Vector3.Lerp

# [Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html).Lerp

public static [Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **Lerp** ([Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **a**, [Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **b**, float **t**);

## 参数

| a | 起始值，当 t = 0 时返回。        |
| --- | ---------------------------------- |
| b | 结束值，当 t = 1 时返回。        |
| t | 用于在 a 和 b 之间进行插值的值。 |

## 返回

**Vector3** 插值，等于 a + (b - a) * t。

## 描述

在两个点之间进行线性插值。

使用插值 `t` 在点 `a` 和 `b` 之间进行插值。参数 `t` 限制在范围 [0, 1] 内。这最常用于查找占两个终端之间距离特定百分比的点（例如，以便在这些点之间逐步移动对象）。

返回的值等于  **a + (b - a) * t** （也可以写作  **a * (1-t) + b*t** ）。
当 `t` = 0 时，**Vector3.Lerp(a, b, t)** 返回 /a/。
当 `t` = 1 时，**Vector3.Lerp(a, b, t)** 返回 /b/。
当 `t` = 0.5 时，**Vector3.Lerp(a, b, t)** 返回 `a` 和 `b` 中间的点。

```
// A short example of Vector3.Lerp usage.
// Add it to an object in your scene, and at Play time it will draw in the Scene View a small yellow line between the scene origin, and a position interpolated between two other positions (one on the up axis, one on the forward axis).

using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    public int interpolationFramesCount = 45; // Number of frames to completely interpolate between the 2 positions
    int elapsedFrames = 0;

void Update()
    {
        float interpolationRatio = (float)elapsedFrames / interpolationFramesCount;

Vector3 interpolatedPosition = Vector3.Lerp(Vector3.up, Vector3.forward, interpolationRatio);

elapsedFrames = (elapsedFrames + 1) % (interpolationFramesCount + 1);  // reset elapsedFrames to zero after it reached (interpolationFramesCount + 1)

Debug.DrawLine(Vector3.zero, Vector3.up, Color.green);
        Debug.DrawLine(Vector3.zero, Vector3.forward, Color.blue);
        Debug.DrawLine(Vector3.zero, interpolatedPosition, Color.yellow);
    }
}
```

```
// A longer example of Vector3.Lerp usage.
// Drop this script under an object in your scene, and specify 2 other objects in the "startMarker"/"endMarker" variables in the script inspector window.
// At play time, the script will move the object along a path between the position of those two markers.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    // Transforms to act as start and end markers for the journey.
    public Transform startMarker;
    public Transform endMarker;

// Movement speed in units per second.
    public float speed = 1.0F;

// Time when the movement started.
    private float startTime;

// Total distance between the markers.
    private float journeyLength;

void Start()
    {
        // Keep a note of the time the movement started.
        startTime = Time.time;

// Calculate the journey length.
        journeyLength = Vector3.Distance(startMarker.position, endMarker.position);
    }

// Move to the target end position.
    void Update()
    {
        // Distance moved equals elapsed time times speed..
        float distCovered = (Time.time - startTime) * speed;

// Fraction of journey completed equals current distance divided by total distance.
        float fractionOfJourney = distCovered / journeyLength;

// Set our position as a fraction of the distance between the markers.
        transform.position = Vector3.Lerp(startMarker.position, endMarker.position, fractionOfJourney);
    }
}
```

另请参阅：[Slerp](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.Slerp.html)、[LerpUnclamped](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.LerpUnclamped.html)。