Vuforia - 如何在识别图像时播放一个视频

Question

我有一个AR应用程序，它有4个图像目标，每个图像目标有一个相应的视频，当它被识别时在它上面播放。问题在于，即使在识别图像时显示正确的动画，也会播放所有其他动画，即使它们未被显示。因此，每当我从一个图像目标移动到另一个图像目标时，就会显示视频，但它已经在运行时间的一半。

我希望每个视频在识别其父图像目标时启动，但仅限于该特定视频。我需要控制每个图像目标/视频的可跟踪行为。

我怎样才能做到这一点？我知道我需要在Unity中查看的脚本是DefaultTrackableEventHandler.cs或mediaPlayerCtrl.cs（这是我用于我从Easy Movie Texture资产获得的视频管理器（视频播放器）的脚本。什么是我需要在这些脚本中编写代码来实现它。这是DefaultTrackableEventHandler.cs代码：

using UnityEngine;
using Vuforia;

/// <summary>
///     A custom handler that implements the ITrackableEventHandler 
interface.
/// </summary>
public class DefaultTrackableEventHandler : MonoBehaviour, 
ITrackableEventHandler
{
#region PRIVATE_MEMBER_VARIABLES

protected TrackableBehaviour mTrackableBehaviour;

#endregion // PRIVATE_MEMBER_VARIABLES

#region UNTIY_MONOBEHAVIOUR_METHODS

protected virtual void Start()
{
    mTrackableBehaviour = GetComponent<TrackableBehaviour>();
    if (mTrackableBehaviour)
        mTrackableBehaviour.RegisterTrackableEventHandler(this);
}

#endregion // UNTIY_MONOBEHAVIOUR_METHODS

#region PUBLIC_METHODS

/// <summary>
///     Implementation of the ITrackableEventHandler function called when the
///     tracking state changes.
/// </summary>
public void OnTrackableStateChanged(
    TrackableBehaviour.Status previousStatus,
    TrackableBehaviour.Status newStatus)
{
    if (newStatus == TrackableBehaviour.Status.DETECTED ||
        newStatus == TrackableBehaviour.Status.TRACKED ||
        newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
    {
        Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " found");
        OnTrackingFound();
    }
    else if (previousStatus == TrackableBehaviour.Status.TRACKED &&
             newStatus == TrackableBehaviour.Status.NOT_FOUND)
    {
        Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " lost");
        OnTrackingLost();
    }
    else
    {
        // For combo of previousStatus=UNKNOWN + newStatus=UNKNOWN|NOT_FOUND
        // Vuforia is starting, but tracking has not been lost or found yet
        // Call OnTrackingLost() to hide the augmentations
        OnTrackingLost();
    }
}

#endregion // PUBLIC_METHODS

#region PRIVATE_METHODS

protected virtual void OnTrackingFound()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);

    // Enable rendering:
    foreach (var component in rendererComponents)
        component.enabled = true;

    // Enable colliders:
    foreach (var component in colliderComponents)
        component.enabled = true;

    // Enable canvas':
    foreach (var component in canvasComponents)
        component.enabled = true;
}


protected virtual void OnTrackingLost()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);

    // Disable rendering:
    foreach (var component in rendererComponents)
        component.enabled = false;

    // Disable colliders:
    foreach (var component in colliderComponents)
        component.enabled = false;

    // Disable canvas':
    foreach (var component in canvasComponents)
        component.enabled = false;
}

#endregion // PRIVATE_METHODS
}

Answer 1

每次跟踪丢失时都必须停止视频，并在找到跟踪时再次启动视频。我不确切知道你的视频资产是如何工作的，但我会使用通用名称/功能让你明白这一点

protected virtual void OnTrackingLost()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);
    var myVideo = GetComponentInChildren<TheVideoClassAttachedToChildOfImageTarget>

    // Disable rendering:
    foreach (var component in rendererComponents)
        component.enabled = false;

    // Disable colliders:
    foreach (var component in colliderComponents)
        component.enabled = false;

    // Disable canvas':
    foreach (var component in canvasComponents)
        component.enabled = false;

    // Stop video
    myVideo.Stop();
}

同样适用于OnTrackingFound

protected virtual void OnTrackingFound()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);
    var myVideo = GetComponentInChildren<TheVideoClassAttachedToChildOfImageTarget>

    // Enable rendering:
    foreach (var component in rendererComponents)
        component.enabled = true;

    // Enable colliders:
    foreach (var component in colliderComponents)
        component.enabled = true;

    // Enable canvas':
    foreach (var component in canvasComponents)
        component.enabled = true;

    // Play the video again from the beggining
    myVideo.Play();
}

Answer 2

protected virtual void OnTrackingFound()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);

    AudioSource[] audios = GetComponentsInChildren<AudioSource>();
    foreach (var audio in audios)
        audio.Play();


    // Enable rendering:
    foreach (var component in rendererComponents)
        component.enabled = true;

    // Enable colliders:
    foreach (var component in colliderComponents)
        component.enabled = true;

    // Enable canvas':
    foreach (var component in canvasComponents)
        component.enabled = true;
    if (_videoHandler != null)
    {
        _videoHandler.Enable(true);
    }
}

OnTrackingLost：

protected virtual void OnTrackingLost()
{
    var rendererComponents = GetComponentsInChildren<Renderer>(true);
    var colliderComponents = GetComponentsInChildren<Collider>(true);
    var canvasComponents = GetComponentsInChildren<Canvas>(true);

    AudioSource[] audios = GetComponentsInChildren<AudioSource>();

    //AudioSource[] allAudioSources = UnityEngine.Object.FindObjectsOfType<AudioSource>();

    foreach (var audio in audios)
        audio.Stop();


    // Disable rendering:
    foreach (var component in rendererComponents)
        component.enabled = false;


    // Disable colliders:
    foreach (var component in colliderComponents)
        component.enabled = false;


    // Disable canvas':
    foreach (var component in canvasComponents)
        component.enabled = false;

    if (_videoHandler != null)
    {
        _videoHandler.Enable(false);
    }
}