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VRTK插件详解二：交互之事件与委托分析

2017-03-24 16:33 423 查看
1、我们先来将SteamVR_Unity_Toolkit.unitypackage这个包导入，Asset Store里免费下载

2、当Unity熟练到一定程度，事件与委托是必备的基础！所以本文默认我们已经走过基础阶段。交互设计的精华也在于事件与委托的巧妙设计与实现。VR里的交互更不例外

这篇博客，从SteamVR_Unity_Toolkit的代码里剖析下，它是怎么封装SteamVR的事件的。

3、看类VRTK_ControllerEvents.cs

namespace VRTK{    using UnityEngine;    using System.Collections;
public struct ControllerInteractionEventArgs    {        public uint controllerIndex;        public float buttonPressure;        public Vector2 touchpadAxis;        public float touchpadAngle;    }
public delegate void ControllerInteractionEventHandler(object sender, ControllerInteractionEventArgs e);
public class VRTK_ControllerEvents : MonoBehaviour    {        public enum ButtonAlias        {            Trigger,            Grip,            Touchpad_Touch,            Touchpad_Press,            Application_Menu        }
public ButtonAlias pointerToggleButton = ButtonAlias.Grip;        public ButtonAlias grabToggleButton = ButtonAlias.Trigger;        public ButtonAlias useToggleButton = ButtonAlias.Trigger;        public ButtonAlias menuToggleButton = ButtonAlias.Application_Menu;
public int axisFidelity = 1;
public bool triggerPressed = false;        public bool triggerAxisChanged = false;        public bool applicationMenuPressed = false;        public bool touchpadPressed = false;        public bool touchpadTouched = false;        public bool touchpadAxisChanged = false;        public bool gripPressed = false;
public bool pointerPressed = false;        public bool grabPressed = false;        public bool usePressed = false;        public bool menuPressed = false;
public event ControllerInteractionEventHandler TriggerPressed;        public event ControllerInteractionEventHandler TriggerReleased;
public event ControllerInteractionEventHandler TriggerAxisChanged;
public event ControllerInteractionEventHandler ApplicationMenuPressed;        public event ControllerInteractionEventHandler ApplicationMenuReleased;
public event ControllerInteractionEventHandler GripPressed;        public event ControllerInteractionEventHandler GripReleased;
public event ControllerInteractionEventHandler TouchpadPressed;        public event ControllerInteractionEventHandler TouchpadReleased;
public event ControllerInteractionEventHandler TouchpadTouchStart;        public event ControllerInteractionEventHandler TouchpadTouchEnd;
public event ControllerInteractionEventHandler TouchpadAxisChanged;
public event ControllerInteractionEventHandler AliasPointerOn;        public event ControllerInteractionEventHandler AliasPointerOff;
public event ControllerInteractionEventHandler AliasGrabOn;        public event ControllerInteractionEventHandler AliasGrabOff;
public event ControllerInteractionEventHandler AliasUseOn;        public event ControllerInteractionEventHandler AliasUseOff;
public event ControllerInteractionEventHandler AliasMenuOn;        public event ControllerInteractionEventHandler AliasMenuOff;
private uint controllerIndex;        private SteamVR_TrackedObject trackedController;        private SteamVR_Controller.Device device;
private Vector2 touchpadAxis = Vector2.zero;        private Vector2 triggerAxis = Vector2.zero;
public virtual void OnTriggerPressed(ControllerInteractionEventArgs e)        {            if (TriggerPressed != null)                TriggerPressed(this, e);        }
public virtual void OnTriggerReleased(ControllerInteractionEventArgs e)        {            if (TriggerReleased != null)                TriggerReleased(this, e);        }
public virtual void OnTriggerAxisChanged(ControllerInteractionEventArgs e)        {            if (TriggerAxisChanged != null)                TriggerAxisChanged(this, e);        }
public virtual void OnApplicationMenuPressed(ControllerInteractionEventArgs e)        {            if (ApplicationMenuPressed != null)                ApplicationMenuPressed(this, e);        }
public virtual void OnApplicationMenuReleased(ControllerInteractionEventArgs e)        {            if (ApplicationMenuReleased != null)                ApplicationMenuReleased(this, e);        }
public virtual void OnGripPressed(ControllerInteractionEventArgs e)        {            if (GripPressed != null)                GripPressed(this, e);        }
public virtual void OnGripReleased(ControllerInteractionEventArgs e)        {            if (GripReleased != null)                GripReleased(this, e);        }
public virtual void OnTouchpadPressed(ControllerInteractionEventArgs e)        {            if (TouchpadPressed != null)                TouchpadPressed(this, e);        }
public virtual void OnTouchpadReleased(ControllerInteractionEventArgs e)        {            if (TouchpadReleased != null)                TouchpadReleased(this, e);        }
public virtual void OnTouchpadTouchStart(ControllerInteractionEventArgs e)        {            if (TouchpadTouchStart != null)                TouchpadTouchStart(this, e);        }
public virtual void OnTouchpadTouchEnd(ControllerInteractionEventArgs e)        {            if (TouchpadTouchEnd != null)                TouchpadTouchEnd(this, e);        }
public virtual void OnTouchpadAxisChanged(ControllerInteractionEventArgs e)        {            if (TouchpadAxisChanged != null)                TouchpadAxisChanged(this, e);        }
public virtual void OnAliasPointerOn(ControllerInteractionEventArgs e)        {            if (AliasPointerOn != null)                AliasPointerOn(this, e);        }
public virtual void OnAliasPointerOff(ControllerInteractionEventArgs e)        {            if (AliasPointerOff != null)                AliasPointerOff(this, e);        }
public virtual void OnAliasGrabOn(ControllerInteractionEventArgs e)        {            if (AliasGrabOn != null)                AliasGrabOn(this, e);        }
public virtual void OnAliasGrabOff(ControllerInteractionEventArgs e)        {            if (AliasGrabOff != null)                AliasGrabOff(this, e);        }
public virtual void OnAliasUseOn(ControllerInteractionEventArgs e)        {            if (AliasUseOn != null)                AliasUseOn(this, e);        }
public virtual void OnAliasUseOff(ControllerInteractionEventArgs e)        {            if (AliasUseOff != null)                AliasUseOff(this, e);        }
public virtual void OnAliasMenuOn(ControllerInteractionEventArgs e)        {            if (AliasMenuOn != null)                AliasMenuOn(this, e);        }
public virtual void OnAliasMenuOff(ControllerInteractionEventArgs e)        {            if (AliasMenuOff != null)                AliasMenuOff(this, e);        }
ControllerInteractionEventArgs SetButtonEvent(ref bool buttonBool, bool value, float buttonPressure)        {            buttonBool = value;            ControllerInteractionEventArgs e;            e.controllerIndex = controllerIndex;            e.buttonPressure = buttonPressure;            e.touchpadAxis = device.GetAxis();
float angle = Mathf.Atan2(e.touchpadAxis.y, e.touchpadAxis.x) * Mathf.Rad2Deg;            angle = 90.0f - angle;            if (angle < 0)                angle += 360.0f;
e.touchpadAngle = angle;
return e;        }
void Awake()        {            trackedController = GetComponent<SteamVR_TrackedObject>();        }
void Start()        {            controllerIndex = (uint)trackedController.index;            device = SteamVR_Controller.Input((int)controllerIndex);        }
void EmitAlias(ButtonAlias type, bool touchDown, float buttonPressure, ref bool buttonBool)        {            if (pointerToggleButton == type)            {                if (touchDown)                {                    pointerPressed = true;                    OnAliasPointerOn(SetButtonEvent(ref buttonBool, true, buttonPressure));                }                else                {                    pointerPressed = false;                    OnAliasPointerOff(SetButtonEvent(ref buttonBool, false, buttonPressure));                }            }
if (grabToggleButton == type)            {                if (touchDown)                {                    grabPressed = true;                    OnAliasGrabOn(SetButtonEvent(ref buttonBool, true, buttonPressure));                }                else                {                    grabPressed = false;                    OnAliasGrabOff(SetButtonEvent(ref buttonBool, false, buttonPressure));                }            }
if (useToggleButton == type)            {                if (touchDown)                {                    usePressed = true;                    OnAliasUseOn(SetButtonEvent(ref buttonBool, true, buttonPressure));                }                else                {                    usePressed = false;                    OnAliasUseOff(SetButtonEvent(ref buttonBool, false, buttonPressure));                }            }
if (menuToggleButton == type)            {                if (touchDown)                {                    menuPressed = true;                    OnAliasMenuOn(SetButtonEvent(ref buttonBool, true, buttonPressure));                }                else                {                    menuPressed = false;                    OnAliasMenuOff(SetButtonEvent(ref buttonBool, false, buttonPressure));                }            }        }
bool Vector2ShallowEquals(Vector2 vectorA, Vector2 vectorB)        {            return (vectorA.x.ToString("F" + axisFidelity) == vectorB.x.ToString("F" + axisFidelity) &&                    vectorA.y.ToString("F" + axisFidelity) == vectorB.y.ToString("F" + axisFidelity));        }
void Update()        {            controllerIndex = (uint)trackedController.index;            device = SteamVR_Controller.Input((int)controllerIndex);
Vector2 currentTriggerAxis = device.GetAxis(Valve.VR.EVRButtonId.k_EButton_SteamVR_Trigger);            Vector2 currentTouchpadAxis = device.GetAxis();
if (Vector2ShallowEquals(triggerAxis, currentTriggerAxis))            {                triggerAxisChanged = false;            }            else            {                OnTriggerAxisChanged(SetButtonEvent(ref triggerAxisChanged, true, currentTriggerAxis.x));            }
if (Vector2ShallowEquals(touchpadAxis, currentTouchpadAxis))            {                touchpadAxisChanged = false;            }            else            {                OnTouchpadAxisChanged(SetButtonEvent(ref touchpadTouched, true, 1f));                touchpadAxisChanged = true;            }
touchpadAxis = new Vector2(currentTouchpadAxis.x, currentTouchpadAxis.y);            triggerAxis = new Vector2(currentTriggerAxis.x, currentTriggerAxis.y);
//Trigger            if (device.GetTouchDown(SteamVR_Controller.ButtonMask.Trigger))            {                OnTriggerPressed(SetButtonEvent(ref triggerPressed, true, currentTriggerAxis.x));                EmitAlias(ButtonAlias.Trigger, true, currentTriggerAxis.x, ref triggerPressed);            }            else if (device.GetTouchUp(SteamVR_Controller.ButtonMask.Trigger))            {                OnTriggerReleased(SetButtonEvent(ref triggerPressed, false, 0f));                EmitAlias(ButtonAlias.Trigger, false, 0f, ref triggerPressed);            }
//ApplicationMenu            if (device.GetTouchDown(SteamVR_Controller.ButtonMask.ApplicationMenu))            {                OnApplicationMenuPressed(SetButtonEvent(ref applicationMenuPressed, true, 1f));                EmitAlias(ButtonAlias.Application_Menu, true, 1f, ref applicationMenuPressed);            }            else if (device.GetTouchUp(SteamVR_Controller.ButtonMask.ApplicationMenu))            {
OnApplicationMenuReleased(SetButtonEvent(ref applicationMenuPressed, false, 0f));                EmitAlias(ButtonAlias.Application_Menu, false, 0f, ref applicationMenuPressed);            }
//Grip            if (device.GetTouchDown(SteamVR_Controller.ButtonMask.Grip))            {                OnGripPressed(SetButtonEvent(ref gripPressed, true, 1f));                EmitAlias(ButtonAlias.Grip, true, 1f, ref gripPressed);            }            else if (device.GetTouchUp(SteamVR_Controller.ButtonMask.Grip))            {                OnGripReleased(SetButtonEvent(ref gripPressed, false, 0f));                EmitAlias(ButtonAlias.Grip, false, 0f, ref gripPressed);            }
//Touchpad Pressed            if (device.GetPressDown(SteamVR_Controller.ButtonMask.Touchpad))            {                OnTouchpadPressed(SetButtonEvent(ref touchpadPressed, true, 1f));                EmitAlias(ButtonAlias.Touchpad_Press, true, 1f, ref touchpadPressed);            }            else if (device.GetPressUp(SteamVR_Controller.ButtonMask.Touchpad))            {                OnTouchpadReleased(SetButtonEvent(ref touchpadPressed, false, 0f));                EmitAlias(ButtonAlias.Touchpad_Press, false, 0f, ref touchpadPressed);            }
//Touchpad Touched            if (device.GetTouchDown(SteamVR_Controller.ButtonMask.Touchpad))            {                OnTouchpadTouchStart(SetButtonEvent(ref touchpadTouched, true, 1f));                EmitAlias(ButtonAlias.Touchpad_Touch, true, 1f, ref touchpadTouched);            }            else if (device.GetTouchUp(SteamVR_Controller.ButtonMask.Touchpad))            {                OnTouchpadTouchEnd(SetButtonEvent(ref touchpadTouched, false, 0f));                EmitAlias(ButtonAlias.Touchpad_Touch, false, 0f, ref touchpadTouched);            }        }    }}

　　在这个类中我们可以看到，枚举类ButtonAlias里的元素，分别对应HTCVive控制柄上的按钮：

Trigger：能扣动的那个按钮；

Grip：控制柄侧面的两个按钮；

Touchpad_Touch：触摸板的触控；

Touchpad_Press：触摸板的按压；

Application_Menu：触摸板上方的小按钮，触摸板下方的按钮是统一的总菜单功能键，不能自定义开发，所以没有与它对应的名称。（这句是我的理解，但没有试验过，如果哪位试过，望告知...）

ControllerInteractionEventHandler类型的委托方法有：

TriggerPressed——扳机按下；

TriggerReleased——扳机放开；

TriggerAxisChanged——扳机轴值的改变；

ApplicationMenuPressed——ApplicationMenu按钮按下；

ApplicationMenuReleased——ApplicationMenu按钮放开；

GripPressed——Grip按钮按下；

GripReleased——Grip按钮放开；

TouchpadPressed——触摸板按钮按下；

TouchpadReleased——触摸板按钮放开；

TouchpadTouchStart——触摸板开始触摸；

TouchpadTouchEnd——触摸板结束触摸；

TouchpadAxisChanged——触摸板触摸时的轴值变化；

AliasPointerOn；

AliasPointerOff；

AliasGrabOn；

AliasGrabOff；

AliasUseOn；

AliasUseOff；

AliasMenuOn；

AliasMenuOff；

接下来，我们来看下，Toolkit具体是怎么自己封装的SteamVR控制柄的事件的。

　　在VRTK_ControllerEvents.cs这个脚本的Update()中，我们先找到这样一段代码：



　　从这段代码中（代码的意思很简单，我就不说了，具体看下它的逻辑处理），我们可以看到，每帧监听一次SteamVR中的控制柄状态，当监听到状态后，执行一次自己的委托事件（ControllerInteractionEventHandler），并且执行一次EmitAlias(ButtonAlias type, bool touchDown, float buttonPressure, ref bool buttonBool)方法。EmitAlias方法是用来判断并分发事件给AliasXX(oN/oFF)的（就是刚才分割线以下的那些委托方法）。

　　至于AliasXX(oN/oFF)这些委托方法怎么用？我们可以先看下这个VRTK_ControllerEvents.cs挂接脚本在Inspector面板中的序列化属性：



　　AliasXX(oN/oFF)委托方法对应：


　　至于Inspector面板中的其它属性，都没有实际用处，不需要我们去自定义，所以如果不想看到的话，可以自己在脚本中的相应变量上加上[HideInInspector]，最后：



　　Tollkit对SteamVR的封装逻辑很简单，用这么长的篇幅来说，主要目的还是想自己再仔细研究下，虽然它的逻辑简单，但是我觉的它的代码结构很漂亮。不感兴趣的，可以忽略。至于怎么用，Toolkit也给出了一个挂接脚本，很简单的用法，我挂一下它的代码就行，看完很容易理解：

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using UnityEngine;using System.Collections;using VRTK;
public class VRTK_ControllerEvents_ListenerExample : MonoBehaviour {
// Use this for initialization	void Start () {        if (GetComponent<VRTK_ControllerEvents>() == null)        {            Debug.LogError("VRTK_ControllerEvents_ListenerExample is required to be attached to a SteamVR Controller that has the VRTK_ControllerEvents script attached to it");            return;        }                //Setup controller event listeners        GetComponent<VRTK_ControllerEvents>().TriggerPressed += new ControllerInteractionEventHandler(DoTriggerPressed);        GetComponent<VRTK_ControllerEvents>().TriggerReleased += new ControllerInteractionEventHandler(DoTriggerReleased);
GetComponent<VRTK_ControllerEvents>().TriggerAxisChanged += new ControllerInteractionEventHandler(DoTriggerAxisChanged);
GetComponent<VRTK_ControllerEvents>().ApplicationMenuPressed += new ControllerInteractionEventHandler(DoApplicationMenuPressed);        GetComponent<VRTK_ControllerEvents>().ApplicationMenuReleased += new ControllerInteractionEventHandler(DoApplicationMenuReleased);
GetComponent<VRTK_ControllerEvents>().GripPressed += new ControllerInteractionEventHandler(DoGripPressed);        GetComponent<VRTK_ControllerEvents>().GripReleased += new ControllerInteractionEventHandler(DoGripReleased);
GetComponent<VRTK_ControllerEvents>().TouchpadPressed += new ControllerInteractionEventHandler(DoTouchpadPressed);        GetComponent<VRTK_ControllerEvents>().TouchpadReleased += new ControllerInteractionEventHandler(DoTouchpadReleased);
GetComponent<VRTK_ControllerEvents>().TouchpadTouchStart += new ControllerInteractionEventHandler(DoTouchpadTouchStart);        GetComponent<VRTK_ControllerEvents>().TouchpadTouchEnd += new ControllerInteractionEventHandler(DoTouchpadTouchEnd);
GetComponent<VRTK_ControllerEvents>().TouchpadAxisChanged += new ControllerInteractionEventHandler(DoTouchpadAxisChanged);    }
void DebugLogger(uint index, string button, string action, ControllerInteractionEventArgs e)    {        Debug.Log("Controller on index '" + index + "' " + button + " has been " + action                 + " with a pressure of " + e.buttonPressure + " / trackpad axis at: " + e.touchpadAxis + " (" + e.touchpadAngle + " degrees)");    }
void DoTriggerPressed(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TRIGGER", "pressed down", e);    }
void DoTriggerReleased(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TRIGGER", "released", e);    }
void DoTriggerAxisChanged(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TRIGGER", "axis changed", e);    }
void DoApplicationMenuPressed(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "APPLICATION MENU", "pressed down", e);    }
void DoApplicationMenuReleased(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "APPLICATION MENU", "released", e);    }
void DoGripPressed(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "GRIP", "pressed down", e);    }
void DoGripReleased(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "GRIP", "released", e);    }
void DoTouchpadPressed(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TOUCHPAD", "pressed down", e);    }
void DoTouchpadReleased(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TOUCHPAD", "released", e);    }
void DoTouchpadTouchStart(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TOUCHPAD", "touched", e);    }
void DoTouchpadTouchEnd(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TOUCHPAD", "untouched", e);    }
void DoTouchpadAxisChanged(object sender, ControllerInteractionEventArgs e)    {        DebugLogger(e.controllerIndex, "TOUCHPAD", "axis changed", e);    }}


                                            

                                        

                        
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