.
2.Another problem is this line: GameObject.Find("Green").SendMessage("Finish");
You are calling a function called Finish but the actual name of your function is finish from the Timer class.
Finally, instead of doing GameObject.Find("Green"); in the OnTriggerEnter function, why not cache it in the Start function then re-use it? GameObject.Find is very expensive and doing it many times will slow down your game.
public class WinBox : MonoBehaviour
{
GameObject green;
void Start()
{
green = GameObject.Find("Green");
}
private void OnTriggerEnter(Collider other)
{
green.SendMessage("finish");
}
}

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