Vector2.MoveTowards

# [Vector2](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector2.html).MoveTowards

public static [Vector2](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector2.html) **MoveTowards** ([Vector2](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector2.html) **current**, [Vector2](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector2.html) **target**, float **maxDistanceDelta**);

## 描述

将点 `current` 移向 /target/。

这本质上与 [Vector2.Lerp](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector2.Lerp.html) 相同，但是该函数确保距离不超过 `maxDistanceDelta`。 `maxDistanceDelta` 为负值时会将矢量推离 /target/。

```
using UnityEngine;

// 2D MoveTowards example
// Move the sprite to where the mouse is clicked
//
// Set speed to -1.0f and the sprite will move
// away from the mouse click position forever

public class ExampleClass : MonoBehaviour
{
    private float speed = 10.0f;
    private Vector2 target;
    private Vector2 position;
    private Camera cam;

void Start()
    {
        target = new Vector2(0.0f, 0.0f);
        position = gameObject.transform.position;

cam = Camera.main;
    }

void Update()
    {
        float step = speed * Time.deltaTime;

// move sprite towards the target location
        transform.position = Vector2.MoveTowards(transform.position, target, step);
    }

void OnGUI()
    {
        Event currentEvent = Event.current;
        Vector2 mousePos = new Vector2();
        Vector2 point = new Vector2();

// compute where the mouse is in world space
        mousePos.x = currentEvent.mousePosition.x;
        mousePos.y = cam.pixelHeight - currentEvent.mousePosition.y;
        point = cam.ScreenToWorldPoint(new Vector3(mousePos.x, mousePos.y, 0.0f));

if (Input.GetMouseButtonDown(0))
        {
            // set the target to the mouse click location
            target = point;
        }
    }
}
```