Main.cs

using UnityEngine;
using System.Collections;

public class Main : MonoBehaviour {
	public GameObject gem;
	public int currentLayer = -1;
	private int lastLayer = -1;
	public Vector3 gridDimensions;
	public Vector3 centerOfGridWorld = new Vector3();
	private Vector3 centerOfGridGame = new Vector3();
	private Vector3 centerIndex;
	private static GameObject[,,] grid;
	private int[] gridDims;

	void Start () {
		centerOfGridGame.x = centerOfGridWorld.x + (Constants.GRID_OFFSET * gridDimensions.x);
		centerOfGridGame.y = centerOfGridWorld.y + (Constants.GRID_OFFSET * gridDimensions.y);
		centerOfGridGame.z = centerOfGridWorld.z + (Constants.GRID_OFFSET * gridDimensions.z);
		gridDims = new int[] {(int) gridDimensions.x, (int) gridDimensions.y, (int) gridDimensions.z};
		//centerIndex = gridDimensions / 2;
		centerIndex = new Vector3(gridDims[0] / 2, gridDims[1] / 2, gridDims[2] / 2);
		grid = new GameObject[gridDims[0], gridDims[1], gridDims[2]];
		FillGrid();
	}
	
	void Update () {
		if (currentLayer != lastLayer)
			ChangeLayer();
	}

	void FillGrid() {
		//Vector3 worldOffset = Vector3.one * Constants.WORLD_OFFSET;
		for (int x = 0; x < gridDims[0]; x++) {
			for (int y = 0; y < gridDims[1]; y++) {
				for (int z = 0; z < gridDims[2]; z++) {
					int index = Random.Range(0, System.Enum.GetValues(typeof(GemDefinition.Gems)).Length - 1);
					Vector3 current = new Vector3(x, y, z);
					Vector3 pos = centerOfGridWorld + (Constants.GRID_OFFSET * (current - centerIndex))/* + worldOffset*/;
					grid[x, y, z] = Instantiate(gem.transform.GetChild(index), pos, Quaternion.AngleAxis(90, Vector3.up)) as GameObject;
				}
			}
		}
	}

	void ChangeLayer() {
		lastLayer = currentLayer;
		for (int x = 0; x < gridDims[0]; x++) {
			for (int y = 0; y < gridDims[1]; y++) {
				for (int z = 0; z < gridDims[2]; z++) {
					grid[x, y, z].gameObject.SetActive(!(currentLayer > -1 && currentLayer != x));
				}
			}
		}
	}
}