如何在统一网络摄像头中修改焦距？

Question

我正在设置统一的webcamtexture的焦距，但是我无法修改相机的焦距...

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class MobileCam : MonoBehaviour {

    private bool camAvailable;
    private WebCamTexture cameraTexture;
    //private Texture defaultBackground;

    public RawImage background;
    public AspectRatioFitter fit;
    public bool frontFacing;

    // Use this for initialization
    void Start () {
        //defaultBackground = background.texture;
        WebCamDevice[] devices = WebCamTexture.devices;

        if (devices.Length == 0)
            return;

        for (int i = 0; i < devices.Length; i++)
        {
            var curr = devices[i];

            if (curr.isFrontFacing == frontFacing)
            {
                //1280*720
                cameraTexture = new WebCamTexture(curr.name, Screen.currentResolution.width, Screen.currentResolution.height);
                break;
            }
        }

        if (cameraTexture == null)
            return;

        cameraTexture.Play (); // Start the camera
        background.texture = cameraTexture; // Set the texture

        camAvailable = true; // Set the camAvailable for future purposes.
    }

    // Update is called once per frame
    void Update () {
        if (!camAvailable)
            return;

        //float ratio = (float)cameraTexture.width / (float)cameraTexture.height;//3/2=1.3333 Vertical=2/3=0.666
        //fit.aspectRatio = ratio; // Set the aspect ratio
        float ratio = (float)cameraTexture.height / (float)cameraTexture.width  ;//3/2=1.3333 Vertical=2/3=0.666
        fit.aspectRatio = ratio; // Set the aspect ratio

        float scaleY = cameraTexture.videoVerticallyMirrored ? -1f : 1f; // Find if the camera is mirrored or not
        background.rectTransform.localScale = new Vector3(1f, scaleY, 1f); // Swap the mirrored camera

        int orient = -cameraTexture.videoRotationAngle;
        background.rectTransform.localEulerAngles = new Vector3(0,0, orient);
    }
}

当我使用此代码时，相机的缩放比例非常不同。

我在下面附上了屏幕截图

1.Vuforia焦距预览：： Vuforia Link

2。第二摄像机预览：:

Second Camera Link