SwiftのGameplayKitでAIに追いかける、避ける、逃げる処理を追加するには：ゲームの「敵」キャラで分かる「人工知能」の作り方（2）（1/4 ページ）

class GameScene: SKScene {
    // 省略
 
    override func didMove(to view: SKView) {
        player.fillColor = UIColor(red: 0.93, green: 0.96, blue: 0.00, alpha: 1.0)
        addChild(player)
 
        createObstacles() // 今回追加
        setCreateEnemyTimer()
        physicsWorld.gravity = CGVector()
    }
 
    // ここから今回追加
    func createObstacles() {
        guard let viewFrame = view?.frame else {
            return
        }
 
        var obstacleNodes = [SKShapeNode]()
        while obstacleNodes.count < 5 {
            let point = CGPoint(
                x: CGFloat(arc4random_uniform(UInt32(viewFrame.width))) - viewFrame.width / 2,
                y: CGFloat(arc4random_uniform(UInt32(viewFrame.height))) - viewFrame.height / 2)
            let radius = CGFloat(arc4random_uniform(50) + 50)
 
            // 障害物かPlayerが衝突していたら設置しない
            let isObstacleOverlapped = obstacleNodes.contains {
                let dx = (point.x - $0.position.x)
                let dy = (point.y - $0.position.y)
                if sqrt(dx*dx + dy*dy) < $0.frame.width + radius {
                    return true
                }
                return false
            }
            let dx = point.x - player.position.x
            let dy = point.y - player.position.y
            let isPlayerOverlapped = sqrt(dx*dx + dy*dy) < radius + player.frame.width
            if isObstacleOverlapped || isPlayerOverlapped {
                continue
            }
 
            let obstacleNode = SKShapeNode(circleOfRadius: CGFloat(radius))
            obstacleNode.fillColor = UIColor(red: 0.7, green: 0.7, blue: 0.7, alpha: 1.0)
            obstacleNode.position = point
            obstacleNode.physicsBody = SKPhysicsBody(circleOfRadius: CGFloat(radius))
            obstacleNode.physicsBody?.pinned = true
            addChild(obstacleNode)
            obstacleNodes.append(obstacleNode)
        }
    }
    // ここまで今回追加
 
    // 省略
}

class GameScene: SKScene {
    // 省略
 
    override func didMove(to view: SKView) {
        player.fillColor = UIColor(red: 0.93, green: 0.96, blue: 0.00, alpha: 1.0)
        player.physicsBody = SKPhysicsBody(circleOfRadius: 10) // 今回追加
        addChild(player)
 
        createObstacles()
        setCreateEnemyTimer()
        physicsWorld.gravity = CGVector()
    }
    // 省略
}