一、简单的场景

二、鼠标移向物体、选中、点击、移动、离开。

1、鼠标移向物体

2、鼠标选中物体
首先移向物体

然后选中物体。

3.移动物体

三、下面是程序代码
脚本：ApiOnMouseButton

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

public class ApiOnMouseButton : MonoBehaviour {
public Renderer rend;
public Vector3 targetPos;
public Vector3 lastPos;

bool isdrag=false;//用来判断物体是否被拖拽

void Start () {
rend = GetComponent<Renderer> ();
}

void Update () {

}
//当鼠标移动到物体上
void OnMouseEnter() {
if(!isdrag)
rend.material.color = Color.blue;

}
//当鼠标按下物体
void OnMouseDown(){
if(!isdrag){
rend.material.color = Color.yellow ;
lastPos = Camera.main.ScreenToViewportPoint( Input.mousePosition)-Camera.main.WorldToViewportPoint(transform.position);

}
}
//当鼠标拖拽物体
void OnMouseDrag(){
targetPos = Camera.main.ViewportToWorldPoint( Camera.main.ScreenToViewportPoint(Input.mousePosition)-lastPos);
transform.position = new Vector3 (targetPos.x, targetPos.y, targetPos.z);

isdrag = true;

}
//当鼠标离开物体
void OnMouseExit(){
if(!isdrag)
rend.material.color = Color.white;
}
void OnMouseUp(){
rend.material.color = Color.blue;
isdrag = false;
}
}

将脚本ApiOnMouseButton拖拽到物体身上即可运行~