unity PC和移动端 摄像机围绕目标物体transform组件 旋转 缩放（改变相机position）

using UnityEngine;
using System;
using System.Collections;

public class CameraController : MonoBehaviour {
// Text m_debugTip;
public bool canRotation_X = true;
public bool canRotation_Y = true;
public bool canScale = true;
#region Field and Property
/// <summary>
/// Around center.
/// </summary>
public Transform target;

/// <summary>
/// Settings of mouse button, pointer and scrollwheel.
/// </summary>
public MouseSettings mouseSettings = new MouseSettings(0, 10, 10);

/// <summary>
/// Range limit of angle.
/// </summary>
public Range angleRange = new Range(-90, 90);

/// <summary>
/// Range limit of distance.
/// </summary>
public Range distanceRange = new Range(1, 10);

/// <summary>
/// Damper for move and rotate.
/// </summary>
[Range(0, 10)]
public float damper = 5;

/// <summary>
/// Camera current angls.
/// </summary>
public Vector2 CurrentAngles { protected set; get; }

/// <summary>
/// Current distance from camera to target.
/// </summary>
public float CurrentDistance { protected set; get; }

/// <summary>
/// Camera target angls.
/// </summary>
protected Vector2 targetAngles;


/// <summary>
/// Target distance from camera to target.
/// </summary>
protected float targetDistance;
#endregion

#region Protected Method
protected virtual void Start()
{
// m_debugTip = GameObject.Find("Text").GetComponent<Text>();
CurrentAngles = targetAngles = transform.eulerAngles;
CurrentDistance = targetDistance = Vector3.Distance(transform.position, target.position);
}

protected virtual void LateUpdate()
{
#if UNITY_EDITOR
AroundByMouseInput();
#elif UNITY_ANDROID || UNITY_IPHONE

AroundByMobileInput();
#endif

}

//记录上一次手机触摸位置判断用户是在左放大还是缩小手势
private Vector2 oldPosition1;
private Vector2 oldPosition2;

private bool m_IsSingleFinger;
/*
private void ScaleCamera()
{
//计算出当前两点触摸点的位置
var tempPosition1 = Input.GetTouch(0).position;
var tempPosition2 = Input.GetTouch(1).position;
float currentTouchDistance = Vector3.Distance(tempPosition1, tempPosition2);
float lastTouchDistance = Vector3.Distance(oldPosition1, oldPosition2);
//计算上次和这次双指触摸之间的距离差距
//然后去更改摄像机的距离
distance -= ( currentTouchDistance - lastTouchDistance ) * scaleFactor * Time.deltaTime;
//把距离限制住在min和max之间
distance = Mathf.Clamp(distance, minDistance, maxDistance);
//备份上一次触摸点的位置，用于对比
oldPosition1 = tempPosition1;
oldPosition2 = tempPosition2;
}
*/

protected void AroundByMobileInput()
{
if (Input.touchCount == 1)
{

if (Input.touches[0].phase == TouchPhase.Moved)
{
targetAngles.y += Input.GetAxis("Mouse X") * mouseSettings.pointerSensitivity;
targetAngles.x -= Input.GetAxis("Mouse Y") * mouseSettings.pointerSensitivity;

//Range.
targetAngles.x = Mathf.Clamp(targetAngles.x, angleRange.min, angleRange.max);
}
//Mouse pointer.
m_IsSingleFinger = true;
}

//Mouse scrollwheel.
if (canScale)
{
if (Input.touchCount > 1)
{


//计算出当前两点触摸点的位置
if (m_IsSingleFinger)
{
oldPosition1 = Input.GetTouch(0).position;
oldPosition2 = Input.GetTouch(1).position;
}


if (Input.touches[0].phase == TouchPhase.Moved && Input.touches[1].phase == TouchPhase.Moved)
{
var tempPosition1 = Input.GetTouch(0).position;
var tempPosition2 = Input.GetTouch(1).position;


float currentTouchDistance = Vector3.Distance(tempPosition1, tempPosition2);
float lastTouchDistance = Vector3.Distance(oldPosition1, oldPosition2);

//计算上次和这次双指触摸之间的距离差距
//然后去更改摄像机的距离
targetDistance -= ( currentTouchDistance - lastTouchDistance ) * Time.deltaTime * mouseSettings.wheelSensitivity;
// m_debugTip.text = ( currentTouchDistance - lastTouchDistance ).ToString() + " + " + targetDistance.ToString();


//把距离限制住在min和max之间



//备份上一次触摸点的位置，用于对比
oldPosition1 = tempPosition1;
oldPosition2 = tempPosition2;
m_IsSingleFinger = false;
}
}

}




targetDistance = Mathf.Clamp(targetDistance, distanceRange.min, distanceRange.max);

//Lerp.
CurrentAngles = Vector2.Lerp(CurrentAngles, targetAngles, damper * Time.deltaTime);
CurrentDistance = Mathf.Lerp(CurrentDistance, targetDistance, damper * Time.deltaTime);




if (!canRotation_X) targetAngles.y = 0;
if (!canRotation_Y) targetAngles.x = 0;


//Update transform position and rotation.
transform.rotation = Quaternion.Euler(CurrentAngles);

transform.position = target.position - transform.forward * CurrentDistance;
// transform.position = target.position - Vector3.forward * CurrentDistance;

}

/// <summary>
/// Camera around target by mouse input.
/// </summary>
protected void AroundByMouseInput()
{
if (Input.GetMouseButton(mouseSettings.mouseButtonID))
{
//Mouse pointer.
targetAngles.y += Input.GetAxis("Mouse X") * mouseSettings.pointerSensitivity;
targetAngles.x -= Input.GetAxis("Mouse Y") * mouseSettings.pointerSensitivity;

//Range.
targetAngles.x = Mathf.Clamp(targetAngles.x, angleRange.min, angleRange.max);
}

//Mouse scrollwheel.
if (canScale)
{
targetDistance -= Input.GetAxis("Mouse ScrollWheel") * mouseSettings.wheelSensitivity;

}
// m_debugTip.text = Input.GetAxis("Mouse ScrollWheel").ToString() + " + " + targetDistance.ToString();


targetDistance = Mathf.Clamp(targetDistance, distanceRange.min, distanceRange.max);

//Lerp.
CurrentAngles = Vector2.Lerp(CurrentAngles, targetAngles, damper * Time.deltaTime);
CurrentDistance = Mathf.Lerp(CurrentDistance, targetDistance, damper * Time.deltaTime);




if (!canRotation_X) targetAngles.y = 0;
if (!canRotation_Y) targetAngles.x = 0;


//Update transform position and rotation.
transform.rotation = Quaternion.Euler(CurrentAngles);

transform.position = target.position - transform.forward * CurrentDistance;
// transform.position = target.position - Vector3.forward * CurrentDistance;



}
#endregion
}

[Serializable]
public struct MouseSettings
{
/// <summary>
/// ID of mouse button.
/// </summary>
public int mouseButtonID;

/// <summary>
/// Sensitivity of mouse pointer.
/// </summary>
public float pointerSensitivity;

/// <summary>
/// Sensitivity of mouse ScrollWheel.
/// </summary>
public float wheelSensitivity;

/// <summary>
/// Constructor.
/// </summary>
/// <param name="mouseButtonID">ID of mouse button.</param>
/// <param name="pointerSensitivity">Sensitivity of mouse pointer.</param>
/// <param name="wheelSensitivity">Sensitivity of mouse ScrollWheel.</param>
public MouseSettings(int mouseButtonID, float pointerSensitivity, float wheelSensitivity)
{
this.mouseButtonID = mouseButtonID;
this.pointerSensitivity = pointerSensitivity;
this.wheelSensitivity = wheelSensitivity;
}
}

/// <summary>
/// Range form min to max.
/// </summary>
[Serializable]
public struct Range
{
/// <summary>
/// Min value of range.
/// </summary>
public float min;

/// <summary>
/// Max value of range.
/// </summary>
public float max;

/// <summary>
/// Constructor.
/// </summary>
/// <param name="min">Min value of range.</param>
/// <param name="max">Max value of range.</param>
public Range(float min, float max)
{
this.min = min;
this.max = max;
}
}

/// <summary>
/// Rectangle area on plane.
/// </summary>
[Serializable]
public struct PlaneArea
{
/// <summary>
/// Center of area.
/// </summary>
public Transform center;

/// <summary>
/// Width of area.
/// </summary>
public float width;

/// <summary>
/// Length of area.
/// </summary>
public float length;

/// <summary>
/// Constructor.
/// </summary>
/// <param name="center">Center of area.</param>
/// <param name="width">Width of area.</param>
/// <param name="length">Length of area.</param>
public PlaneArea(Transform center, float width, float length)
{
this.center = center;
this.width = width;
this.length = length;
}
}

/// <summary>
/// Target of camera align.
/// </summary>
[Serializable]
public struct AlignTarget
{
/// <summary>
/// Center of align target.
/// </summary>
public Transform center;

/// <summary>
/// Angles of align.
/// </summary>
public Vector2 angles;

/// <summary>
/// Distance from camera to target center.
/// </summary>
public float distance;

/// <summary>
/// Range limit of angle.
/// </summary>
public Range angleRange;

/// <summary>
/// Range limit of distance.
/// </summary>
public Range distanceRange;

/// <summary>
/// Constructor.
/// </summary>
/// <param name="center">Center of align target.</param>
/// <param name="angles">Angles of align.</param>
/// <param name="distance">Distance from camera to target center.</param>
/// <param name="angleRange">Range limit of angle.</param>
/// <param name="distanceRange">Range limit of distance.</param>
public AlignTarget(Transform center, Vector2 angles, float distance, Range angleRange, Range distanceRange)
{
this.center = center;
this.angles = angles;
this.distance = distance;
this.angleRange = angleRange;
this.distanceRange = distanceRange;
}
}