OrbControl.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;

public class OrbControl : MonoBehaviour
{
    int currentOrb = 0;
    int maxOrbs = 3;

    public Transform[] spawnPos;

    public GameObject airOrb;
    public GameObject fireOrb;
    public GameObject waterOrb;

    public bool allowOrbit = false; // if set to true then orbiting functionality needs to be added
    public bool overRideCurrentOrb = false; // if set to true then "currentOrb" will not be used

    public List<GameObject> orbs = new List<GameObject>();

    void Start()
    {
        if (maxOrbs < spawnPos.Length)
        {
            maxOrbs = spawnPos.Length;
        }
    }

    void Update()
    {
        if (Input.GetKeyDown ("q") && currentOrb < maxOrbs)
        {
            spawnAirOrb ();
        }

        if (Input.GetKeyDown ("w") && currentOrb < maxOrbs)
        {
            spawnFireOrb ();
        }

        if (Input.GetKeyDown ("e") && currentOrb < maxOrbs)
        {
            spawnWaterOrb ();
        }
    }

    void spawnAirOrb()
    {
        spawnOrb(airOrb, 0);
    }

    void spawnFireOrb()
    {
        spawnOrb(fireOrb, 1);
    }

    void spawnWaterOrb()
    {
        spawnOrb(waterOrb, 2);
    }

    void spawnOrb(GameObject orb, int index)
    {
        if (orb != null)
        {
            if (!overRideCurrentOrb)
            {
                index = currentOrb;
            }

            GameObject oldOrb = GameObject.Find(orb.name + "(Clone)");
            Vector3 position = spawnPos [index].position;
            Quaternion rotation = spawnPos [index].rotation;

            if (orbs.Count == maxOrbs)
            {
                for (int i = 0; i < orbs.Count; i++)
                {
                    if (((!allowOrbit) && (orbs[i].transform.position == position)) ||
                        ((allowOrbit) && (orbs[i] != null)))
                    {
                        oldOrb = orbs[i];
                        orbs.RemoveAt(i);
                        position = oldOrb.transform.position;
                        rotation = oldOrb.transform.rotation;
                        break;
                    }
                }
            }


            if (oldOrb != null)
            {
                bool destroyOrb = (oldOrb.transform.position == position);
                if (allowOrbit)
                {
                    // if orbiting is allowed then set the position and rotation values to the current object
                    position = oldOrb.transform.position;
                    rotation = oldOrb.transform.rotation;
                }
                if (destroyOrb)
                {
                    Destroy(oldOrb);
                }
            }
            GameObject spawnedOrb = (GameObject)Instantiate (orb, position, rotation);
            orbs.Add(spawnedOrb);

            currentOrb++;
            if (currentOrb >= maxOrbs)
            {
                currentOrb = 0;
            }
        }
    }
}