unity3d物体旋转和移动（PC）端

//新建脚本挂在需要移动的物体上
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PcScaleAndRotate : MonoBehaviour {
public Transform target;
private int MouseWheelSensitivity = 1; //放大倍数的快慢
private int MouseZoomMin = 1; //最小倍数
private int MouseZoomMax = 5; //最大倍数
//默认距离
private float normalDistance = 3;
private Vector3 normalized;**

//拖拽的移动速度
private float xSpeed = 250.0f;
private float ySpeed = 120.0f;

//拖拽的高度限制
private int yMinLimit = -20;
private int yMaxLimit = 80;

//角度
private float x = 0.0f;
private float y = 0.0f;

//记录目标物体的坐标
private Vector3 screenPoint;
private Vector3 offset;

//围绕x旋转30°
private Quaternion rotation = Quaternion.Euler(new Vector3(30f, 0f, 0f));

//目标的3D坐标
private Vector3 CameraTarget;

//打印欧拉角:绕各个轴旋转的角度，顺时针为正方向
public void Awake()
{
    print(transform.eulerAngles.x);
    print(transform.eulerAngles.y);
    print(transform.eulerAngles.z);
}
void Start()
{
    //找到目标飞机的3d坐标
    CameraTarget = target.position;

    //目标飞机的z-3，距离摄像机更近了
    float z = target.transform.position.z - normalDistance;
    //给当前相机给定位，现在的3D坐标乘以30°
    transform.position = rotation * new Vector3(transform.position.x, transform.position.y, z);

    //将视角转向物体
    transform.LookAt(target);

    //记录各个轴偏离的角度
    var angles = transform.eulerAngles;
    x = angles.y;
    y = angles.x;
}
void OnGUI()
{
    GUI.Label(new Rect(10, 10, 300, 30), "左击:旋转；滚轮：缩放；中击：拖拽");
}
void Update()
{
    //如果左击了，旋转
    if (Input.GetMouseButton(0))
    {
        x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
        //y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

        y = ClampAngle(y, yMinLimit, yMaxLimit);

        var rotation = Quaternion.Euler(y, x, 0);
        var position = rotation * new Vector3(0.0f, 0.0f, -normalDistance) + CameraTarget;

        transform.rotation = rotation;
        transform.position = position;

    }
    //滚轮缩放
    else if (Input.GetAxis("Mouse ScrollWheel") != 0)
    {
        //摄像机3d坐标-物体的3d坐标
        normalized = (transform.position - CameraTarget).normalized;

        if (normalDistance >= MouseZoomMin && normalDistance <= MouseZoomMax)
        {
            normalDistance -= Input.GetAxis("Mouse ScrollWheel") * MouseWheelSensitivity;
        }
        if (normalDistance < MouseZoomMin)
        {
            normalDistance = MouseZoomMin;
        }
        if (normalDistance > MouseZoomMax)
        {
            normalDistance = MouseZoomMax;
        }
        //改变摄像机的远近
        transform.position = normalized * normalDistance;
    }
    //案件按下 记录鼠标的
    else if (Input.GetMouseButtonDown(2))
    {
        //将目标物体的坐标转化成平面坐标
        screenPoint = Camera.main.WorldToScreenPoint(target.transform.position);
        //计算鼠标的3维坐标跟物体的3维坐标的差值
        offset = target.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
    }

    //中键拖拽，改变飞机的坐标，每帧调用
    if (Input.GetMouseButton(2))
    {
        //鼠标的平面坐标
        Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
        //鼠标转移的3d空间坐标值
        Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
        //改变鼠标的3D空间坐标
        target.transform.position = curPosition;
    }
    //朝向，每动一帧都要改变朝向
    transform.LookAt(CameraTarget);
}

//控制旋转的角度，如果旋转的角度大于360或者小于360都要加上或者减去对应的角度
static float ClampAngle(float angle, float min, float max)
{
    if (angle < -360)
        angle += 360;
    if (angle > 360)
        angle -= 360;
    return Mathf.Clamp(angle, min, max);
}

}