我正在创建一个小游戏并学习Spritekit物理。我有一个SKScene，我在screne的边缘放置了4个边框（左，右，上，下。制作正方形）。 Beetwin他们我有一个圆圈SKShapeNode，我用速度移动它（dx：200，dy：200）。我希望我的shapenode永远地从现实世界的边界反弹。因此，如果它以速度（dx：200，dy：200）移动到右边界，则由X轴反弹，从上边界移动Y轴。 我想如何做到这一点，我以为我得到了它。我创建了一些代码，但在一系列反弹后它无法正常工作。
public var redLaserTexVert = SKTexture()
public var redCircle = SKShapeNode()
public var redCircleObject = SKNode()
public var redLaserTex = SKTexture()
public var redLaser = SKSpriteNode()
public var redLaserObject = SKNode()
public var redLaser2 = SKSpriteNode()
public var redLaserObject2 = SKNode()
public var redLaser3 = SKSpriteNode()
public var redLaserObject3 = SKNode()
public var redLaser4 = SKSpriteNode()
public var redLaserObject4 = SKNode()
public var greenCircle = SKShapeNode()
public var greenCircleObject = SKNode()
public var dx = Int()
public var dy = Int()
public var plusX = 200
public var minusX = -200
public var plusY = 200
public var minusY = -200
struct collision {
static let circleBody: UInt32 = 0x1 << 0
static let redLaser1: UInt32 = 0x1 << 1
static let redLaser2: UInt32 = 0x1 << 2
static let redLaser3: UInt32 = 0x1 << 3
static let redLaser4: UInt32 = 0x1 << 4
static let greenCircle: UInt32 = 0x1 << 5
}
class GameScene: SKScene, SKPhysicsContactDelegate {
override func didMove(to view: SKView) {
self.physicsWorld.contactDelegate = self
self.backgroundColor = UIColor.white
greenCircle = SKShapeNode.init(circleOfRadius: self.frame.width/9)
greenCircle.position = CGPoint(x: 100, y: 100)
greenCircle.fillColor = UIColor.green
greenCircle.physicsBody = SKPhysicsBody(circleOfRadius: self.frame.width/9)
greenCircle.physicsBody?.affectedByGravity = false
greenCircle.physicsBody?.isDynamic = true
greenCircleObject.physicsBody?.categoryBitMask = collision.greenCircle
greenCircle.physicsBody?.contactTestBitMask = collision.redLaser1 | collision.redLaser2 | collision.redLaser3 | collision.redLaser4
greenCircle.physicsBody?.collisionBitMask = collision.redLaser1 | collision.redLaser2 | collision.redLaser3 | collision.redLaser4
greenCircleObject.addChild(greenCircle)
self.addChild(greenCircleObject)
greenCircle.name = "greenCircle"
dx = plusX
dy = plusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
redLaserTex = SKTexture(imageNamed: "redLaserRay")
redLaserTexVert = SKTexture(imageNamed: "redLaserRayVert")
redLaser = SKSpriteNode(texture: redLaserTex)
redLaser.size = CGSize(width: self.frame.width, height: self.frame.height/12)
redLaser.position = CGPoint(x: self.frame.midX, y: self.frame.minY+10)
redLaser.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: self.frame.width, height: 10))
redLaser.physicsBody?.affectedByGravity = false
redLaser.physicsBody?.isDynamic = false
redLaser.physicsBody?.categoryBitMask = collision.redLaser1
redLaser.physicsBody?.contactTestBitMask = collision.greenCircle
redLaser.physicsBody?.collisionBitMask = collision.greenCircle
redLaserObject.addChild(redLaser)
self.addChild(redLaserObject)
redLaser.name = "leftLr"
redLaser2 = SKSpriteNode(texture: redLaserTex)
redLaser2.size = CGSize(width: self.frame.width, height: self.frame.height/12)
redLaser2.position = CGPoint(x: self.frame.midX, y: self.frame.maxY-10)
redLaser2.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: self.frame.width, height: 10))
redLaser2.physicsBody?.affectedByGravity = false
redLaser2.physicsBody?.isDynamic = false
redLaser2.physicsBody?.categoryBitMask = collision.redLaser2
redLaser2.physicsBody?.contactTestBitMask = collision.greenCircle
redLaser2.physicsBody?.collisionBitMask = collision.greenCircle
redLaserObject2.addChild(redLaser2)
redLaser2.name = "upLr"
self.addChild(redLaserObject2)
redLaser3 = SKSpriteNode(texture: redLaserTexVert)
redLaser3.size = CGSize(width: self.frame.width/6, height: self.frame.height)
redLaser3.position = CGPoint(x: self.frame.minX+10, y: self.frame.midY)
redLaser3.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: 10, height: self.frame.height))
redLaser3.physicsBody?.affectedByGravity = false
redLaser3.physicsBody?.isDynamic = false
redLaser3.physicsBody?.categoryBitMask = collision.redLaser3
redLaser3.physicsBody?.contactTestBitMask = collision.greenCircle
redLaser3.physicsBody?.collisionBitMask = collision.greenCircle
redLaserObject3.addChild(redLaser3)
redLaser3.name = "bottomLr"
self.addChild(redLaserObject3)
redLaser4 = SKSpriteNode(texture: redLaserTexVert)
redLaser4.size = CGSize(width: self.frame.width/6, height: self.frame.height)
redLaser4.position = CGPoint(x: self.frame.maxX-10, y: self.frame.midY)
redLaser4.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: 10, height: self.frame.height))
redLaser4.physicsBody?.affectedByGravity = false
redLaser4.physicsBody?.isDynamic = false
redLaser4.physicsBody?.categoryBitMask = collision.redLaser4
redLaser4.physicsBody?.contactTestBitMask = collision.greenCircle
redLaser4.physicsBody?.collisionBitMask = collision.greenCircle
redLaserObject4.addChild(redLaser4)
redLaser4.name = "rightLr"
self.addChild(redLaserObject4)
}
func didBegin(_ contact: SKPhysicsContact) {
var firstBody = SKPhysicsBody()
var secondBody = SKPhysicsBody()
if contact.bodyA.node?.name == "greenCircle" {
firstBody = contact.bodyA
secondBody = contact.bodyB }
else {
firstBody = contact.bodyB
secondBody = contact.bodyA }
if firstBody.node?.name == "greenCircle" && secondBody.node?.name == "rightLr" {
if dx == plusX && dy == plusY {
dx = minusX
dy = plusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
if dx == plusX && dy == minusY {
dx = minusX
dy = minusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
}
if firstBody.node?.name == "greenCircle" && secondBody.node?.name == "upLr" {
if dx == minusX && dy == plusY {
dx = minusX
dy = minusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
if dx == plusX && dy == plusY {
dx = plusX
dy = minusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
}
if firstBody.node?.name == "greenCircle" && secondBody.node?.name == "bottomLr" {
if dx == plusX && dy == minusY {
dx = plusX
dy = plusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
if dx == minusX && dy == minusY {
dx = minusX
dy = plusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
}
if firstBody.node?.name == "greenCircle" && secondBody.node?.name == "leftLr" {
if dx == minusX && dy == minusY {
dx = plusX
dy = minusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
if dx == minusX && dy == plusY {
dx = plusX
dy = plusY
greenCircle.physicsBody?.velocity = CGVector(dx: dx, dy: dy)
}
}
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches { self.touchUp(atPoint: t.location(in: self)) }
}
override func update(_ currentTime: TimeInterval) {
// greenCircle.physicsBody?.velocity = CGVector(dx: 200, dy: 200)
}
}