使用unity + Vuforia实现脱卡识别，多目标情况

本教程基于羽安老师的单目标脱卡识别（http://www.arinchina.com/video/show-1950.html）基础上增加多目标实现脱卡的，在使用本教程之前请先看羽安老师的教程。

Action……………………

当图片识别成功后，将当前组件作为模型的父物体，当图片丢失后，在Camera中新建一个空物体（empty），并将模型作为该空物体的子物体

替换Default Trackable Event Handler脚本：

///NotFound.cs

using UnityEngine;
using System.Collections;
using Vuforia;
using System;
using UnityEngine.SceneManagement;

public class NotFound : MonoBehaviour , ITrackableEventHandler
{

#region PRIVATE_MEMBER_VARIABLES
private TrackableBehaviour mTrackableBehaviour;

//判断是否是第一次识别是否完成，防止开启程序未放入识别图也在屏幕中央出现模型
bool firstfound = false;

public GameObject successImage;

public bool imageIsOut = false;//识别成功的图片是否已经出现过

//模型起始位置，值为起始模型组件中Transform.Position
//Vector3 origposition = new Vector3 (0, 0.25f, 0);
public Vector3 originPosition;

//当前imagetarget对应的模型等target
public Transform[] localTargets;

//其他非当前imagetarget对应的模型等targets
public Transform[] otherTargets;

//Camera Object
GameObject gObject;
//Camera Object的Creat Empty脚本
CreatEmpty cempty;

//表示ImageTarget父物体那个组件
public GameObject[] otherImageTargets;

#region 自定义的协程延时函数
//定义一个延时函数
public static IEnumerator DelayToInvokeDo(Action action, float delaySeconds)

{

yield return new WaitForSeconds(delaySeconds);

action();

}
#endregion //自定义的协程延时函数

void Start()
{
//不显示两张识别成功失败的图片
successImage.SetActive (false);

//相机自动对焦
Vuforia.CameraDevice.Instance.SetFocusMode(Vuforia.CameraDevice.FocusMode.FOCUS_MODE_CONTINUOUSAUTO);

mTrackableBehaviour = GetComponent<TrackableBehaviour>();
if (mTrackableBehaviour)
{
mTrackableBehaviour.RegisterTrackableEventHandler(this);
}

//获取Camera中组件的CreatEmpty脚本
gObject = GameObject.FindWithTag("MainCamera");
cempty = gObject.GetComponent<CreatEmpty> ();
if(cempty != null)
{
//杀死空物体
cempty.destoryempty ();
}
}

void Update()
{
//退出当前程序
if(Input.GetKeyDown(KeyCode.Escape))
{
//Application.Quit();
//Application.LoadLevel("PreschoolEducation-0-MenuScreen");
SceneManager.LoadScene ("PreschoolEducation-0-MenuScreen");
}

}

#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)
{
//Vector3 orirotation = new Vector3 (270, 0, 0);

if (newStatus == TrackableBehaviour.Status.DETECTED ||
newStatus == TrackableBehaviour.Status.TRACKED ||
newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
{

//如果识别成功图片没有出现过，则执行下面的代码，显示并延时0.5秒后消失
if(!imageIsOut)
{
successImage.SetActive (true);

for(int i = 0; i < otherTargets.Length; i++)
{
//但是隐藏其他imagetarget对应的模型，目的是防止在该imagetarget对应的模型出现在屏幕中央的时候不受其他imagetarget对应的模型的影响
//otherTargets[i].gameObject.SetActive (false);
setShow (otherTargets [i], false);
}

for(int i = 0; i < localTargets.Length; i++)
{
//localTargets[i].gameObject.SetActive (false);
setShow (localTargets [i], false);
}

//需要延时0.3s，让图片多显示0.3s后消失(执行outImage函数)
//Invoke ("outImage", 0.5f);//如果这样，并不影响下面代码的执行。

StartCoroutine(DelayToInvokeDo(() =>

{
outImage(newStatus);

//识别成功图片已经显示过了
imageIsOut = true;

}, 0.4f));

}
else
{
OnTrackingFound ();
}

}
else
{

OnTrackingLost ();
}
}

#endregion // PUBLIC_METHODS

//识别成功图片显示并消失之后
private void outImage(TrackableBehaviour.Status newStatus)
{
successImage.SetActive (false);
for(int i = 0; i < otherTargets.Length; i++)
{
//但是隐藏其他imagetarget对应的模型，目的是防止在该imagetarget对应的模型出现在屏幕中央的时候不受其他imagetarget对应的模型的影响
//otherTargets[i].gameObject.SetActive (false);
setShow (otherTargets [i], false);
}

for(int i = 0; i < localTargets.Length; i++)
{
//localTargets[i].gameObject.SetActive (false);
setShow (localTargets [i], false);
}

//显示并消失之后在一次判断图片是否处于追踪状态
if (newStatus == TrackableBehaviour.Status.TRACKED ||
newStatus == TrackableBehaviour.Status.DETECTED ||
newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
{
OnTrackingFound ();
firstfound = true;
}
else
{
//OnTrackingLost ();
for(int i = 0; i < otherTargets.Length; i++)
{
//但是隐藏其他imagetarget对应的模型，目的是防止在该imagetarget对应的模型出现在屏幕中央的时候不受其他imagetarget对应的模型的影响
//otherTargets[i].gameObject.SetActive (false);
setShow (otherTargets [i], false);
}

for(int i = 0; i < localTargets.Length; i++)
{
//localTargets[i].gameObject.SetActive (false);
setShow (localTargets [i], false);
}

}

}

private void OnTrackingFound()
{
Debug.Log ("it is found");
for(int i = 0; i < otherImageTargets.Length; i++)
{
//让其他的识别图在执行一次状态识别成功的代码，使得模型归位到imagetarget子物体
otherImageTargets[i].GetComponent<NotFound> ().homing ();

//当前图片识别成功时，关闭其他图片的识别
//      otherImageTargets[i].SetActive (false);

//将其他识别图中的识别成功图片设置成未显示过
otherImageTargets [i].GetComponent<NotFound> ().imageIsOut = false;

}

for(int i = 0; i < localTargets.Length; i++)
{
//setShow (localTargets [i], true);
//othertargetmodel.gameObject.SetActive (false);

localTargets[i].parent = this.transform;
localTargets[i].localPosition = originPosition;
localTargets[i].rotation = Quaternion.Euler (Vector3.zero);

//开启当前图片对应的模型，因为在识别其他图片的时候有可能关闭了这个图片对应的模型
//localTargets[i].gameObject.SetActive (true);
setShow (localTargets [i], true);
}

//杀死空物体
cempty.destoryempty ();

//因为杀死了空物体，所以一旦丢失跟踪，模型就没地方放了，所以就加一个判断，丢失的话就不显示模型
if(mTrackableBehaviour.CurrentStatus ==TrackableBehaviour.Status.NOT_FOUND)
{
for(int i = 0;i < localTargets.Length; i++)
{
setShow (localTargets [i], false);
}
}

//target.rotation = Quaternion.Euler(orirotation);
//firstfound = true;
}

private void OnTrackingLost()
{
Debug.Log ("it is lost");
for(int i = 0; i < localTargets.Length; i++)
{
//localTargets[i].gameObject.SetActive (false);
setShow (localTargets [i], false);
}

successImage.SetActive (false);
if (firstfound == true)
{
//创建空物体
cempty.creatempty ();

for(int i = 0; i < otherTargets.Length; i++)
{
//但是隐藏其他imagetarget对应的模型，目的是防止在该imagetarget对应的模型出现在屏幕中央的时候不受其他imagetarget对应的模型的影响
//otherTargets[i].gameObject.SetActive (false);
setShow (otherTargets [i], false);
}

GameObject emptyobject = GameObject.Find ("empty");
Transform cameraPos = emptyobject.transform;

for(int i = 0; i < localTargets.Length; i++)
{
//将target作为cameraPos的子物体，cameraPos就是emptyobject(即空物体)的Transform表现形式
localTargets[i].parent = cameraPos;

localTargets[i].localPosition = originPosition;

//target.localRotation = Quaternion.Euler (orirotation);
localTargets[i].localRotation = Quaternion.Euler (Vector3.zero);

//localTargets[i].gameObject.SetActive (true);
setShow (localTargets [i], true);

}

}
else
{

for(int i = 0; i < otherTargets.Length; i++)
{
//但是隐藏其他imagetarget对应的模型，目的是防止在该imagetarget对应的模型出现在屏幕中央的时候不受其他imagetarget对应的模型的影响
//otherTargets[i].gameObject.SetActive (false);
setShow (otherTargets [i], false);
}

for(int i = 0; i < localTargets.Length; i++)
{
print ("local Targets set active false");
//localTargets[i].gameObject.SetActive (false);
setShow (localTargets [i], false);
}

}

}

//方便其他脚本调用的接口函数，使this.中模型归位
public void homing()
{
for(int i = 0; i < localTargets.Length; i++)
{
localTargets[i].parent = this.transform;
localTargets[i].position = originPosition;
localTargets[i].rotation = Quaternion.Euler (Vector3.zero);

}

}

//自己写的隐藏模型代码,仅模型可用
void setShow(Transform target,bool IsShow)
{

Renderer[] targetrendererComponents = target.GetComponentsInChildren<Renderer>(true);
Collider[] targetcolliderComponents = target.GetComponentsInChildren<Collider>(true);

if(IsShow)
{
// enable rendering:
foreach (Renderer component in targetrendererComponents)
{
component.enabled = true;
}

// enable colliders:
foreach (Collider component in targetcolliderComponents)
{
component.enabled = true;
}
}
else
{
// Disable rendering:
foreach (Renderer component in targetrendererComponents)
{
component.enabled = false;
}

// Disable colliders:
foreach (Collider component in targetcolliderComponents)
{
component.enabled = false;
}
}
}

}

在Camera中创建空物体empty：

///CreatEmpty.cs

using UnityEngine;
using System.Collections;
using Vuforia;
public class CreatEmpty : MonoBehaviour {
Vector3 emptyposition = new Vector3 (0, 0, 567);
public void creatempty()
{
//定义一个空物体，并将他作为Camera的子物体，并设置其坐标和旋转角度
GameObject emptyObject = new GameObject ();
emptyObject.transform.parent = GameObject.FindWithTag ("MainCamera").transform;
emptyObject.name = "empty";
emptyObject.transform.localPosition = emptyposition;
emptyObject.transform.localRotation = Quaternion.Euler (Vector3.zero);
}
//杀死camera组件中名字为“empty”的物体
public void destoryempty()
{
if (GameObject.Find ("empty"))
GameObject.Destroy (GameObject.Find ("empty"));
else
print ("没有empty！");
}
}

将NotFound.cs赋到ImageTarget中替换Default Trackable Event Handler脚本，CreatEmpty.cs赋到Camera中。



2016年10月29日更新博客，修复了NotFound脚本中，绑定在模型上的脚本自动隐藏的问题，同时修复了，出现识别成功图片过程中（还未出现模型），迅速让图片目标丢失，模型仍然显示，而且位置乱了的问题。