三维世界中判断鼠标左键是否点击了方块Cube

EventSystem.IsPointerOverGameObject

public bool IsPointerOverGameObject();

public bool IsPointerOverGameObject(int pointerId);

Description:

Is the pointer with the given ID over an EventSystem object?

例子：

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;//调用系统事件
public class MouseExample : MonoBehaviour {
    void Update () 
    {
        // Check if the left mouse button was clicked
        if(Input.GetMouseButtonDown(0))
        {
            // Check if the mouse was clicked over a UI element
            if(EventSystem.current.IsPointerOverGameObject())
                {Debug.Log("Clicked on the UI");
            }
         }
    }
}