【Unity】簡単明快なdrawcall削減の例 ref: http://qiita.com/kuuki_yomenaio/items/eaea133479bb8be96870

LoadText.cs

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

public class LoadText {
    // Resources/text/から指定のテキストファイルを改行区切りで読む
    public List<string> loadTextFile(string textFileName){
        TextAsset textAsset = Resources.Load<TextAsset>("text/" + textFileName);
        string[] strs = textAsset.text.Split ("\n" [0]);
        foreach(string str in strs){
            txtList.Add(str);
        }
        return txtList;
    }
}

map_data.txt

1,1.0,-2.0
1,2.3,-0.8
2,1.4,-1.6
2,1.8,-1.2
2,1.5,-0.6
2,1.0,-0.5
〜

MapCreate.cs

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

public class MapCreate : MonoBehaviour {
    // Inspectorでprefabを紐付け
    public GameObject mapParent;
    public GameObject map1;
    public GameObject map2;

    // Use this for initialization
    void Start () {
        // テキストファイルを読み出す
        LoadText loadText = new LoadText ();
        List<string> loadMapTextList = loadText.loadTextFile ("map_1");

        // 文字列からMapDataを生成
        List<MapData> mapDataList = new List<MapData> ();
        foreach (string str in loadMapTextList) {
            MapData map = new MapData();
            map.parse(str);
            mapDataList.Add(map);
        }

        createMap (mapDataList);
    }

    // MapDataからマスをポチポチ置いていく 
    private void createMap(List<MapData> mapList){
        GameObject obj = null;
        foreach (MapData map in mapList) {
            switch(map.ImgId){
            case 1:
                obj = Instantiate(map1) as GameObject;
                break;
            case 2:
                obj = Instantiate(map2) as GameObject;
                break;
            }
            if(obj != null){
                obj.transform.position = new Vector3(map.X , map.Y , 0);
                obj.transform.parent = mapParent.transform;
                obj = null;
            }
        }
    }
}