znjt/Assets/Scripts/Tool/Map.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class Map : MonoBehaviour
{

	public RectTransform ViewPort;  //小地图的视野范围
	public Transform Corner1, Corner2;     //放置在地形两个对角上标识位置的空物体 ，以便获得地形的尺寸
	public GameObject BlipPrefab;//显示玩家位置的预设
	public static Map Current;

	private Vector2 terrainSize;  //地形的大小

	private RectTransform mapRect;  //获取当前地图的位置

	public Map()
	{
		Current = this;
	}

	// Use this for initialization
	void Start()
	{
		terrainSize = new Vector2(
			Corner2.position.x - Corner1.position.x,
			Corner2.position.z - Corner1.position.z);

		mapRect = GetComponent<RectTransform>();
	}
	/// <summary>
	/// 把世界位置转成地图位置的方法
	/// </summary>
	/// <param name="point"></param>
	/// <returns></returns>
	public Vector2 WorldPositionToMap(Vector3 point)
	{
		var pos = point - Corner1.position;    //得到当前位置相对于地形起始角的位置
		var mapPos = new Vector2(
			point.x / terrainSize.x * mapRect.rect.width,
			point.z / terrainSize.y * mapRect.rect.height);   //缩放到能适配地图尺寸的点
		return mapPos;
	}

	// Update is called once per frame
	void Update()
	{
		ViewPort.position = WorldPositionToMap(Camera.main.transform.position);
	}
}