2D Array Rigidbody details storing error - C#

Question

I am building this project, scattering planets across space randomly and I want Gravitation to be implied accurately. What I am doing is this: 1 Instantiating a random number of planets and scattering them randomly. 2 The actual planets in game should be stored in the first column of my Rigidbody Array (Dw code coming soon) 3 The rest of the columns should just be virtual references to these planets, think of it like having the exact same thing, but just not the planet in game. Example : someArray[somenumber,somenumberaswell] In the first column, that is somenumber=0, the actually visible Rigidbodies in game are stored. In the rest of the columns, their properties are stored. Like the second, third fourth and so on...: someArray[1,somenumberaswell]= some rigidbody's mass; Now here is the code, it is rather long so I put in some helpful comments:

  using UnityEngine;
         using System.Collections;
         public class Gravity : MonoBehaviour {
             public GameObject PlanetCore; //yes it HAS a rigidbody :D
             public static int pnum;
             public static Rigidbody[,] myPlanets;
                 public GameObject[,] obj;
             public Vector3[,] centerofmass;
             public int referencer,looper;
             public Transform[,] objT;
             public float[,] distanceBetweenPlanets;
             void Start () 
             {    
                 pnum = Random.Range(10,15); //a random number of planets
                 myPlanets = new Rigidbody[pnum,pnum] ; //they are both set pnum for the reason I proposed
                 obj = new GameObject[pnum,pnum];
                 objT = new Transform[pnum,pnum];
                 centerofmass=new Vector3[pnum,pnum];
                 radtodeg=new float[pnum];
                 Vector3 planetPosition;
                 //Instantiates planets and scatters them randomly :
                 for(looper=0;looper<myPlanets.GetLength(0);looper++){
                     if(1+looper==1){//so this only runs ONCE
                     for(int looper2=0;looper2<myPlanets.GetLength(0);looper2++){
                         planetPosition = new Vector3(Random.Range(-30f,30f),Random.Range(-30f,-30f),Random.Range(-30f,30f));
                         obj[0,looper2] = (GameObject)Instantiate(PlanetCore,planetPosition,Quaternion.Euler((Random.value+1)*360f,(Random.value+1)*360f,(Random.value+1)*360f));
                         }
                     }
                 //Destroys the planet which was being used to duplicate:
                 Destroy(PlanetCore);
                 looper=1;//looper set to 1 because the 0 column is already set
                 //This is where the problems start: Specifically in the first line under the loop header. so probably in every other line in the loop as well.
                 for(referencer=0;referencer<myPlanets.GetLength(0);referencer++){
                     myPlanets[0,referencer]=obj[looper,referencer].rigidbody;
                     myPlanets[0,referencer].mass=(Random.value+1)*4000f;
                     objT[0,referencer]=obj[looper,referencer].transform;
                     centerofmass[0,referencer]=obj[looper,referencer].rigidbody.worldCenterOfMass;
                     if(referencer+1==myPlanets.GetLength(0)){
                         looper++;
                         referencer=0;
                     }
                 }
                 //Just names the planets:     Planet0, Planet1, etc etc...
                     for(int i=0;i<myPlanets.GetLength(0);i++){
                         obj[0,i].name = "Planet"+i;
                     }
             }
         }

Now the error I keep getting right under that for loop header is this: Object reference not set to an instance of an object. And I keep staring at it and it stares at me and I am like WHY?!

Thanks a lot in advance, I know the code is rather long and might not get an answer, but thanks ! :D

Answer 1

Please use Classes to store property values and also generic Dictionaries are very useful if you know the type before hand Just put this code in a script called "Planets".

It should do the same job you are trying to do but with a very much better way. Refer to comments for what i am doing. If any help needed ask me

Hope this helps.

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class Planets : MonoBehaviour {
     // Use a prefab
     public GameObject planetPrefab;
 
     int numberOfPlanets;
     Vector3 randomPosition;
     Vector3 randomRotation;
     Dictionary<GameObject, PlanetProperties> myPlanets;
 
     // Use this for initialization
     void Start ()
     {
         numberOfPlanets = Random.Range (10, 15);
         myPlanets = new Dictionary<GameObject, PlanetProperties> ();
 
         // Keep your start method readable
         createRandomPlanets ();
 
         // Now you have a dictionary of planets with their properties.
         // You can loop through the dictionary and set different properties if you want
         int i = 0;
         foreach(KeyValuePair<GameObject, PlanetProperties> myPlanet in myPlanets)
         {
             i++;
             myPlanet.Key.name = "SomeRandomPlanet"+i;
             myPlanet.Value.mass = 500000f; 
             //etc ..
         }
 
     }
 
     void createRandomPlanets()
     {
         for(int i =0; i<numberOfPlanets; i++)
         {
             randomPosition = new Vector3(Random.Range(-30f,30f),Random.Range(-30f,-30f),Random.Range(-30f,30f));
             randomRotation = new Vector3((Random.value+1)*360f,(Random.value+1)*360f,(Random.value+1)*360f);
             GameObject newPlanet = Instantiate(planetPrefab, randomPosition, Quaternion.Euler(randomRotation) ) as GameObject;
             PlanetProperties newPlanetPorperties = new PlanetProperties();
             newPlanetPorperties.mass = (Random.value+1)*4000f;
             newPlanetPorperties.transform = newPlanet.transform;
             newPlanetPorperties.centerOfMass = newPlanet.rigidbody.worldCenterOfMass;
             newPlanetPorperties.position = newPlanet.transform.position;
             newPlanetPorperties.planetRef = newPlanet;
             // Here i kept a reference to the newly created planet since the dictionaries key is used to just acces the value which is planet properties.
             // so keeeping the reference to planet you can modify its name etc..
             
             myPlanets.Add(newPlanet, newPlanetPorperties);// add this new planet with detils to the dictionary
         }
     }
 }
 
 public class PlanetProperties
 {
     public float mass;
     public Transform transform;
     public Vector3 centerOfMass;
     public Vector3 position;
     public GameObject planetRef;
     // You can add more properties here like name, color, temp etc
 }

2D Array Rigidbody details storing error - C#

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