Unity3D 相机绕对象旋转和调整距离_unity 围绕物体旋转距离保持不变

using UnityEngine;
 
public class MouseFollowRotation : MonoBehaviour
{
    public Transform target;
    public float xSpeed = 200;
    public float ySpeed = 200;
    public float mSpeed = 10;
    public float yMinLimit = -50;
    public float yMaxLimit = 50;
    public float distance = 2;
    public float minDistance = 2;
    public float maxDistance = 30;
 
    //bool needDamping = false;
    public bool needDamping = true;
    float damping = 5.0f;
 
    public float x = 0.0f;
    public float y = 0.0f;
 
    // Use this for initialization
    void Start()
    {
        Vector3 angles = transform.eulerAngles;
        x = angles.y;
        y = angles.x;
    }
 
    // Update is called once per frame
    void LateUpdate()
    {
        if (target)
        {
            //use the light button of mouse to rotate the camera
            if (Input.GetMouseButton(1))
            {
                x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
                y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
 
                y = ClampAngle(y, yMinLimit, yMaxLimit);
            }
            distance -= Input.GetAxis("Mouse ScrollWheel") * mSpeed;
            distance = Mathf.Clamp(distance, minDistance, maxDistance);
            Quaternion rotation = Quaternion.Euler(y, x, 0.0f);
            Vector3 disVector = new Vector3(0.0f, 0.0f, -distance);
            Vector3 position = rotation * disVector + target.position;
            //adjust the camera
            if (needDamping)
            {
                transform.rotation = Quaternion.Lerp(transform.rotation, rotation, Time.deltaTime * damping);
                transform.position = Vector3.Lerp(transform.position, position, Time.deltaTime * damping);
            }
            else
            {
                transform.rotation = rotation;
                transform.position = position;
            }
        }
    }
 
    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);
    }
}