3D攝像頭

using UnityEngine;
using System.Collections;

public class SimpleFreeCamera : MonoBehaviour
{
private Transform CameraTr;
public Transform ParentTr;
private Camera Camera;

//Y軸最大旋轉角度
public float MaxY = 90f;
public float MinY = 0f;

//縮放變量;
public float distance = 10f;
public float MinDistance = 2f;
public float MaxDistance = 100f;

public float speed = 5f;

//地面平面
private Plane defaultPlane;
//移動變量;
private Vector3 m_mouseMovePos = Vector3.zero;
private Vector3 LastViewTargetPoint;
private bool IsMove = false;

void Awake()
{
    Camera = GetComponent<Camera>();
    CameraTr = this.transform;
    ParentTr = ParentTr==null?new GameObject("SimpleFreeCamera").transform: ParentTr;
    CameraTr.SetParent(ParentTr);
    transform.LookAt(ParentTr);
    Init();
}
void Init()
{
    CameraTr.transform.localPosition = new Vector3(0, 0, -distance);
    CameraTr.transform.localRotation = Quaternion.identity;
}
void Update()
{
    if (Input.GetMouseButton(1))//鼠標右鍵旋轉
    {
        Rotate(Input.GetAxis("Mouse Y"), Input.GetAxis("Mouse X"));
        LastViewTargetPoint = ParentTr.localPosition;
        SetPanle(LastViewTargetPoint);
    }

    if (Input.GetAxis("Mouse ScrollWheel") != 0) //鼠標中鍵滾輪場景縮放;
    {
        Scale(Input.GetAxis("Mouse ScrollWheel"));
        LastViewTargetPoint = ParentTr.localPosition;
        SetPanle(LastViewTargetPoint);
    }
    //按住鼠標中鍵場景移動;
    if (Input.GetMouseButtonDown(2))//按下鼠標中鍵 記錄移動起點 開啓移動操作
    {
        IsMove = true;
        LastViewTargetPoint = ParentTr.localPosition;
        SetPanle(LastViewTargetPoint);
        m_mouseMovePos = GetMouse3DPosition();
    }
    else if (Input.GetMouseButton(2)) //按住鼠標中鍵 根據位移移動
    {
        if (IsMove)
        {
            ParentTr.localPosition = Vector3.Lerp(ParentTr.localPosition, LastViewTargetPoint - GetMouse3DPosition() + m_mouseMovePos, 0.5f);
            LastViewTargetPoint = ParentTr.localPosition;
        }
    }
    else if (Input.GetMouseButtonUp(2))//放開鼠標中鍵 結束移動操作 
    {
        IsMove = false;
        SetPanle(LastViewTargetPoint);
    }
}
private Vector3 GetMouse3DPosition()
{
    Ray ray = Camera.ScreenPointToRay(Input.mousePosition);
    float enter;
    defaultPlane.Raycast(ray, out enter);
    return ray.GetPoint(enter);

}
/// <summary>
/// 旋轉目標
/// </summary>
/// <param name="dy"></param>
/// <param name="dx"></param>
private void Rotate(float dy, float dx)
{
    float deltX = ParentTr.localRotation.eulerAngles.y;
    float deltY = ParentTr.localRotation.eulerAngles.x;

    deltX += dx * speed;
    deltY -= dy * speed;
    deltX = ClampAngle(deltX, -360, 360);
    deltY = ClampAngle(deltY, MinY, MaxY);
    ParentTr.rotation = Quaternion.Euler(deltY, deltX, 0);
}

private void Scale(float s)
{
    if (Mathf.Abs(transform.localPosition.z) < MinDistance)
        transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, -MinDistance);
    if (Mathf.Abs(transform.localPosition.z) > MaxDistance)
        transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, -MaxDistance);
    float deltD = s * 10f;
    transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, transform.localPosition.z + deltD);
}

private float ClampAngle(float angle, float minAngle, float maxAgnle)
{
    if (angle <= -360)
        angle += 360;
    if (angle >= 360)
        angle -= 360;
    return Mathf.Clamp(angle, minAngle, maxAgnle);
}
/// <summary>
/// 設置平面
/// </summary>
/// <param name="_v3"></param>
private void SetPanle(Vector3 _v3)
{
    defaultPlane.SetNormalAndPosition(-transform.forward, _v3);
}

}