[C#] Instantiate objects at a random time between a random range.

Unity Engine
1

Hey guys,

I’m having trouble with creating a script in C# that does what the title says, Instantiate objects at a random time between a random range.

I need to spawn spheres at a random time range such as between 1-4 seconds in a random transform range such as X (14, 15).

I was going to do something along the lines of this below in C# and then calling the function(void in C#) when the spheres collide with barriers I put in place outside of the camera. But not sure how to clamp the random time spawn as well as instantiating them in those random.range’s.

function ResetBall()
{
	//Resets position
	transform.position.x = Random.Range(13,-13);
	transform.position.y = Random.Range(14,15);
}

Thanks.

2

A coroutine is a good way to do this:

IEnumerator ResetBall()
{
	while( Application.isPlaying )
	{
		//Resets position
		transform.position.x = Random.Range(13,-13);
		transform.position.y = Random.Range(14,15);


		yield return new WaitForSeconds( Random.Range( 1,4 ) );
	}
}
3

I’m sorry but maybe I’m missing it in the code or I didn’t explain it enough.

I’m trying to spawn a sphere at a random time in a random range for coords. I would then like to call the ResetBall (+ the random time part) function once the sphere collides with my barrier in order to save performance.

So it would be something along the lines of the below code:

void  OnTriggerEnter ( Collider other  ){
	
	if(other.gameObject.tag == "OutOfBounds")
	{
		ResetBall();
	}
}

   void  ResetBall (){

	transform.position.x = Random.Range(13,-13);
	transform.position.y = Random.Range(19,19);

//+ the yield WaitForSeconds part
        }
  • the need to instantiate the sphere, which I can’t remember how to do in C# :S I’ve been using Java a ton but now I’m switching to C#.

So I’d like to use my prefab sphere and then instantiate it, once is goes “OutOfBounds” do the random range respawn and time delay. But not sure how to make that one script? Unless it needs to be 2.

Thanks for the quick response by the way!

4

Ball.cs might look something like:

void  OnTriggerEnter ( Collider other  ){
    if(other.gameObject.tag == "OutOfBounds") {
		StartCoroutine (ResetBall());
    }
}
 
IEnumerator ResetBall (){
    // hide until timer is ready
    gameObject.SetActiveRecursively (false);
    transform.position.x = Random.Range(13,-13);
    transform.position.y = Random.Range(19,19);
    yield return new WaitForSeconds (Random.Range( 1,4 ));
    gameObject.SetActiveRecursively (true);
}

Either your ball is in the scene already and your game play stays in that scene then you don’t need to care about instantiating. Most often you will have for example a variable number of balls. In these cases you might want to have a spawner class in your scene:

public class Spawner {
	public GameObject ballPrefab;
	
	void Start () {
		GameObject ball = Instantiate (ballPrefab) as GameObject;
	}
}
5

Hey kayy,

tried the code out and it wont work.

Error is “Cannot modify a value type return value of `UnityEngine.Transform.position’. Consider storing the value in a temporary variable”.
As you could imagine the error is on the transform.position.x and y lines.

6

that means you have to put the transform in a variable, work on that variable then set the transform to that variable.

So in this case it would be something like:

Vector3 myposition = this.transform.position;
myposition.x =Random.Range(13,-13);
myposition.y =Random.Range(19,19); // wont this always be 19?
this.transform.position=myposition;
7

Tried it and there is an error:
Keyword `this’ is not available in the current context

It’s referring to the variable that I am declaring at the start of the Vector3.

Also I just inputted random numbers, now that I have an instantiate script I don’t need Y.

Thanks!

8

delete it then, what I said is C# maybe you are using unityscript