hololens官方教程HoloToolKit中部分代码的理解

1.Gaze Manager

using HoloToolkit;
using UnityEngine;

/// <summary>
/// GazeManager determines the location of the user's gaze, hit position and normals.
/// </summary>
public class GazeManager : Singleton<GazeManager>
{
    [Tooltip("Maximum gaze distance for calculating a hit.")]
    public float MaxGazeDistance = 5.0f;    //The maximum distance within which collides can be detected

    [Tooltip("Select the layers raycast should target.")]
    public LayerMask RaycastLayerMask = Physics.DefaultRaycastLayers;

    /// <summary>
    /// Physics.Raycast result is true if it hits a Hologram.
    /// </summary>
    public bool Hit { get; private set; }

    /// <summary>
    /// HitInfo property gives access
    /// to RaycastHit public members.
    /// </summary>
    public RaycastHit HitInfo { get; private set; }

    /// <summary>
    /// Position of the user's gaze.
    /// </summary>
    public Vector3 Position { get; private set; }

    /// <summary>
    /// RaycastHit Normal direction.
    /// </summary>
    public Vector3 Normal { get; private set; }

    private GazeStabilizer gazeStabilizer;
    private Vector3 gazeOrigin;
    private Vector3 gazeDirection;

    void Awake()
    {
        gazeStabilizer = GetComponent<GazeStabilizer>();
    }

    private void Update()
    {
        gazeOrigin = Camera.main.transform.position;

        gazeDirection = Camera.main.transform.forward;

        gazeStabilizer.UpdateHeadStability(gazeOrigin, Camera.main.transform.rotation);

        gazeOrigin = gazeStabilizer.StableHeadPosition;

        UpdateRaycast();
    }

    /// <summary>
    /// Calculates the Raycast hit position and normal.
    /// </summary>
    private void UpdateRaycast()
    {
        RaycastHit hitInfo;

        Hit = Physics.Raycast(gazeOrigin,
                       gazeDirection,
                       out hitInfo,
                       MaxGazeDistance,
                       RaycastLayerMask);

        HitInfo = hitInfo;

        if (Hit)
        {
            // If raycast hit a hologram...

            Position = hitInfo.point;
            Normal = hitInfo.normal;
        }
        else
        {
            // If raycast did not hit a hologram...
            // Save defaults ...
            Position = gazeOrigin + (gazeDirection * MaxGazeDistance);
            Normal = gazeDirection;
        }
    }
}

bool Hit   光标是否与物体发生了碰撞；
        HitInfo   用来储存碰撞的信息；
        Position   碰撞点，就是gaze的坐标位置（发生了碰撞时，即Hit == true时），

或是gaze的最远的点（由MaxGazeDistance决定，不发生碰撞时，即Hit == false ）
        Normal 碰撞点的法线，就是gaze的点的法向量（Hit == true 时），或是gaze的方向（就是gazeDirection，当Hit == false时）。

2.Gesture Manager

    public GestureRecognizer NavigationRecognizer { get; private set; }

    // Manipulation gesture recognizer.
    public GestureRecognizer ManipulationRecognizer { get; private set; }

    // Currently active gesture recognizer.
    public GestureRecognizer ActiveRecognizer { get; private set; }

    public bool IsNavigating { get; private set; }

    public Vector3 NavigationPosition { get; private set; }

    public bool IsManipulating { get; private set; }

    public Vector3 ManipulationPosition { get; private set; }

两种识别器的声明：Navigation和Manipulation；分别声明两个bool类型，判断当前识别器是否在运行中；声明Vector3坐标；

void Awake()
    {
        /* TODO: DEVELOPER CODING EXERCISE 2.b */

        // 2.b: Instantiate the NavigationRecognizer.
        NavigationRecognizer = new GestureRecognizer();

        // 2.b: Add Tap and NavigationX GestureSettings to the NavigationRecognizer's RecognizableGestures.
        NavigationRecognizer.SetRecognizableGestures(
            GestureSettings.Tap |
            GestureSettings.NavigationX);

        // 2.b: Register for the TappedEvent with the NavigationRecognizer_TappedEvent function.
        NavigationRecognizer.TappedEvent += NavigationRecognizer_TappedEvent;
        // 2.b: Register for the NavigationStartedEvent with the NavigationRecognizer_NavigationStartedEvent function.
        NavigationRecognizer.NavigationStartedEvent += NavigationRecognizer_NavigationStartedEvent;
        // 2.b: Register for the NavigationUpdatedEvent with the NavigationRecognizer_NavigationUpdatedEvent function.
        NavigationRecognizer.NavigationUpdatedEvent += NavigationRecognizer_NavigationUpdatedEvent;
        // 2.b: Register for the NavigationCompletedEvent with the NavigationRecognizer_NavigationCompletedEvent function. 
        NavigationRecognizer.NavigationCompletedEvent += NavigationRecognizer_NavigationCompletedEvent;
        // 2.b: Register for the NavigationCanceledEvent with the NavigationRecognizer_NavigationCanceledEvent function. 
        NavigationRecognizer.NavigationCanceledEvent += NavigationRecognizer_NavigationCanceledEvent;

        // 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;

        ResetGestureRecognizers();
    }

将navigation的可识别操作设置为单击以及横向移动（手指移动的横向分量将被检测），

将manipulation则设定为manipulationTranslate（大概是跟随手平移）

注册两种识别器的开始，更新，完成，撤销事件。

void OnDestroy()
    {
        // 2.b: Unregister the Tapped and Navigation events on the NavigationRecognizer.
        NavigationRecognizer.TappedEvent -= NavigationRecognizer_TappedEvent;

        NavigationRecognizer.NavigationStartedEvent -= NavigationRecognizer_NavigationStartedEvent;
        NavigationRecognizer.NavigationUpdatedEvent -= NavigationRecognizer_NavigationUpdatedEvent;
        NavigationRecognizer.NavigationCompletedEvent -= NavigationRecognizer_NavigationCompletedEvent;
        NavigationRecognizer.NavigationCanceledEvent -= NavigationRecognizer_NavigationCanceledEvent;

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

注销上述事件

public void Transition(GestureRecognizer newRecognizer)
    {
        if (newRecognizer == null)
        {
            return;
        }

        if (ActiveRecognizer != null)
        {
            if (ActiveRecognizer == newRecognizer)
            {
                return;
            }

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

        newRecognizer.StartCapturingGestures();
        ActiveRecognizer = newRecognizer;
    }

两种识别器之间的变换，比如当前为navigation识别模式，调用Transition（ManipulationRecognizer）可以使manipulation识别器开始工作。

 public void ResetGestureRecognizers()
    {
        // Default to the navigation gestures.
        Transition(NavigationRecognizer);
    }

重置识别器（官方Demo中默认操作是旋转，因此默认的识别器是navigation识别器）

private void NavigationRecognizer_NavigationStartedEvent(InteractionSourceKind source, Vector3 relativePosition, Ray ray)
    {
        // 2.b: Set IsNavigating to be true.
        IsNavigating = true;

        // 2.b: Set NavigationPosition to be relativePosition.
        NavigationPosition = relativePosition;
    }

    private void NavigationRecognizer_NavigationUpdatedEvent(InteractionSourceKind source, Vector3 relativePosition, Ray ray)
    {
        // 2.b: Set IsNavigating to be true.
        IsNavigating = true;

        // 2.b: Set NavigationPosition to be relativePosition.
        NavigationPosition = relativePosition;
    }

    private void NavigationRecognizer_NavigationCompletedEvent(InteractionSourceKind source, Vector3 relativePosition, Ray ray)
    {
        // 2.b: Set IsNavigating to be false.
        IsNavigating = false;
    }

    private void NavigationRecognizer_NavigationCanceledEvent(InteractionSourceKind source, Vector3 relativePosition, Ray ray)
    {
        // 2.b: Set IsNavigating to be false.
        IsNavigating = false;
    }

各种navigation识别器发生事件之后执行的操作，此处操作是改变IsNavigating的值，即当前识别器的”工作状态“

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

            ManipulationPosition = position;

            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;
    }

    private void NavigationRecognizer_TappedEvent(InteractionSourceKind source, int tapCount, Ray ray)
    {
        GameObject focusedObject = InteractibleManager.Instance.FocusedGameObject;

        if (focusedObject != null)
        {
            focusedObject.SendMessageUpwards("OnSelect");
        }
    }

manipulation识别事件发生后的操作略有不同，识别开始时让当前焦点物体执行方法PerformManipulationStart（GestureAction中）初始化物体位置信息，

更新事件发生后让当前焦点物体执行方法PerformManipulationUpdate（GestureAction中）进行物体的平移操作。单击事件将执行Interactible脚本中的OnSelect（）方法。