iOS，RealityKit。您将如何检查实体是否附加到 EntityAnchor答案

【问题标题】：iOS, RealityKit. How would you check if the Entity is appended to EntityAnchoriOS，RealityKit。您将如何检查实体是否附加到 EntityAnchor
【发布时间】：2021-11-23 04:34:11
【问题描述】：

我想在 Entity 不仅已加载回合也已成功附加到 AnchorEntity

时运行一些函数

现在我的实体正在异步加载。

 func addModel(to planeAnchor: AnchorEntity) {
        Entity.loadAsync(named: "SomeUSDZModel")
            .sink { completion in
                switch completion {
                case .finished:
                    print("Ok")
                case .failure(let error):
                    print(error.localizedDescription)
                }
            } receiveValue: { model in
                // Entity should be added before the animation is started.
                planeAnchor.addChild(model)
                if let walkingAnimation = model.availableAnimations.first {
                    model.playAnimation(walkingAnimation.repeat(duration: .infinity),
                                        transitionDuration: 1.25,
                                        blendLayerOffset: 0,
                                        separateAnimatedValue: false,
                                        startsPaused: false)

                }
                self.model = model
                
            }
            .store(in: &subscriptions)
            doSomething()
    }

方法 doSomething() 过早触发。我想通过一些条件检查来触发它。

【问题讨论】：

标签： swift arkit combine realitykit

【解决方案1】：

我已经设法采取了不同的方法来解决这个问题。

首先我创建了一个 AnchorEntity

let planeAnchor = AnchorEntity(
        plane: .horizontal,
        classification: .any,
        minimumBounds: [0.5,0.5]
    )

我立即将机器人添加到此锚点：

 robot = MegaRobot(anchorEntity: planeAnchor, arView: self, gameSettings: gameSettings)

此时，我将动画暂停但激活。

现在我要订阅我的 planeAnchor 上 AnimationEvents 的更改：

func observeAnchorState() {
        if let robot = robot {
            self.gameSettings.gameStatus = .planeSearching
            // 1. Subscribe to changes
            self.anchorEntitySubscribtion = self.scene.subscribe(
                to: SceneEvents.AnchoredStateChanged.self,
                on: planeAnchor) { anchored in
                    // 3. if the change is the desired one, perform extra setup
                    if anchored.isAnchored {
                        robot.robotMode()
                        robot.animationController?.resume()
                        robot.activateRobotDragging()
                        self.gameSettings.gameStatus = .positioning
                        DispatchQueue.main.async {
                            // 4. Remove subscriber if further observations are not needed
                            self.anchorEntitySubscribtion?.cancel()
                            self.anchorEntitySubscribtion = nil
                        }
                    }
                }
            // 2. add planeAnchor to the scene
            self.scene.anchors.append(planeAnchor)
        } else {
            print("Fail to load")
        }
    }

【讨论】：