Camera.ScreenPointToRay

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

public [Ray](https://docs.unity3d.com/cn/2019.4/ScriptReference/Ray.html) **ScreenPointToRay** ([Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **pos**);

public [Ray](https://docs.unity3d.com/cn/2019.4/ScriptReference/Ray.html) **ScreenPointToRay** ([Vector3](https://docs.unity3d.com/cn/2019.4/ScriptReference/Vector3.html) **pos**, [Camera.MonoOrStereoscopicEye](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera.MonoOrStereoscopicEye.html) **eye**);

## 参数

| eye | 可选参数，可用于指定要使用的眼睛变换。默认值为 Mono。 |
| ----- | ------------------------------------------------------- |

## 描述

返回从摄像机通过屏幕点的光线。

产生的光线位于世界空间中，从摄像机的近平面开始，并通过屏幕上 位置的 (x,y) 像素坐标（忽略 position.z）。

屏幕空间以像素定义。屏幕的左下角为 (0,0)，右上角为 ([pixelWidth](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera-pixelWidth.html) -1,[pixelHeight](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera-pixelHeight.html) -1)。

```
//Attach this script to your Camera
//This draws a line in the Scene view going through a point 200 pixels from the lower-left corner of the screen
//To see this, enter Play Mode and switch to the Scene tab. Zoom into your Camera's position.
using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    Camera cam;
    Vector3 pos = new Vector3(200, 200, 0);

void Start()
    {
        cam = GetComponent<Camera>();
    }

void Update()
    {
        Ray ray = cam.ScreenPointToRay(pos);
        Debug.DrawRay(ray.origin, ray.direction * 10, Color.yellow);
    }
}
```