• 轉(zhuǎn)載請(qǐng)注明出處:ARKit從入門(mén)到精通（9）-ARKit讓飛機(jī)跟著鏡頭飛起來(lái)

• 1.1-ARKit物體跟隨相機(jī)移動(dòng)流程介紹

• 1.2-完整代碼
• 1.3-代碼下載地址

• 廢話不多說(shuō)，先看效果

1001.gif

1.1-ARKit物體跟隨相機(jī)移動(dòng)流程介紹

• 1.點(diǎn)擊屏幕添加物體，已經(jīng)在第三小節(jié)ARKit從入門(mén)到精通（3）-ARKit自定義實(shí)現(xiàn)中介紹

• 2.監(jiān)聽(tīng)ARSession的代理

  • 相機(jī)的移動(dòng)是由AR會(huì)話來(lái)監(jiān)聽(tīng)的

• 3.在ARSession的相機(jī)移動(dòng)代理中獲取相機(jī)的當(dāng)前位置，修改物體的位置與相機(jī)位置一致，即可實(shí)現(xiàn)物體跟隨相機(jī)移動(dòng)而移動(dòng)

• 核心代碼介紹

#pragma mark -ARSessionDelegate//會(huì)話位置更新（監(jiān)聽(tīng)相機(jī)的移動(dòng)），此代理方法會(huì)調(diào)用非常頻繁，只要相機(jī)移動(dòng)就會(huì)調(diào)用，如果相機(jī)移動(dòng)過(guò)快，會(huì)有一定的誤差，具體的需要強(qiáng)大的算法去優(yōu)化，筆者這里就不深入了 - (void)session:(ARSession *)session didUpdateFrame:(ARFrame *)frame {NSLog(@"相機(jī)移動(dòng)");if (self.arType != ARTypeMove) {return;}//移動(dòng)飛機(jī)if (self.planeNode) {//捕捉相機(jī)的位置，讓節(jié)點(diǎn)隨著相機(jī)移動(dòng)而移動(dòng)//根據(jù)官方文檔記錄，相機(jī)的位置參數(shù)在4X4矩陣的第三列self.planeNode.position =SCNVector3Make(frame.camera.transform.columns[3].x,frame.camera.transform.columns[3].y,frame.camera.transform.columns[3].z);}}

1.2-完整代碼

#import "ARSCNViewViewController.h"//3D游戲框架 #import <SceneKit/SceneKit.h> //ARKit框架 #import <ARKit/ARKit.h>@interface ARSCNViewViewController ()<ARSCNViewDelegate,ARSessionDelegate>//AR視圖：展示3D界面 @property(nonatomic,strong)ARSCNView *arSCNView;//AR會(huì)話，負(fù)責(zé)管理相機(jī)追蹤配置及3D相機(jī)坐標(biāo) @property(nonatomic,strong)ARSession *arSession;//會(huì)話追蹤配置：負(fù)責(zé)追蹤相機(jī)的運(yùn)動(dòng) @property(nonatomic,strong)ARSessionConfiguration *arSessionConfiguration;//飛機(jī)3D模型(本小節(jié)加載多個(gè)模型) @property(nonatomic,strong)SCNNode *planeNode;@end@implementation ARSCNViewViewController- (void)viewDidLoad {[super viewDidLoad];// Do any additional setup after loading the view. }- (void)back:(UIButton *)btn {[self dismissViewControllerAnimated:YES completion:nil]; }- (void)viewDidAppear:(BOOL)animated {[super viewDidAppear:animated];//1.將AR視圖添加到當(dāng)前視圖[self.view addSubview:self.arSCNView];//2.開(kāi)啟AR會(huì)話（此時(shí)相機(jī)開(kāi)始工作）[self.arSession runWithConfiguration:self.arSessionConfiguration];//添加返回按鈕UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];[btn setTitle:@"返回" forState:UIControlStateNormal];btn.frame = CGRectMake(self.view.bounds.size.width/2-50, self.view.bounds.size.height-100, 100, 50);btn.backgroundColor = [UIColor greenColor];[btn addTarget:self action:@selector(back:) forControlEvents:UIControlEventTouchUpInside];[self.view addSubview:btn];}#pragma mark- 點(diǎn)擊屏幕添加飛機(jī) - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {if (self.arType == ARTypePlane || self.planeNode != nil) {return;}//1.使用場(chǎng)景加載scn文件（scn格式文件是一個(gè)基于3D建模的文件，使用3DMax軟件可以創(chuàng)建，這里系統(tǒng)有一個(gè)默認(rèn)的3D飛機(jī)）--------在右側(cè)我添加了許多3D模型，只需要替換文件名即可SCNScene *scene = [SCNScene sceneNamed:@"Models.scnassets/ship.scn"];//2.獲取飛機(jī)節(jié)點(diǎn)（一個(gè)場(chǎng)景會(huì)有多個(gè)節(jié)點(diǎn)，此處我們只寫(xiě)，飛機(jī)節(jié)點(diǎn)則默認(rèn)是場(chǎng)景子節(jié)點(diǎn)的第一個(gè)）//所有的場(chǎng)景有且只有一個(gè)根節(jié)點(diǎn)，其他所有節(jié)點(diǎn)都是根節(jié)點(diǎn)的子節(jié)點(diǎn)SCNNode *shipNode = scene.rootNode.childNodes[0];self.planeNode = shipNode;//飛機(jī)比較大，釋放縮放一下并且調(diào)整位置讓其在屏幕中間shipNode.scale = SCNVector3Make(0.5, 0.5, 0.5);shipNode.position = SCNVector3Make(0, -15,-15);;//一個(gè)飛機(jī)的3D建模不是一氣呵成的，可能會(huì)有很多個(gè)子節(jié)點(diǎn)拼接，所以里面的子節(jié)點(diǎn)也要一起改，否則上面的修改會(huì)無(wú)效for (SCNNode *node in shipNode.childNodes) {node.scale = SCNVector3Make(0.5, 0.5, 0.5);node.position = SCNVector3Make(0, -15,-15);}//3.將飛機(jī)節(jié)點(diǎn)添加到當(dāng)前屏幕中[self.arSCNView.scene.rootNode addChildNode:shipNode];}#pragma mark -搭建ARKit環(huán)境//懶加載會(huì)話追蹤配置 - (ARSessionConfiguration *)arSessionConfiguration {if (_arSessionConfiguration != nil) {return _arSessionConfiguration;}//1.創(chuàng)建世界追蹤會(huì)話配置（使用ARWorldTrackingSessionConfiguration效果更加好），需要A9芯片支持ARWorldTrackingSessionConfiguration *configuration = [[ARWorldTrackingSessionConfiguration alloc] init];//2.設(shè)置追蹤方向（追蹤平面，后面會(huì)用到）configuration.planeDetection = ARPlaneDetectionHorizontal;_arSessionConfiguration = configuration;//3.自適應(yīng)燈光（相機(jī)從暗到強(qiáng)光快速過(guò)渡效果會(huì)平緩一些）_arSessionConfiguration.lightEstimationEnabled = YES;return _arSessionConfiguration;}//懶加載拍攝會(huì)話 - (ARSession *)arSession {if(_arSession != nil){return _arSession;}//1.創(chuàng)建會(huì)話_arSession = [[ARSession alloc] init];_arSession.delegate = self;//2返回會(huì)話return _arSession; }//創(chuàng)建AR視圖 - (ARSCNView *)arSCNView {if (_arSCNView != nil) {return _arSCNView;}//1.創(chuàng)建AR視圖_arSCNView = [[ARSCNView alloc] initWithFrame:self.view.bounds];//2.設(shè)置代理 捕捉到平地會(huì)在代理回調(diào)中返回_arSCNView.delegate = self;//2.設(shè)置視圖會(huì)話_arSCNView.session = self.arSession;//3.自動(dòng)刷新燈光（3D游戲用到，此處可忽略）_arSCNView.automaticallyUpdatesLighting = YES;return _arSCNView; }#pragma mark -- ARSCNViewDelegate//添加節(jié)點(diǎn)時(shí)候調(diào)用（當(dāng)開(kāi)啟平地捕捉模式之后，如果捕捉到平地，ARKit會(huì)自動(dòng)添加一個(gè)平地節(jié)點(diǎn)） - (void)renderer:(id <SCNSceneRenderer>)renderer didAddNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor {if(self.arType != ARTypePlane){return;}if ([anchor isMemberOfClass:[ARPlaneAnchor class]]) {NSLog(@"捕捉到平地");//添加一個(gè)3D平面模型，ARKit只有捕捉能力，錨點(diǎn)只是一個(gè)空間位置，要想更加清楚看到這個(gè)空間，我們需要給空間添加一個(gè)平地的3D模型來(lái)渲染他//1.獲取捕捉到的平地錨點(diǎn)ARPlaneAnchor *planeAnchor = (ARPlaneAnchor *)anchor;//2.創(chuàng)建一個(gè)3D物體模型 （系統(tǒng)捕捉到的平地是一個(gè)不規(guī)則大小的長(zhǎng)方形，這里筆者將其變成一個(gè)長(zhǎng)方形，并且是否對(duì)平地做了一個(gè)縮放效果）//參數(shù)分別是長(zhǎng)寬高和圓角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（默認(rèn)模型是白色的，這里筆者改成紅色）plane.firstMaterial.diffuse.contents = [UIColor redColor];//4.創(chuàng)建一個(gè)基于3D物體模型的節(jié)點(diǎn)SCNNode *planeNode = [SCNNode nodeWithGeometry:plane];//5.設(shè)置節(jié)點(diǎn)的位置為捕捉到的平地的錨點(diǎn)的中心位置 SceneKit框架中節(jié)點(diǎn)的位置position是一個(gè)基于3D坐標(biāo)系的矢量坐標(biāo)SCNVector3MakeplaneNode.position =SCNVector3Make(planeAnchor.center.x, 0, planeAnchor.center.z);//self.planeNode = planeNode;[node addChildNode:planeNode];//2.當(dāng)捕捉到平地時(shí)，2s之后開(kāi)始在平地上添加一個(gè)3D模型dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{//1.創(chuàng)建一個(gè)花瓶場(chǎng)景SCNScene *scene = [SCNScene sceneNamed:@"Models.scnassets/vase/vase.scn"];//2.獲取花瓶節(jié)點(diǎn)（一個(gè)場(chǎng)景會(huì)有多個(gè)節(jié)點(diǎn)，此處我們只寫(xiě)，花瓶節(jié)點(diǎn)則默認(rèn)是場(chǎng)景子節(jié)點(diǎn)的第一個(gè)）//所有的場(chǎng)景有且只有一個(gè)根節(jié)點(diǎn)，其他所有節(jié)點(diǎn)都是根節(jié)點(diǎn)的子節(jié)點(diǎn)SCNNode *vaseNode = scene.rootNode.childNodes[0];//4.設(shè)置花瓶節(jié)點(diǎn)的位置為捕捉到的平地的位置，如果不設(shè)置，則默認(rèn)為原點(diǎn)位置，也就是相機(jī)位置vaseNode.position = SCNVector3Make(planeAnchor.center.x, 0, planeAnchor.center.z);//5.將花瓶節(jié)點(diǎn)添加到當(dāng)前屏幕中//!!!此處一定要注意：花瓶節(jié)點(diǎn)是添加到代理捕捉到的節(jié)點(diǎn)中，而不是AR試圖的根節(jié)點(diǎn)。因?yàn)椴蹲降降钠降劐^點(diǎn)是一個(gè)本地坐標(biāo)系，而不是世界坐標(biāo)系[node addChildNode:vaseNode];});} }//刷新時(shí)調(diào)用 - (void)renderer:(id <SCNSceneRenderer>)renderer willUpdateNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor {NSLog(@"刷新中"); }//更新節(jié)點(diǎn)時(shí)調(diào)用 - (void)renderer:(id <SCNSceneRenderer>)renderer didUpdateNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor {NSLog(@"節(jié)點(diǎn)更新");}//移除節(jié)點(diǎn)時(shí)調(diào)用 - (void)renderer:(id <SCNSceneRenderer>)renderer didRemoveNode:(SCNNode *)node forAnchor:(ARAnchor *)anchor {NSLog(@"節(jié)點(diǎn)移除"); }#pragma mark -ARSessionDelegate//會(huì)話位置更新（監(jiān)聽(tīng)相機(jī)的移動(dòng)），此代理方法會(huì)調(diào)用非常頻繁，只要相機(jī)移動(dòng)就會(huì)調(diào)用，如果相機(jī)移動(dòng)過(guò)快，會(huì)有一定的誤差，具體的需要強(qiáng)大的算法去優(yōu)化，筆者這里就不深入了 - (void)session:(ARSession *)session didUpdateFrame:(ARFrame *)frame {NSLog(@"相機(jī)移動(dòng)");if (self.arType != ARTypeMove) {return;}//移動(dòng)飛機(jī)if (self.planeNode) {//捕捉相機(jī)的位置，讓節(jié)點(diǎn)隨著相機(jī)移動(dòng)而移動(dòng)//根據(jù)官方文檔記錄，相機(jī)的位置參數(shù)在4X4矩陣的第三列self.planeNode.position =SCNVector3Make(frame.camera.transform.columns[3].x,frame.camera.transform.columns[3].y,frame.camera.transform.columns[3].z);}} - (void)session:(ARSession *)session didAddAnchors:(NSArray<ARAnchor*>*)anchors {NSLog(@"添加錨點(diǎn)");}- (void)session:(ARSession *)session didUpdateAnchors:(NSArray<ARAnchor*>*)anchors {NSLog(@"刷新錨點(diǎn)");}- (void)session:(ARSession *)session didRemoveAnchors:(NSArray<ARAnchor*>*)anchors {NSLog(@"移除錨點(diǎn)");}- (void)didReceiveMemoryWarning {[super didReceiveMemoryWarning];// Dispose of any resources that can be recreated. }/* #pragma mark - Navigation// In a storyboard-based application, you will often want to do a little preparation before navigation - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {// Get the new view controller using [segue destinationViewController].// Pass the selected object to the new view controller. } */@end

1.3-代碼下載地址

• ARKit從入門(mén)到精通Demo:http://download.csdn.net/detail/u013263917/9868679

• 筆者已經(jīng)將8、9、10三小節(jié)的代碼合并成一個(gè)完整的小demo，供讀者交流學(xué)習(xí)

  
  

總結(jié)

以上是生活随笔為你收集整理的ARKit从入门到精通（9）-ARKit让飞机跟着镜头飞起来的全部?jī)?nèi)容，希望文章能夠幫你解決所遇到的問(wèn)題。

如果覺(jué)得生活随笔網(wǎng)站內(nèi)容還不錯(cuò)，歡迎將生活随笔推薦給好友。