iOS SpriteKit 与屏幕边缘冲突不起作用

Question

>我试图在SKShapeNode实例和屏幕边缘之间创建冲突，但由于某种原因，ShapeNode仍然超出了屏幕的限制。我已经实现了我认为应该处理碰撞的代码，但我是 SpriteKit 的新手，所以我不完全确定。下面是一段代码：

//
//  GameScene.swift
//  SpriteKitTest
//
//  Created by 580380 on 3/10/16.
//  Copyright (c) 2016 580380. All rights reserved.
//
import SpriteKit
import UIKit
import CoreMotion
class GameScene: SKScene {
    //MARK: - Global variables
    let motionManager = CMMotionManager()
    var circleNode = SKShapeNode()
    var destX : CGFloat = 0.0
    var destY : CGFloat = 0.0
    enum Collision :UInt32 {
        case ball = 1
        case wall = 2
    }
    //MARK: - Sprite kit functionality
    override func didMoveToView(view: SKView) {
        backgroundColor = UIColor.whiteColor()
        createCircleNode()
        moveCircleNode()
        self.addChild(circleNode)
    }
    //Setup and configuring the SKShapeNode object
    private func createCircleNode() {
        circleNode.path = UIBezierPath(arcCenter: CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame)), radius: 20, startAngle: 0, endAngle: CGFloat(2*M_PI), clockwise: true).CGPath
        circleNode.fillColor = UIColor.redColor()
        circleNode.strokeColor = UIColor.blueColor()
        circleNode.lineWidth = 1
    }
    private func moveCircleNode() {
        circleNode.physicsBody = SKPhysicsBody()
        circleNode.physicsBody?.dynamic = true
        circleNode.physicsBody?.affectedByGravity = false
        if motionManager.accelerometerAvailable {
            motionManager.accelerometerUpdateInterval = 0.1
            motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.mainQueue(), withHandler: { (data, error) -> Void in
                self.destX = self.circleNode.position.x + CGFloat(data!.acceleration.x*100)
                self.destY = self.circleNode.position.y + CGFloat(data!.acceleration.y*200)
            })
        }
        self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
        self.physicsBody!.dynamic = true
        self.physicsBody!.affectedByGravity = false
        self.physicsBody!.categoryBitMask = Collision.wall.rawValue
        self.physicsBody!.collisionBitMask = Collision.ball.rawValue
    }
    override func update(currentTime: NSTimeInterval) {
        let destXAction = SKAction.moveToX(destX, duration: 0.1)
        let destYAction = SKAction.moveToY(destY, duration: 0.1)
        self.circleNode.runAction(destXAction)
        self.circleNode.runAction(destYAction)
    }
}

知道我可能在哪里出错吗？

Answer 1

这里的主要问题是游戏场景从未真正设置其大小。

在GameViewController将行scene.size = skView.bounds.size添加到 let skView = self.view as! SKView 下。

这将正确设置场景的大小，所以现在你的球应该与屏幕边缘碰撞。但是，当您设置circleNode路径时，您实现它的方式将圆圈偏移了屏幕大小的一半。

如果您希望圆圈出现在屏幕中间，更好的解决方案是 circleNode = SKShapeNode(circleOfRadius: 20) 而不是 circleNode.path = UIBezierPath(arcCenter: CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame)), radius: 20, startAngle: 0, endAngle: CGFloat(2*M_PI), clockwise: true).CGPath .然后将其设置为位于中心，并带有 circleNode.position = CGPointMake(frame.width/2, frame.height/2) .

这应该可以解决您的整体问题，但是您可能会注意到球可能会从屏幕边缘消失。要解决此问题，请将更新方法更改为如下所示

func clamp(value: CGFloat, min: CGFloat, max: CGFloat) -> CGFloat {
    if value > max {
        return max
    }
    if value < min {
        return min
    }
    return value
}

override func update(currentTime: NSTimeInterval) {
    let ballRadius: CGFloat = 10
    destX = clamp(destX, min: ballRadius, max: frame.width - ballRadius)
    destY = clamp(destY, min: ballRadius, max: frame.height - ballRadius)
    let destXAction = SKAction.moveToX(destX, duration: 0.1)
    let destYAction = SKAction.moveToY(destY, duration: 0.1)
    self.circleNode.runAction(destXAction)
    self.circleNode.runAction(destYAction)
}

这将使球永远不要试图超出屏幕的范围。我还建议添加circleNode.physicsBody?.usesPreciseCollisionDetection = true以便您的碰撞更准确。