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

public class MB_DynamicAddDeleteExample : MonoBehaviour
{
    public GameObject prefab;
    List<GameObject> objsInCombined = new List<GameObject>();
    MB3_MultiMeshBaker mbd;
    GameObject[] objs;

    float GaussianValue()
    {
        float x1, x2, w, y1;

        do
        {
            x1 = 2.0f * Random.Range(0f, 1f) - 1.0f;
            x2 = 2.0f * Random.Range(0f, 1f) - 1.0f;
            w = x1 * x1 + x2 * x2;
        } while (w >= 1.0f);

        w = Mathf.Sqrt((-2.0f * Mathf.Log(w)) / w);
        y1 = x1 * w;
        return y1;
    }

    void Start()
    {
        mbd = GetComponentInChildren<MB3_MultiMeshBaker>();

        // instantiate game objects
        int dim = 10;
        GameObject[] gos = new GameObject[dim * dim];
        for (int i = 0; i < dim; i++)
        {
            for (int j = 0; j < dim; j++)
            {
                GameObject go = (GameObject)Instantiate(prefab);
                gos[i * dim + j] = go.GetComponentInChildren<MeshRenderer>().gameObject;
                float randx = Random.Range(-4f, 4f);
                float randz = Random.Range(-4f, 4f);
                go.transform.position = (new Vector3(3f * i + randx, 0, 3f * j + randz));
                float randrot = Random.Range(0, 360);
                go.transform.rotation = Quaternion.Euler(0, randrot, 0);
                Vector3 randscale = Vector3.one + Vector3.one * GaussianValue() * .15f;
                go.transform.localScale = randscale;
                //put every third object in a list so we can add and delete it later
                if ((i * dim + j) % 3 == 0)
                {
                    objsInCombined.Add(gos[i * dim + j]);
                }
            }
        }

        //add objects to combined mesh
        mbd.ClearMesh();
        if (mbd.AddDeleteGameObjects(gos, null, true))
        {
            mbd.Apply();
        }

        objs = objsInCombined.ToArray();
        //start routine which will periodically add and delete objects
        StartCoroutine(largeNumber());
    }

    IEnumerator largeNumber()
    {
        while (true)
        {
            yield return new WaitForSeconds(1.5f);
            //Delete every third object
            if (mbd.AddDeleteGameObjects(null, objs, true))
            {
                mbd.Apply();
            }

            yield return new WaitForSeconds(1.5f);
            //Add objects back
            if (mbd.AddDeleteGameObjects(objs, null, true))
            {
                mbd.Apply();
            }
        }
    }

    void OnGUI()
    {
        GUILayout.Label("Dynamically instantiates game objects. \nRepeatedly adds and removes some of them\n from the combined mesh.");
    }
}