@interface ViewController () <ARSCNViewDelegate>
//AR视图：展示3D界面
@property (nonatomic, strong) IBOutlet ARSCNView *sceneView;

@end

    
@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    //场景代理
    self.sceneView.delegate = self;
    
    // 显示帧率
    self.sceneView.showsStatistics = YES;
    
    // 创建一个场景
    SCNScene *scene = [SCNScene sceneNamed:@"art.scnassets/ship.scn"];
    
    // Set the scene to the view
    self.sceneView.scene = scene;
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    // 世界坐标系配置
    ARWorldTrackingSessionConfiguration *configuration = [ARWorldTrackingSessionConfiguration new];
    
    // 运行3D 场景的 会话
    [self.sceneView.session runWithConfiguration:configuration];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    
    // 暂停
    [self.sceneView.session pause];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - ARSCNViewDelegate


//给当前锚点创建一个节点 (node 可以理解成 UIView)
/*
// Override to create and configure nodes for anchors added to the view's session.
- (SCNNode *)renderer:(id<SCNSceneRenderer>)renderer nodeForAnchor:(ARAnchor *)anchor {
    SCNNode *node = [SCNNode new];
 
    // Add geometry to the node...
 
    return node;
}
*/

//会话有错误
- (void)session:(ARSession *)session didFailWithError:(NSError *)error {
    // Present an error message to the user
    
}

//被打断  类似音频播放的时候被打断 eg:前后台切换 来电话  siri
- (void)sessionWasInterrupted:(ARSession *)session {
    // Inform the user that the session has been interrupted, for example, by presenting an overlay
    
}

//会话结束
- (void)sessionInterruptionEnded:(ARSession *)session {
    // Reset tracking and/or remove existing anchors if consistent tracking is required
    
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    //1. 使用场景加载 scn 文件
    
    SCNScene *scene = [SCNScene sceneNamed:@"Models.scnassets/vase/vase.scn"];
    SCNNode *plantNode = scene.rootNode.childNodes[0];
    
    //2. 调整位置 将节点添加到当前屏幕中
    plantNode.position = SCNVector3Make(0, -1, -1);
    
    
    //3. 将飞机节点添加到当前屏幕
    [self.arSceneView.scene.rootNode addChildNode:plantNode];
    
}

[self.view addSubview:xxx];

[scene.rootNode addChildNode:xxxNode];

@interface ARAnchor : NSObject <NSCopying>

//锚点唯一标识
@property (nonatomic, readonly) NSUUID *identifier;

//锚点的旋转变换矩阵，定义了锚点的旋转、位置、缩放。是一个4x4的矩阵
@property (nonatomic, readonly) matrix_float4x4 transform;

//构造方法,一般我们无需构造。因为添加一个3D物体时ARKit会有代理告知我们物体的锚点
- (instancetype)initWithTransform:(matrix_float4x4)transform;

FOUNDATION_EXTERN NSString *const ARErrorDomain;

typedef NS_ERROR_ENUM(ARErrorDomain, ARErrorCode) {
    /** Unsupported session configuration. */
    ARErrorCodeUnsupportedConfiguration   = 100,
    
    /** A sensor required to run the session is not available. */
    ARErrorCodeSensorUnavailable          = 101,
    
    /** A sensor failed to provide the required input. */
    ARErrorCodeSensorFailed               = 102,
    
    /** App does not have permission to use the camera. The user may change this in settings. */
    ARErrorCodeCameraUnauthorized         = 103,
    
    /** World tracking has encountered a fatal error. */
    ARErrorCodeWorldTrackingFailed        = 200,
};

@interface ARFrame : NSObject <NSCopying>

//时间戳
@property (nonatomic, readonly) NSTimeInterval timestamp;

//图片帧
@property (nonatomic, readonly) CVPixelBufferRef capturedImage;

//相机（表示这个ARFrame是哪一个相机的，iPhone7plus有两个摄像机）
@property (nonatomic, copy, readonly) ARCamera *camera;

//返回当前相机捕捉到的锚点数据（当一个3D虚拟模型加入到ARKit中时，锚点值得就是这个模型在AR中的位置）
@property (nonatomic, copy, readonly) NSArray<ARAnchor *> *anchors;

//灯光 指的是灯光强度 一般是0-2000，系统默认1000
@property (nonatomic, strong, nullable, readonly) ARLightEstimate *lightEstimate;

//特征点（应该是捕捉平地或者人脸的，比较苹果有自带的人脸识别功能） 仅限 world 的追踪配置可用
@property (nonatomic, strong, nullable, readonly) ARPointCloud *rawFeaturePoints;

//根据2D坐标点搜索3D模型，这个方法通常用于，当我们在手机屏幕点击某一个点的时候，可以捕捉到这一个点所在的3D模型的位置，至于为什么是一个数组非常好理解。手机屏幕一个是长方形，这是一个二维空间。而相机捕捉到的是一个由这个二维空间射出去的长方体，我们点击屏幕一个点可以理解为在这个长方体的边缘射出一条线，这一条线上可能会有多个3D物体模型
point：2D坐标点（手机屏幕某一点）
ARHitTestResultType：捕捉类型  点还是面
(NSArray<ARHitTestResult *> *)：追踪结果数组

- (NSArray<ARHitTestResult *> *)hitTest:(CGPoint)point types:(ARHitTestResultType)types;

//相机窗口的的坐标变换（可用于相机横竖屏的旋转适配）
-(CGAffineTransform)displayTransformWithViewportSize:(CGSize)viewportSize orientation:(UIInterfaceOrientation)orientation;

@end

@interface ARAnchor (Unavailable)

- (instancetype)init NS_UNAVAILABLE;
+ (instancetype)new NS_UNAVAILABLE;
@end

typedef NS_OPTIONS(NSUInteger, ARHitTestResultType) {
    //点
    ARHitTestResultTypeFeaturePoint              = (1 << 0),
	//水平面 y为0.    
    ARHitTestResultTypeEstimatedHorizontalPlane  = (1 << 1),
    
    //已结存在的平面
    ARHitTestResultTypeExistingPlane             = (1 << 3),
    
    //已结存在的锚点和平面
    ARHitTestResultTypeExistingPlaneUsingExtent  = (1 << 4),
} NS_SWIFT_NAME(ARHitTestResult.ResultType);

@interface ARHitTestResult : NSObject

//捕捉类型
@property (nonatomic, readonly) ARHitTestResultType type;

//3D虚拟物体与相机的距离（单位：米）
@property (nonatomic, readonly) CGFloat distance;

//本地坐标矩阵（世界坐标指的是相机为场景原点的坐标，而每一个3D物体自身有一个场景，本地坐标就是相对于这个场景的坐标）类似于frame和bounds的区别
@property (nonatomic, readonly) matrix_float4x4 localTransform;

//世界坐标矩阵
@property (nonatomic, readonly) matrix_float4x4 worldTransform;

//锚点（3D虚拟物体，在虚拟世界有一个位置，这个位置参数是SceneKit中的SCNVector3：三维矢量），而锚点anchor是这个物体在AR现实场景中的位置，是一个4x4的矩阵
@property (nonatomic, strong, nullable, readonly) ARAnchor *anchor;

@end

@interface ARLightEstimate : NSObject

//环境灯光强度  范围0-2000 默认1000
@property (nonatomic, readonly) CGFloat ambientIntensity;

//环境光温度
@property (nonatomic, readonly) CGFloat ambientColorTemperature;

@end

@interface ARPlaneAnchor : ARAnchor

//平地类型，目前只有一个，就是水平面 
@property (nonatomic, readonly) ARPlaneAnchorAlignment alignment;

//3轴矢量结构体，表示平地的中心点  x/y/z
@property (nonatomic, readonly) vector_float3 center;

//3轴矢量结构体，表示平地的大小（宽度和高度）  x/y/z
@property (nonatomic, readonly) vector_float3 extent;

@end

@interface ARPointCloud : NSObject <NSCopying>

//点数
@property (nonatomic, readonly) NSUInteger count;

//每一个点的位置的集合（结构体带*表示的是结构体数组）
@property (nonatomic, readonly) const vector_float3 *points;

@end

//追踪对其方式
typedef NS_ENUM(NSInteger, ARWorldAlignment) {
    /* 相机位置 vector (0, -1, 0) /
    ARWorldAlignmentGravity,
    /* 相机位置及方向. vector (0, -1, 0)    heading ：(0, 0, -1) */
    ARWorldAlignmentGravityAndHeading,
    /* 相机方向. */
    ARWorldAlignmentCamera
} ;

typedef NS_OPTIONS(NSUInteger, ARPlaneDetection) {
    ARPlaneDetectionNone        = 0,
    ARPlaneDetectionHorizontal  = (1 << 0), //探测平面是水平横向
} ;


@interface ARConfiguration : NSObject <NSCopying>

//当前设备是否支持，一般A9芯片以下设备不支持
@property(class, nonatomic, readonly) BOOL isSupported;

//世界坐标的对齐方式 
@property (nonatomic, readwrite) ARWorldAlignment worldAlignment;

//是否需要自适应灯光效果，默认是YES
@property (nonatomic, readwrite, getter=isLightEstimationEnabled) BOOL lightEstimationEnabled;

@end

//世界会话追踪配置，苹果建议我们使用这个类，这个子类只有一个属性，也就是可以帮助我们追踪相机捕捉到的平地
@interface ARWorldTrackingSessionConfiguration : ARConfiguration

//探测的类型
@property (nonatomic, readwrite) ARPlaneDetection planeDetection;

@end

@interface ARSCNView : SCNView

//代理
@property (nonatomic, weak, nullable) id<ARSCNViewDelegate> delegate;

//AR 会话
@property (nonatomic, strong) ARSession *session;

//场景
@property(nonatomic, strong) SCNScene *scene;

//是否自动适应灯光
@property(nonatomic) BOOL automaticallyUpdatesLighting;

//返回对应节点的锚点，节点是一个3D虚拟物体，它的坐标是虚拟场景中的坐标，而锚点ARAnchor是ARKit中现实世界的坐标
- (nullable ARAnchor *)anchorForNode:(SCNNode *)node;

//返回对应锚点的物体
- (nullable SCNNode *)nodeForAnchor:(ARAnchor *)anchor;

/**


 */
- (NSArray<ARHitTestResult *> *)hitTest:(CGPoint)point types:(ARHitTestResultType)types;

@end

//代理的内部实现了SCNSceneRendererDelegate：scenekit代理 和ARSessionObserver：ARSession监听（KVO机制）
#pragma mark - ARSCNViewDelegate
@protocol ARSCNViewDelegate <SCNSceneRendererDelegate, ARSessionObserver>
@optional

//自定义节点的锚点
- (nullable SCNNode *)renderer:(id <SCNSceneRenderer>)renderer nodeForAnchor:(ARAnchor *)anchor;

//当添加节点是会调用，我们可以通过这个代理方法得知我们添加一个虚拟物体到AR场景下的锚点（AR现实世界中的坐标）
- (void)renderer:(id <SCNSceneRenderer>)renderer didAddNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor;

//将要刷新节点
- (void)renderer:(id <SCNSceneRenderer>)renderer willUpdateNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor;

//已经刷新节点
- (void)renderer:(id <SCNSceneRenderer>)renderer didUpdateNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor;

//移除节点
- (void)renderer:(id <SCNSceneRenderer>)renderer didRemoveNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor;

@end

@interface ARSession : NSObject

//代理
@property (nonatomic, weak) id <ARSessionDelegate> delegate;

//指定代理执行的线程（主线程不会有延迟，子线程会有延迟），不指定的话默认主线程
@property (nonatomic, strong, nullable) dispatch_queue_t delegateQueue;

//相机当前的位置（是由会话追踪配置计算出来的）
@property (nonatomic, copy, nullable, readonly) ARFrame *currentFrame;

//会话配置
@property (nonatomic, copy, nullable, readonly) ARConfiguration *configuration;

//运行会话（这行代码就是开启AR的关键所在）
- (void)runWithConfiguration:(ARConfiguration *)configuration NS_SWIFT_UNAVAILABLE("Use run(_:options:) instead");

//运行会话，只是多了一个参数ARSessionRunOptions：作用就是会话断开重连时的行为。
- (void)runWithConfiguration:(ARConfiguration *)configuration options:(ARSessionRunOptions)options NS_SWIFT_NAME(run(_:options:));

//暂停会话
- (void)pause;

//添加锚点
- (void)addAnchor:(ARAnchor *)anchor NS_SWIFT_NAME(add(anchor:));

//移除锚点
- (void)removeAnchor:(ARAnchor *)anchor NS_SWIFT_NAME(remove(anchor:));

@end

typedef NS_OPTIONS(NSUInteger, ARSessionRunOptions) {
	 //表示重置追踪
    ARSessionRunOptionResetTracking           = (1 << 0),
    
    //移除现有锚点
    ARSessionRunOptionRemoveExistingAnchors   = (1 << 1)
};

@protocol ARSessionObserver <NSObject>

@optional

//session 失败
- (void)session:(ARSession *)session didFailWithError:(NSError *)error;

//相机追踪状态发生改变
- (void)session:(ARSession *)session cameraDidChangeTrackingState:(ARCamera *)camera;

//session 意外断开（如果开启ARSession之后，APP退到后台就有可能导致会话断开）
- (void)sessionWasInterrupted:(ARSession *)session;

//session 会话断开后 恢复(短时间退到后台再进入APP会自动恢复）
- (void)sessionInterruptionEnded:(ARSession *)session;

//session 已经输出了一个 音频数据 `CMSampleBufferRef` 
- (void)session:(ARSession *)session didOutputAudioSampleBuffer:(CMSampleBufferRef)audioSampleBuffer;

@end

相机位置发生改变 就是相机的位置有变动
- (void)session:(ARSession *)session didUpdateFrame:(ARFrame *)frame;

// 已添加锚点
- (void)session:(ARSession *)session didAddAnchors:(NSArray<ARAnchor*>*)anchors;

//刷新锚点
- (void)session:(ARSession *)session didUpdateAnchors:(NSArray<ARAnchor*>*)anchors;

//移除锚点
- (void)session:(ARSession *)session didRemoveAnchors:(NSArray<ARAnchor*>*)anchors;

@end

@interface ARCamera : NSObject <NSCopying>

//4x4矩阵表示相机位置 跟锚点类似
@property (nonatomic, readonly) matrix_float4x4 transform;

//相机方向（旋转）的矢量欧拉角 分别是x/y/z
@property (nonatomic, readonly) vector_float3 eulerAngles;

//相机追踪状态（在下方会有枚举值介绍）
@property (nonatomic, readonly) ARTrackingState trackingState NS_REFINED_FOR_SWIFT;

//追踪运动类型
@property (nonatomic, readonly) ARTrackingStateReason trackingStateReason NS_REFINED_FOR_SWIFT;

//相机曲率 3x3矩阵  
@property (nonatomic, readonly) matrix_float3x3 intrinsics;

//摄像头分辨率
@property (nonatomic, readonly) CGSize imageResolution;

//投影矩阵
@property (nonatomic, readonly) matrix_float4x4 projectionMatrix;


//创建相机 使用x,y,z 位置 
- (CGPoint)projectPoint:(vector_float3)point orientation:(UIInterfaceOrientation)orientation viewportSize:(CGSize)viewportSize;
 
//创建相机投影矩阵 近面距离  远面距离
- (matrix_float4x4)projectionMatrixForOrientation:(UIInterfaceOrientation)orientation viewportSize:(CGSize)viewportSize zNear:(CGFloat)zNear zFar:(CGFloat)zFar;

//创建相机投影矩阵
- (matrix_float4x4)viewMatrixForOrientation:(UIInterfaceOrientation)orientation;

@end

//相机追踪状态枚举
typedef NS_ENUM(NSInteger, ARTrackingState) {
	 /* 不被允许 */
    ARTrackingStateNotAvailable,
    
    /* 最小 */
    ARTrackingStateLimited,
    
    /* 正常. */
    ARTrackingStateNormal,
};

//追踪运动类型
typedef NS_ENUM(NSInteger, ARTrackingStateReason) {
    /* 无. */
    ARTrackingStateReasonNone,
    
    //初始化
    ARTrackingStateReasonInitializing,
    
    /* 运动. */
    ARTrackingStateReasonExcessiveMotion,
    
    /** 脸部捕捉. */
    ARTrackingStateReasonInsufficientFeatures,
}

#pragma mark -
#pragma mark - ARSCNViewDelegate 代理

- (void)renderer:(id <SCNSceneRenderer>)renderer didAddNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor{
    if ([anchor isMemberOfClass:[ARPlaneAnchor class]]) {
        NSLog(@"捕捉到平地");
        //添加一个3D 平面模型,ARKit 只有捕捉能力,锚点是一个空间位置,要想更加清楚的看到这个空间,我们需要给空间添加一个平地的3D模型来渲染他
        //1. 获取扑捉到的平地锚点
        ARPlaneAnchor *planeAnchor = (ARPlaneAnchor *)anchor;
        //2. 创建一个3D物体模型 (系统捕捉到的平地是一个不规则大小的长方形，这里我们将其变成一个长方形，并且对平地做一次缩放）
        //创建长方形  参数:长,宽,高,圆角
        SCNBox *plane = [SCNBox boxWithWidth:planeAnchor.extent.x * 0.3 height:0 length:planeAnchor.extent.x * 0.3 chamferRadius:0];
        //3. 使用Material渲染3D模型 默认模型是白色的
        plane.firstMaterial.diffuse.contents = [UIColor cyanColor];
        
        //4. 创建一个基于3D 物体模型的节点
        SCNNode *planeNode = [SCNNode nodeWithGeometry:plane];
        //5. 设置节点的位置为捕捉到的平地的锚点和中心位置 SceneKit框架中节点的位置position是一个基于3D坐标系的矢量坐标SCNVector3Make
        planeNode.position = SCNVector3Make(planeAnchor.center.x, 0, planeAnchor.center.z);
        
        [node addChildNode:planeNode];
        
        //6. 当捕捉到平地时，2s之后开始在平地上添加一个3D模型
        
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            //1.创建一个花瓶场景
            SCNScene *scene = [SCNScene sceneNamed:@"Models.scnassets/vase/vase.scn"];
            //2.获取花瓶节点（一个场景会有多个节点，此处我们只写，花瓶节点则默认是场景子节点的第一个）
            //所有的场景有且只有一个根节点，其他所有节点都是根节点的子节点
            SCNNode *vaseNode = scene.rootNode.childNodes[0];
            
            //4.设置花瓶节点的位置为捕捉到的平地的位置，如果不设置，则默认为原点位置，也就是相机位置
            vaseNode.position = SCNVector3Make(planeAnchor.center.x, 0, planeAnchor.center.z);
            
            //5.将花瓶节点添加到当前屏幕中
            //!!!此处一定要注意：花瓶节点是添加到代理捕捉到的节点中，而不是AR试图的根节点。因为捕捉到的平地锚点是一个本地坐标系，而不是世界坐标系
            [node addChildNode:vaseNode];
        });
    }
}