using UnityEngine;
using System.Collections;

public class PrefabPainter : MonoBehaviour {

    public int spawnedPrefabs;
    public int amountOfPrefabs;

    private int toSpawn;
    private int prefabsSpawned;

    public bool spawnedAll;

    public float minimumHeight;
    public float maximumHeight;

    private float randomHeight;
    private float randomPositionX;
    private float randomPositionZ;
    private float randomRotationY;

    private Quaternion randomRotation;

    public GameObject point1;
    public GameObject point2;
    public GameObject prefabToSpawn;

    private GameObject currentSpawnedObject;

    public GameObject[] prefabs;

    void Start () {

        spawnedAll = false;
        prefabs = new GameObject[amountOfPrefabs];
        SpawnPrefabs (amountOfPrefabs);

        point1.GetComponent<MeshRenderer> ().enabled = false;
        point2.GetComponent<MeshRenderer> ().enabled = false;
        gameObject.GetComponent<MeshRenderer> ().enabled = false;
    }

    void Update () {

        if (spawnedAll == true) {
            if (spawnedPrefabs < prefabs.Length) {
                toSpawn = prefabs.Length - spawnedPrefabs;
                Debug.Log ("Needs to Spawn " + toSpawn + " Prefabs!");
                SpawnPrefabs (toSpawn);
                spawnedAll = false;
            }
        }
    }

    void SpawnPrefabs (int amountToSpawn) {

        if (prefabsSpawned < amountToSpawn) {
            for (int i = 0; i < amountToSpawn; i++) {

                randomPositionX = Random.Range (point1.transform.position.x - 1, point2.transform.position.x);
                randomPositionZ = Random.Range (point1.transform.position.z - 1, point2.transform.position.z);

                randomRotationY = Random.Range (0, 360);
                randomRotation = Quaternion.Euler (0, randomRotationY, 0);

                randomHeight = Random.Range (minimumHeight, maximumHeight);

                currentSpawnedObject = (GameObject)Instantiate (prefabToSpawn);

                currentSpawnedObject.transform.rotation = randomRotation;
                currentSpawnedObject.transform.position = new Vector3 (randomPositionX, transform.position.y + prefabToSpawn.transform.localScale.y, randomPositionZ);
                currentSpawnedObject.transform.localScale = new Vector3 (currentSpawnedObject.transform.localScale.x, randomHeight, currentSpawnedObject.transform.localScale.z);

                if (currentSpawnedObject.tag == "corn")
                    currentSpawnedObject.GetComponent<Corn> ().spawnedBy = gameObject;

                for (int k = 0; k < prefabs.Length; k++) {
                    if (prefabs[k] == null) {
                        prefabs[k] = currentSpawnedObject;
                        break;
                    }
                }
                prefabsSpawned += 1;
                spawnedPrefabs += 1;

                Debug.Log ("Amount To Spawn is " + amountToSpawn + ", i is " + i);
                if (i == amountToSpawn - 1) {
                    Debug.Log ("Spawned All");
                    spawnedAll = true;
                }
            }
        }
    }
}

using UnityEngine;
using System.Collections;

public class Corn : MonoBehaviour {

    public GameObject spawnedBy;

    void OnTriggerStay (Collider col) {

        if (col.gameObject.tag == "corn") {

            spawnedBy.GetComponent<PrefabPainter> ().spawnedPrefabs -= 1;
            Destroy (this.gameObject);
        }
    }
}