本文將以官方案例來說明如何實現(xiàn)移動全息對象操作(211 - chapter4)栖忠。此案例主要涉及到了語音狸相、手勢識別。

實現(xiàn)思路：

• 通過添加的關(guān)鍵字來初始化KeywordRecognizer瘸右；
• 創(chuàng)建一個GestureRecognizer用于實現(xiàn)Manipulation Holographic;
• 通過語音識別調(diào)用對應(yīng)的函數(shù)操作實現(xiàn)選擇不同的GestureRecognizer；
• 通過不同的手勢識別操作來對應(yīng)地向Gaze射線凝視的物體發(fā)送消息實現(xiàn)操作；

以MSDN上官網(wǎng)的demo為例：

Paste_Image.png

首先可以創(chuàng)建一個空物體來管理相關(guān)的Gaze肃晚、Hand惋鸥、Gesture相關(guān)操作。在這里我們將對全息對象的管理腳本(也就是包含語音操作命令)也掛載在此空物體Manager上。

語音輸入 Voice Command

1. 聲明一個KeywordRecognizer ；
2. 聲明一個Dictionary<string, KeywordAction> keywordCollection用于保存關(guān)鍵字和對應(yīng)的關(guān)鍵字函數(shù)；
3. 在Start()函數(shù)中進(jìn)行添加語音關(guān)鍵字暮胧；
4. 在Start()函數(shù)中由添加的關(guān)鍵字字典keywordCollection進(jìn)行對KeywordRecognizer 初始化并開始關(guān)鍵字識別；
5. 對關(guān)鍵字對應(yīng)的操作函數(shù)進(jìn)行編寫。此案例中為MoveAstronautCommand函數(shù)，主要實現(xiàn)將GestureManager.cs腳本中的不同的GestureRecognizer進(jìn)行切換；

**AstronautManager.cs**

using HoloToolkit;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Windows.Speech;

public class AstronautManager : Singleton<AstronautManager>
{
    // KeywordRecognizer object.
    KeywordRecognizer keywordRecognizer;

    // Defines which function to call when a keyword is recognized.
    delegate void KeywordAction(PhraseRecognizedEventArgs args);
    Dictionary<string, KeywordAction> keywordCollection;

    void Start()
    {
        keywordCollection = new Dictionary<string, KeywordAction>();

        // Add keyword to start manipulation.
        keywordCollection.Add("Move Astronaut", MoveAstronautCommand); 

        // Initialize KeywordRecognizer with the previously added keywords.
        keywordRecognizer = new KeywordRecognizer(keywordCollection.Keys.ToArray());
        keywordRecognizer.OnPhraseRecognized += KeywordRecognizer_OnPhraseRecognized;
        keywordRecognizer.Start();
    }

    private void KeywordRecognizer_OnPhraseRecognized(PhraseRecognizedEventArgs args)
    {
        KeywordAction keywordAction;

        if (keywordCollection.TryGetValue(args.text, out keywordAction))
        {
            keywordAction.Invoke(args);
        }
    }

    private void MoveAstronautCommand(PhraseRecognizedEventArgs args)
    {
        GestureManager.Instance.Transition(GestureManager.Instance.ManipulationRecognizer);
    }

    void OnDestroy()
    {
        keywordRecognizer.Dispose();
    }

}

手勢輸入 Gesture Input

手勢識別是HoloLens交互的重要輸入方法之一薯演。HoloLens提供了底層API和高層API，可以滿足不同的手勢定制需求帝嗡。底層API能夠獲取手的位置和速度信息巢寡，高層API則借助手勢識別器來識別預(yù)設(shè)的手勢（包括，單擊舆蝴、雙擊谦絮、長按菱皆、平移等等）。本部分主要是高級API使用挨稿，通過輸入源來識別手勢仇轻。

只需要很少的步驟就能使用GestureRecognizer集成手勢識別：

1. 創(chuàng)建GestureRecognizer實例
2. 注冊指定的手勢類型
3. 訂閱手勢事件
4. 開始手勢識別

**GestureManager.cs**

using HoloToolkit;
using UnityEngine;
using UnityEngine.VR.WSA.Input;

public class GestureManager : Singleton<GestureManager>
{
    // Manipulation gesture recognizer.
    public GestureRecognizer ManipulationRecognizer { get; private set; }

    // Currently active gesture recognizer.
    //此腳本原先有多個GestureManager ，因此由此代表當(dāng)前激活的GestureManager 
    public GestureRecognizer ActiveRecognizer { get; private set; }

    public bool IsManipulating { get; private set; }

    public Vector3 ManipulationPosition { get; private set; }

    void Awake()
    {
       
        // Instantiate the ManipulationRecognizer.
        ManipulationRecognizer = new GestureRecognizer();

        // Add the ManipulationTranslate GestureSetting to the ManipulationRecognizer's RecognizableGestures.
        ManipulationRecognizer.SetRecognizableGestures(
            GestureSettings.ManipulationTranslate);

        // Register for the Manipulation events on the ManipulationRecognizer.
        ManipulationRecognizer.ManipulationStartedEvent += ManipulationRecognizer_ManipulationStartedEvent;
        ManipulationRecognizer.ManipulationUpdatedEvent += ManipulationRecognizer_ManipulationUpdatedEvent;
        ManipulationRecognizer.ManipulationCompletedEvent += ManipulationRecognizer_ManipulationCompletedEvent;
        ManipulationRecognizer.ManipulationCanceledEvent += ManipulationRecognizer_ManipulationCanceledEvent;

    }

    void OnDestroy()
    {
        // Unregister the Manipulation events on the ManipulationRecognizer.
        ManipulationRecognizer.ManipulationStartedEvent -= ManipulationRecognizer_ManipulationStartedEvent;
        ManipulationRecognizer.ManipulationUpdatedEvent -= ManipulationRecognizer_ManipulationUpdatedEvent;
        ManipulationRecognizer.ManipulationCompletedEvent -= ManipulationRecognizer_ManipulationCompletedEvent;
        ManipulationRecognizer.ManipulationCanceledEvent -= ManipulationRecognizer_ManipulationCanceledEvent;
    }

    /// <summary>
    /// Transition to a new GestureRecognizer.
    /// </summary>
    /// <param name="newRecognizer">The GestureRecognizer to transition to.</param>
    public void Transition(GestureRecognizer newRecognizer)     //切換此腳本中的兩個不同功能的手勢識別
    {
        if (newRecognizer == null)      //切換手勢識別必須指定一個Recognizer
        {
            return;
        }

        if (ActiveRecognizer != null)
        {
            if (ActiveRecognizer == newRecognizer)      //如果切換的新的手勢識別是現(xiàn)在正激活的手勢識別奶甘，就說明沒必要切換篷店，直接return
            {
                return;
            }

            ActiveRecognizer.CancelGestures();
            ActiveRecognizer.StopCapturingGestures();
        }

        newRecognizer.StartCapturingGestures();          //此腳本中的兩個手勢識別都是由此語句激活開始的
        ActiveRecognizer = newRecognizer;
    }

    private void ManipulationRecognizer_ManipulationStartedEvent(InteractionSourceKind source, Vector3 position, Ray ray)
    {
        if (HandsManager.Instance.FocusedGameObject != null)
        {
            IsManipulating = true;

            ManipulationPosition = position;

            //HandsManager.Instance.FocusedGameObject追究到下面就是Gaze射線凝視的對象
            HandsManager.Instance.FocusedGameObject.SendMessageUpwards("PerformManipulationStart", position);
        }
    }

    private void ManipulationRecognizer_ManipulationUpdatedEvent(InteractionSourceKind source, Vector3 position, Ray ray)
    {
        if (HandsManager.Instance.FocusedGameObject != null)
        {
            IsManipulating = true;

            ManipulationPosition = position;

            HandsManager.Instance.FocusedGameObject.SendMessageUpwards("PerformManipulationUpdate", position);
        }
    }

    private void ManipulationRecognizer_ManipulationCompletedEvent(InteractionSourceKind source, Vector3 position, Ray ray)
    {
        IsManipulating = false;
    }

    private void ManipulationRecognizer_ManipulationCanceledEvent(InteractionSourceKind source, Vector3 position, Ray ray)
    {
        IsManipulating = false;
    }

}

此腳本中在訂閱的手勢事件中對Gaze凝視的對象進(jìn)行SendMessageUpwards發(fā)送消息：

• 在ManipulationRecognizer_ManipulationStartedEvent中對Gaze凝視的對象發(fā)送的是PerformManipulationStart函數(shù)；
• 在ManipulationRecognizer_ManipulationUpdatedEvent中對Gaze凝視的對象發(fā)送的是PerformManipulationUpdate函數(shù)臭家；

Holographic Action 對象函數(shù)動作

**GestureAction**

using UnityEngine;

/// <summary>
/// GestureAction performs custom actions based on 
/// which gesture is being performed.
/// </summary>
public class GestureAction : MonoBehaviour
{
    private Vector3 manipulationPreviousPosition;

    void PerformManipulationStart(Vector3 position)
    {
        manipulationPreviousPosition = position;
    }

    void PerformManipulationUpdate(Vector3 position)
    {
        if (GestureManager.Instance.IsManipulating)
        {
            Vector3 moveVector = Vector3.zero;
            //Calculate the moveVector as position - manipulationPreviousPosition.
            moveVector = position - manipulationPreviousPosition;

            //Update the manipulationPreviousPosition with the current position.
            manipulationPreviousPosition = position;

            // Increment this transform's position by the moveVector.
            transform.position += moveVector;
        }
    }
}