unity中SmoothFollow.js的c#代码

因为unity 2017.1 没有SmoothFollow.js，所以在网上找了替换的代码

// Converted from UnityScript to C# at http://www.M2H.nl/files/js_to_c.php - by Mike Hergaarden

using UnityEngine;
using System.Collections;

// Place the script in the Camera-Control group in the component menu
[AddComponentMenu("Camera-Control/Smooth Follow CSharp")]

public class CameraFollowTarget : MonoBehaviour
{
/*
This camera smoothes out rotation around the y-axis and height.
Horizontal Distance to the target is always fixed.

There are many different ways to smooth the rotation but doing it this way gives you a lot of control over how the camera behaves.

For every of those smoothed values we calculate the wanted value and the current value.
Then we smooth it using the Lerp function.
Then we apply the smoothed values to the transform's position.
*/

// The target we are following
public Transform target;
// The distance in the x-z plane to the target
public float distance = 10.0f;
// the height we want the camera to be above the target
public float height = 5.0f;
// How much we
public float heightDamping = 2.0f;
public float rotationDamping = 3.0f;

void LateUpdate()
{
// Early out if we don't have a target
if (!target)
return;

// Calculate the current rotation angles
float wantedRotationAngle = target.eulerAngles.y;
float wantedHeight = target.position.y + height;
float currentRotationAngle = transform.eulerAngles.y;
float currentHeight = transform.position.y;

// Damp the rotation around the y-axis
currentRotationAngle = Mathf.LerpAngle(currentRotationAngle, wantedRotationAngle, rotationDamping * Time.deltaTime);

// Damp the height
currentHeight = Mathf.Lerp(currentHeight, wantedHeight, heightDamping * Time.deltaTime);

// Convert the angle into a rotation
Quaternion currentRotation = Quaternion.Euler(0, currentRotationAngle, 0);

// Set the position of the camera on the x-z plane to:
// distance meters behind the target
transform.position = target.position;
transform.position -= currentRotation * Vector3.forward * distance;

// Set the height of the camera
transform.position = new Vector3(transform.position.x, currentHeight, transform.position.z);

// Always look at the target
transform.LookAt(target);
}
}