知识点

• 通过颜色和尺寸生成精灵node
• 若隐若现亮光动画
• parentNode添加subNode，position布局
• 捕捉两物理碰撞检测等

开始干

代码很简单，如下：

import SpriteKit

// 建议用位移来设置，当碰撞node很多时，设置的时候用|运算来支持多种选择
let categoryRock: UInt32 = 0x1 << 1
let categoryShip: UInt32 = 0x1 << 2

class HelloShipSceneNew: SKScene {
    override func didMove(to view: SKView) {
        backgroundColor = .black
        scaleMode = .aspectFit
        
        addChild(shipNode())
        
        generateRock()
    }
    
    func shipNode() -> SKSpriteNode {
        // 通过颜色和尺寸创建node
        let shipNode = SKSpriteNode(color: .green, size: CGSize(width: 100, height: 50))
        shipNode.position = view!.center
        shipNode.physicsBody = SKPhysicsBody(rectangleOf: shipNode.size)
        shipNode.physicsBody?.categoryBitMask = categoryShip
        shipNode.physicsBody?.isDynamic = false
        shipNode.name = "ship"
        
        addShipLights(shipNode)
        
        return shipNode
    }
    
    // 给飞船山下添加 白光
    func addShipLights(_ shipNode: SKSpriteNode) {
        let shipLightTop = SKSpriteNode(color: .white, size: CGSize(width: 50, height: 2))
        // shipNode父节点上布局shipLightTop子节点
        shipLightTop.position = CGPoint(x: 0, y: 30)
        shipNode.addChild(shipLightTop)
        
        let shipLightBottom = SKSpriteNode(color: .white, size: CGSize(width: 50, height: 2))
        shipLightBottom.position = CGPoint(x: 0, y: -30)
        shipNode.addChild(shipLightBottom)
        
        // 若隐若现动画
        let fadeInAction = SKAction.fadeIn(withDuration: 0.15)
        let fadeOutAction = SKAction.fadeOut(withDuration: 0.15)
        let waitAction = SKAction.wait(forDuration: 0.1)
        shipLightTop.run(SKAction.sequence([fadeInAction, waitAction, fadeOutAction]))
        shipLightBottom.run(SKAction.sequence([fadeInAction, waitAction, fadeOutAction]))
    }
    
    func rockNode() {
        let rockNode = SKSpriteNode(color: .white, size: CGSize(width: 20, height: 20))
        let randomX = CGFloat(arc4random_uniform(UInt32(frame.width*0.8)))
        rockNode.position = CGPoint(x: randomX, y: frame.height)
        rockNode.physicsBody = SKPhysicsBody(rectangleOf: rockNode.size)
        rockNode.physicsBody?.usesPreciseCollisionDetection = true
        rockNode.physicsBody?.categoryBitMask = categoryRock
        rockNode.name = "rock"
        
        addChild(rockNode)
    }
    
    // 重复不断产生rock
    func generateRock() {
        let generateAction = SKAction.run{
            self.rockNode()
        }
        let waitAction = SKAction.wait(forDuration: 0.15)
        run(SKAction.repeatForever(SKAction.sequence([generateAction,waitAction])))
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        // 移动飞船
        guard let touch = touches.first else {
            return
        }
        if let ship = childNode(withName: "ship")  {
            let moveAction = SKAction.move(to: touch.location(in: self), duration: 0.5)
            ship.run(moveAction)
        }
    }
    
    override func didSimulatePhysics() {
        // 当rock掉到屏幕外，将其移除。
        enumerateChildNodes(withName: "rock") { (node, _) in
            if node.position.y < 0 {
                node.removeFromParent()
            }
        }
    }
}

// 碰撞检测回调
extension HelloShipScene: SKPhysicsContactDelegate {
    func didBegin(_ contact: SKPhysicsContact) {
        let bodyA: SKPhysicsBody
        let bodyB: SKPhysicsBody
        if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
            bodyA = contact.bodyA
            bodyB = contact.bodyB
        }else {
            bodyA = contact.bodyB
            bodyB = contact.bodyA
        }
        
        if bodyA.categoryBitMask == categoryRock && bodyB.categoryBitMask == categoryShip {
            print("石头和飞船碰撞💥")
        }
    }
}

此时运行效果：

• 问题一
  既然没看见亮光，要么node没加上，要么是动画有问题，再仔细看代码，确实动画有问题。就执行了一次，那么短怎么看的到。而且已经有消失和出现切换 没必要再加个wait动画了。addShipLights方法里休改成如下代码即可。

// 若隐若现动画
        let fadeInAction = SKAction.fadeIn(withDuration: 0.25)
        let fadeOutAction = SKAction.fadeOut(withDuration: 0.25)
//        let waitAction = SKAction.wait(forDuration: 0.1)
        shipLightTop.run(SKAction.repeatForever((SKAction.sequence([fadeInAction, fadeOutAction]))))
        shipLightBottom.run(SKAction.repeatForever((SKAction.sequence([fadeInAction, fadeOutAction]))))

• 问题二
  问题二很简单，shipNode都禁用物理体属性啦，当与其它物理体碰撞时肯定是不会走回调的，改成true即可，但我们这里先不改

shipNode.physicsBody?.isDynamic = true

最终效果

改后来看下最终效果，是不是有亮亮的光了。