swift – 获取特定区域中的节点列表？

这就是我现在正在尝试的事情：

import SpriteKit
import CoreMotion

class GameScene: SKScene,SKPhysicsContactDelegate
{
var player = SKShapeNode()
var world = SKShapeNode()
var rShape = SKShapeNode()

override func didMoveToView(view: SKView) {
    self.physicsWorld.contactDelegate = self
    self.scaleMode = SKSceneScaleMode.AspectFit
    self.size = view.bounds.size

    // Add world
    world = SKShapeNode(rectOfSize: view.bounds.size)
    world.physicsBody = SKPhysicsBody(edgeLoopFromPath: world.path)
    world.position = CGPointMake(self.frame.size.width/2,self.frame.size.height/2) // Move camera
    self.addChild(world)

    // Add player
    player = SKShapeNode(rectOfSize: CGSize(width: 25,height: 25))
    player.physicsBody = SKPhysicsBody(rectangleOfSize: player.frame.size)
    player.physicsBody.dynamic = false
    player.strokeColor = SKColor.blueColor()
    player.fillColor = SKColor.blueColor()
    player.position = CGPointMake(90,-50)
    world.addChild(player)
    }


override func update(currentTime: CFTimeInterval) {
    // Define rect position and size (area that will be evaluated for bodies)
    var r : CGRect = CGRect(x: 200,y: 200,width: 25,height: 25)

    // Show rect for debug
    rShape.removeFromParent()
    rShape = SKShapeNode(rect: r)
    rShape.strokeColor = SKColor.redColor()
    self.addChild(rShape)

    // Evaluate rect
    rShape.fillColor = SKColor.clearColor()
    self.physicsWorld.enumerateBodiesInRect(r) {
        (body: SKPhysicsBody!,stop: UnsafePointer<ObjCBool>) in
         self.rShape.fillColor = SKColor.redColor() // Paint the area blue if it detects a node
         }
    }
}

此代码应在屏幕上显示已评估的rect和ray(用于调试目的),如果它们与播放器节点联系,则将其绘制为红色.但是你可以在屏幕截图中看到当玩家离它25px或更远时它变成红色,就像绘图有点偏离,或者小于被评估的实际区域.您可以将其粘贴到项目中以复制问题.

这可能是因为这只是测试版,还是我做错了什么？