Develop Reference

Sphere not moving in Unity

I'm stuck with this one for quite some time now. I am trying to create spheres via script and update their position based on the position of points. Their position is updating on the Debug.Log() but they are not moving in Game View.
Here is my code:
void createSpheres(int objCount, float xPointsPos, float yPointsPos){
var sphereCreator = GameObject.CreatePrimitive(PrimitiveType.Sphere);
sphereCreator.transform.localScale = new Vector3(0.1f, 0.1f, 0.1f);
sphereCreator.transform.position = new Vector3(xPointsPos, yPointsPos, 0);
sphereCreator.AddComponent<Rigidbody>();
sphereCreator.GetComponent<Rigidbody>().useGravity = false;
sphereCreator.AddComponent<SphereCollider>();
//ADD THE SPHERES TO THE SPHERELIST
sphereList = new List<Sphere>();
for(int loop = 0; loop < objCount-1; loop++){
Sphere temp = new Sphere();
temp.sphereName = "sphere"+sphereNameCount;
temp.sphereObj = sphereCreator;
temp.sphereXPos = xPointsPos;
temp.sphereYPos = yPointsPos;
sphereList.Add(temp);
}
sphereNameCount++;
}
void UpdateSpheres()
{
for(int i = 0; i < sphereList.Count - 1; i++){
sphereList[i].sphereXPos = points[i].position.x;
sphereList[i].sphereYPos = points[i].position.y;
Debug.Log($"{sphereList[i].sphereXPos}" + " -- " + $"{points[i].position.x}");
}
}
public class Sphere{
public string sphereName;
public float sphereXPos;
public float sphereYPos;
public GameObject sphereObj;
}
The createSpheres() method is called inside a loop containing how many points are spawned to match it.
I also tried checking if the ArrayList is empty or not using Debug.Log() and it returned all the Sphere gameObjects that I added.
Any help or hint will be highly appreciated. Thanks!

You do not create a number of spheres according to the code. You create just a single sphere and assign it to all your Sphere instances. To create and move your spheres:
create GameObject object for every object instead of assigning the same object for each Sphere class instance
use .transform.position of the created object, assigned to Sphere class instance to move the corresponding GameObject instance

How do I access a prefab and all of its instantiated clones in c# and unity?

I need a little help again please. I'm currently working on powerups and it's setup so that the powerup affectsthe prefab thats put into its prefab slot, so this is means it is currently only affecting one object (in my case, enemy). When the game starts I spawn about 20 enemies and if i pickup the powerup I want it to affect all those spawned enemies and not only the one that is dragged onto the script, does anyone have a solution or alternate method to do this please?

When instantiate them store them in a list and then iterate through all and update their value
In your case e.g.
// if enemies have a certain Component rather use that type here instead of GameObject
public GameObject enemyPrefab;
// and use the same type here instead of GameObject
private List<GameObject> enemyInstances = new List<GameObject> enemyInstances;
private void Start()
{
for(int i = 0; i < 20; i++)
{
var newEnemy = Instantiate(enemyPrefab);
enemyInstances.Add(newEnemy);
}
}
and then later
public void UpdateEnemies()
{
foreach(var enemy in enemyInstances)
{
// skip already destroyed objects
if(!enemy) continue;
// whatever to be done to the enemies
}
}

To get all game objects to an array you can use the Tag.
Just add an 'Enemy' tag to the prefab and use the code below:
public GameObject[] enemys;
void Start()
{
respawns = GameObject.FindGameObjectsWithTag("Enemy");
}
Full Unity documentation HERE

How to add Script to instantiated object at runtime?

I have a Script in my main Assets folder called BezierWalk.cs
In another script, Spawn, I'm trying to instantiate objects from Prefab Sphere and attach BezierWalk.cs to them.
Spawn script:
public class Spawn : MonoBehaviour
{
public GameObject Sphere;
//string ScriptName = "BezierWalk";
void Start()
{
Vector3 vSpawnPos = transform.position;
for (int i = 0; i < 20; i++)
{
var objectYouCreate = Instantiate(Sphere, vSpawnPos, transform.rotation);
//objectYouCreate.AddComponent<T>("Assets/BezierWalk.cs");
//objectYouCreate.AddComponent(typeof(ScriptName)) as ScriptName;
//objectYouCreate.AddComponent<ScriptName>();
//var myScript = Sphere.AddComponent<BezierWalk.cs>();
vSpawnPos.z += 20;
}
}
You can see commented out attempts...
How I am supposed to do this properly? Thank you.

If you look at how you reference components in unity, the answer should be clear - did you try any of the ones you listed?
Reference: https://docs.unity3d.com/ScriptReference/GameObject.AddComponent.html
The normally used is as it is easy reading
objectYouCreate.AddComponent<ClassName>();
You can use
objectYouCreate.AddComponent(typeof(ClassName));
the .cs is for humans, its your readable version. so you would never need the .cs reference in your code.
note: I mentioned it as ClassName rather than scriptname, as while they are the same in monobehaviors in unity, it isnt the same anywhere else in c# so, the important bit is not the name of the file you made, but the name of the class within it.
Another way is to have prefabs, make a prefab of your object with all the components you need already on it.

If your script lies within certain namespace, you should follow the following format
GameObject.AddComponent(typeof(namespace.className));

assign class objects instead of the actual script class to unity game objects in unity c#

I want to create a game in Unity C# in which the player will add as much as drones he needs as game objects to the game world. Therefore, I made a drone prefab and later in runtime I ask the number of drones the player wants to have (e.x. n numbers) and instantiate the prefab n times.
The script which is attached to the drone prefab is called drone_script.
Therefore, I am having a drone_script class as a general class. This class has an attribute (let's call it subscriber) which should have different unique values for each drone. So, it is created as a null reference in drone_script general class and later in runtime, I will initialize it.
During runtime, I create n (the same numbers as the drone game objects) objects from this class and assign their subscriber attribute different values.
This is how it looks:
some_class
{
for (int i = 0; i < number_of_Drones; ++i)
{
drones_script[i] = new drone_script();
\\ here I am creating n objects of my general drone_script class
drones_script[i].drone_subscriber = a unique value;
\\ here I am assigning to each of the drone objects' drone_subscriber attribute a different value.
drco = new Vector3((float)0, (float)1, (float)0);
drones[i] = Instantiate(Resources.Load("drone"), drco,
Quaternion.Euler(-90, 0, 90)) as GameObject;
\\I instatiate the drone prefab in unity game world here.
}
}
drone_script
{
public ROSBridgeSubscriber drone_subscriber;
void Start() { \\some code }
void FixedUpdate () { \\some code }
}
My problem is when the drone game objects are created in unity, the general class drone_script is attached to them and because of this their subscriber attribute is null. However, I need the drone_script[i] object to be assigned to them as their script, not the general drone_script itself. Because only then each drone game object has its corresponding subscriber attribute value from before even the start function is being called.
Am I thinking correctly?
If yes, how can I do it?

First of all, I suggest you to assign dronePrefab using editor or in Start method of "some_class" because Resources.Load("drone") might be resource consuming, since you load a drone resource "n" times.
Now your specific problem, you don't need to create new instances of "drone_script" because as you mentioned yourself, each drone that you create has his own "drone_script". So basically what we need to do is:
Instantiate drone and save his reference (as GameObject)
Get that drone's "drone_script" (using GetComponent<>(); )
Save that script reference in our array so we can use it later
Adjust some variables of that script now or later in the game
Something like that should work. In code everything should be something like this (didn't test, might be some miss types)
some_class
{
public GameObject dronePrefab;
for (int i = 0; i < number_of_Drones; ++i)
{
// Step 1.
drco = new Vector3((float)0, (float)1, (float)0);
drones[i] = Instantiate(dronePrefab, drco,
Quaternion.Euler(-90, 0, 90)) as GameObject;
// Steps 2 & 3
drones_script[i] = drones[i].GetComponent<drone_script>();
// Step 4
drones_script[i].drone_subscriber = a unique value;
}
}
EDIT:
Just to point it out: drone_script has to be attached to drone prefab

Unity 3D spawning a prefab from a List

I made a script where it loads the prefabs from my Resources/ai folder and loop up to five times and generate a random index number. It successfully loaded my prefabs as GameObjects and does generate random index based on the count of the List.
However, I am having trouble upon spawning my prefab to my scene since Instatiate command does return an error while I'm coding.
I have tried methods to grab the name of the prefab through list[index].name or even list[index].toString() but it wont work. (Note: list stands for a variable of a list index is just an index to grab the game object on the list. This is not the actual code).
How to spawn a loaded GameObject prefab to my scene with a list?
My current code:
public List<GameObject> ai;
public GameObject[] spawn;
int indexAI;
int indexSpawn;
private void Start()
{
var res = Resources.LoadAll<GameObject>("ai/");
foreach (GameObject obj in res)
{
ai.Add(obj);
}
for (int x=0; x<5; x++)
{
indexAI = UnityEngine.Random.Range(0,ai.Count);
indexSpawn = UnityEngine.Random.Range(0, spawn.Length);
string name = ai[indexAI].name;
Debug.Log(name);
//I am currently using this kind of format since this is what I know for now.
Instantiate(name,spawn[indexSpawn].transform.position,spawn[indexSpawn].transform.rotation);
}
The error looks like this
Thanks!

You are attempting to instantiate a string - you need to instantiate the gameobject in your ai list instead.
Instantiate(ai[indexAI] ,spawn[indexSpawn].transform.position, spawn[indexSpawn].transform.rotation);