Question

我一直绞尽脑汁，在这里搜索并试图找出如何在屏幕上生成随机位置以产生一个圆圈。我希望有人可以帮助我，因为我完全难过。基本上，我试图创建一个在用户触摸时始终在屏幕上随机出现的形状。

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        let screenSize: CGRect = UIScreen.mainScreen().bounds
        let screenHeight = screenSize.height
        let screenWidth = screenSize.width

        let currentBall = SKShapeNode(circleOfRadius: 100)
        currentBall.position = CGPointMake(CGFloat(arc4random_uniform(UInt32(Float(screenWidth)))), CGFloat(arc4random_uniform(UInt32(Float(screenHeight)))))

        self.removeAllChildren()
        self.addChild(currentBall)
}

如果你们都需要更多我的代码，那就再也没有了。但是，谢谢你给予的任何帮助！（重申一下，这段代码很有用......但是大多数产生的球似乎都会在屏幕外产生）

Answer 1

问题是你的场景比屏幕边界大

let viewMidX = view!.bounds.midX
let viewMidY = view!.bounds.midY
print(viewMidX)
print(viewMidY)

let sceneHeight = view!.scene!.frame.height
let sceneWidth = view!.scene!.frame.width
print(sceneWidth)
print(sceneHeight)

let currentBall = SKShapeNode(circleOfRadius: 100)
currentBall.fillColor = UIColor.greenColor()

let xPosition = view!.scene!.frame.midX - viewMidX + CGFloat(arc4random_uniform(UInt32(viewMidX*2)))
let yPosition = view!.scene!.frame.midY - viewMidY + CGFloat(arc4random_uniform(UInt32(viewMidY*2)))
print(xPosition)
print(yPosition)

currentBall.position = CGPointMake(xPosition,yPosition)
view?.scene?.addChild(currentBall)

self.removeAllChildren()
self.addChild(currentBall)

Answer 2

首先：确定有效的区域。它可能不是超级视图的框架，因为也许球（让我们称之为ballView）可能会被切断。该区域可能是（伪代码）：

CGSize( Width of the superview - width of ballView , Height of the superview - height of ballView)

获得该尺寸后，只需将其放在屏幕上origin 0,0。

其次：现在你有一系列有效的坐标。只需使用随机函数（如您正在使用的函数）来选择其中一个。

使用以下内容创建一个swift文件：

extension Int
{
    static func random(range: Range<Int>) -> Int
    {
        var offset = 0

        if range.startIndex < 0   // allow negative ranges
        {
            offset = abs(range.startIndex)
        }

        let mini = UInt32(range.startIndex + offset)
        let maxi = UInt32(range.endIndex   + offset)

        return Int(mini + arc4random_uniform(maxi - mini)) - offset
    }
}

现在您可以按如下方式指定随机数：

Int.random(1...1000) //generate a random number integer somewhere from 1 to 1000.

现在可以使用此功能生成x和y坐标的值。

Answer 3

给出以下随机生成器：

public extension CGFloat {
    public static var random: CGFloat { return CGFloat(arc4random()) / CGFloat(UInt32.max) }

    public static func random(between x: CGFloat, and y: CGFloat) -> CGFloat {
        let (start, end) = x < y ? (x, y) : (y, x)
        return start + CGFloat.random * (end - start)
    }
}

public extension CGRect {
    public var randomPoint: CGPoint {
        var point = CGPoint()
        point.x = CGFloat.random(between: origin.x, and: origin.x + width)
        point.y = CGFloat.random(between: origin.y, and: origin.y + height)
        return point
    }
}

您可以将以下内容粘贴到游乐场：

import XCPlayground
import SpriteKit

let view = SKView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
XCPShowView("game", view)

let scene = SKScene(size: view.frame.size)
view.presentScene(scene)

let wait = SKAction.waitForDuration(0.5)
let popIn = SKAction.scaleTo(1, duration: 0.25)
let popOut = SKAction.scaleTo(0, duration: 0.25)
let remove = SKAction.removeFromParent()

let popInAndOut = SKAction.sequence([popIn, wait, popOut, remove])

let addBall = SKAction.runBlock { [unowned scene] in
    let ballRadius: CGFloat = 25
    let ball = SKShapeNode(circleOfRadius: ballRadius)
    var popInArea = scene.frame
    popInArea.inset(dx: ballRadius, dy: ballRadius)
    ball.position = popInArea.randomPoint
    ball.xScale = 0
    ball.yScale = 0
    ball.runAction(popInAndOut)
    scene.addChild(ball)
}

scene.runAction(SKAction.repeatActionForever(SKAction.sequence([addBall, wait])))

（只需确保也粘贴随机生成器，或将它们复制到游乐场Sources，以及打开助理编辑器以便您可以看到动画。）

在屏幕上的随机点产生一个圆圈

3 个答案: