Vuforia----自定义目标识别
1、侑喏嵋甲插件导入访问https://developer.vuforia.com/downloads/sdk，进入如下界面，并下载vufor足毂忍珩iaSDK的Unity版本。2、创建工程新建一个Unity工程并将下载好的插件导入到Unity中。3、场景搭建删除场景中原有的MainCamera，接着从Vuforia->Prefabs路径下将AR Camera，ImageTarget以及UserDefinedTargetBuilder拖入场景。接着在AR Camera的Inspector面板下添加AppLicenseKey。随后在ImageTarge的Inspector面版下将ImageTarget类型设置为UserDefined，如下图：
2、接下来我们需要添加模型了，这里就用Cube代钣伊帝藻替了，我们在ImageTarget下添加一个Cube。最后创建Button按钮，也就是我们创建自定义识别图最重要的一步。3、编写脚本在Project下新建一个C#脚本，脚本主框架如下：usingUnityEngine;usingSystem.Collections;usingSystem.Collections.Generic;usingSystem.Linq;usingVuforia;publicclassUDTTest: MonoBehaviour,IUserDefinedTargetEventHandler{voidStart (){}publicvoidOnFrameQualityChanged(ImageTargetBuilder.FrameQualityframeQuality) { }publicvoidOnInitialized() { }publicvoidOnNewTrackableSource(TrackableSourcetrackableSource) { }publicvoidBuildNewTarget(){}}这个类当中比较关键的就是IUserDefinedTargetEventHandler这个接口，这个接口中定义了OnFrameQualityChanged，OnInitialized，OnNewTrackableSource这三个方法，我们实现这个接口中的三个方法，并将脚本附加到UserDefinedTargetBuilder上。首先我们需要声明一个UserDefinedTargetBuildingBehaviour类型的变量，接着在Start函数里将当前类注册为该类型事件。UserDefinedTargetBuildingBehaviourmTargetBuildingBehaviour;voidStart (){mTargetBuildingBehaviour = GetComponent<UserDefinedTargetBuildingBehaviour>();if(mTargetBuildingBehaviour){mTargetBuildingBehaviour.RegisterEventHandler(this);Debug.Log("Registering User Defined Target event handler.");}}接下来要实现接口中的三个函数，先是OnInitialized，用来初始化一些数据，我们在这个函数里写入下面的代码：publicvoidOnInitialized(){mObjectTracker = TrackerManager.Instance.GetTracker<ObjectTracker>();if(mObjectTracker != null){mBuiltDataSet = mObjectTracker.CreateDataSet();mObjectTracker.ActivateDataSet(mBuiltDataSet);}}这里用到两个新的变量需要提前声明，如下：ObjectTrackermObjectTracker;// 新定义的数据集添加到DataSet里DataSetmBuiltDataSet;接着是OnFrameQualityChanged这个函数，用来更新当前帧质量。我们在里面写入下面的代码：publicvoidOnFrameQualityChanged(ImageTargetBuilder.FrameQualityframeQuality){mFrameQuality = frameQuality;if(mFrameQuality == ImageTargetBuilder.FrameQuality.FRAME_QUALITY_LOW){Debug.Log("Low camera image quality");}}这里的mFrameQuality 是一个用来记录当前帧图像质量的枚举类型，声明如下：ImageTargetBuilder.FrameQualitymFrameQuality = ImageTargetBuilder.FrameQuality.FRAME_QUALITY_NONE;最后也是最重要的一个方法OnNewTrackableSource，代码如下：publicvoidOnNewTrackableSource(TrackableSourcetrackableSource){mTargetCounter++;// Deactivates the dataset firstmObjectTracker.DeactivateDataSet(mBuiltDataSet);// Destroy the oldest target if the dataset is full or the dataset// already contains five user-defined targets.if(mBuiltDataSet.HasReachedTrackableLimit() || mBuiltDataSet.GetTrackables().Count() >= 5){IEnumerable<Trackable> trackables = mBuiltDataSet.GetTrackables();Trackableoldest = null;foreach(Trackabletrackable intrackables){if(oldest == null|| trackable.ID < oldest.ID)oldest = trackable;}if(oldest != null){Debug.Log("Destroying oldest trackable in UDT dataset: "+ oldest.Name);mBuiltDataSet.Destroy(oldest, true);}}// Get predefined trackable and instantiate itImageTargetBehaviourimageTargetCopy = (ImageTargetBehaviour)Instantiate(ImageTargetTemplate);imageTargetCopy.gameObject.name = "UserDefinedTarget-"+ mTargetCounter;// Add the duplicated trackable to the data set and activate itmBuiltDataSet.CreateTrackable(trackableSource, imageTargetCopy.gameObject);// Activate the dataset againmObjectTracker.ActivateDataSet(mBuiltDataSet);}这个函数里需要提前声明的变量有两个，如下：intmTargetCounter;//声明一个公开的ImageTargetBehaviour然后在Unity中赋值publicImageTargetBehaviourImageTargetTemplate;最后一个就是我们自定义的一个函数BuildNewTarget，代码如下：publicvoidBuildNewTarget(){mTargetBuildingBehaviour.BuildNewTarget("test", 50);}然后还需要返回到Unity中进行一些细微的设置调整，将我们的脚本拖到UserDefinedTargetBuilder下，并给ImageTargetTemplate进行赋值，如下图：
3、然后我们在Button上添加点击事件，步骤如下：
4、然后在UserDefinedTargetBuilder上勾选Start scanning automatically，表示开启自动扫描。5、运行工程，首先去拍摄一张图片，界面如下：
5、将我们需要自定义的识别图置于取景框内，点击Button，便可识别出Cube，将识别图移除摄像头取景范围，模型消失，再次扫描刚才的识别图，依然出现模型。如下：
6、至此，Vuforia的自定义目标识别，介绍完毕，大家可以根据自己的需求，发挥想象力，制作出属于自己的炫酷AR产品。