问如何确定ARCore可以同时显示的预制件数量？(使用图像识别)

EN

[Tooltip("Angle in degrees between view direction and positions vector has to be smaller than this to activate the video")]
[SerializeField] private float angleThreshold = 20f;

// if possible already reference this via the Inspector
[SerializeField] private Camera mainCamera;

void Start()
{
    if(!mainCamera) mainCamera = Camera.main;
}

void Update()
{
    // get positions vector
    var direction = (Image.CenterPose.position - mainCamera.transform.position).normalized;
    // get view direction
    var viewDirection = mainCamera.transform.forward;
    // get angle between them
    var angle = Vector3.Angle(viewDirection, direction);

    // optionally you could use only the X axis for the angle check 
    // by eliminating the Y value of both vectors
    // allowing the user to still look up and down 
    //direction = (new Vector3(Image.CenterPose.position.x, 0, Image.CenterPose.position.z) - new Vector3(mainCamera.transform.position.x, 0 , mainCamera.transform.position.z)).normalized;
    //viewDirection = new Vector3(viewDirection.x, 0, viewDirection.z);

    // also check the angle
    if (Image == null || Image.TrackingState != TrackingState.Tracking || angle > angleThreshold)
    {
        // optional: I would also stop the video if no longer in focus
        if (video.isPlaying && video.clip == videoClips[Image.DatabaseIndex]) video.Stop();
        return;
    }

    if (!video.isPlaying)
    {
        video.clip = videoClips[Image.DatabaseIndex];
        video.Play();
    }

    transform.localScale = new Vector3(Image.ExtentX - 1, Image.ExtentZ, 1);
}