initial

snakegame/Snake.swift

@@ -0,0 +1,66 @@
+//
+//  Snake.swift
+//  snakegame
+//
+//  Created by Nik Rodionov on 23.06.2020.
+//  Copyright © 2020 nrodionov. All rights reserved.
+//
+
+import SpriteKit
+
+class Snake: SKShapeNode {
+    private var body = [SnakeBodyPart]()
+    private let moveSpeed: CGFloat = 125.0
+    private var angle: CGFloat = 0.0
+    
+    convenience init(position: CGPoint) {
+        self.init()
+        
+        let head = SnakeHead(position: position)
+        body.append(head)
+        
+        addChild(head)
+    }
+    
+    func addBodyPart() {
+        let newBodyPart = SnakeBodyPart(position: body[0].position)
+        body.append(newBodyPart)
+        
+        addChild(newBodyPart)
+    }
+    
+    func moveClockWise() {
+        angle += CGFloat.pi / 2
+    }
+    
+    func moveCounterClockWise() {
+        angle -= CGFloat.pi / 2
+    }
+    
+    func move() {
+        moveHead(body[0])
+        
+        for i in 1..<body.count {
+            let previous = body[i - 1]
+            let current = body[i]
+            
+            moveBodyPart(current, previous: previous)
+        }
+    }
+    
+    private func moveHead(_ head: SnakeBodyPart) {
+        let dx = moveSpeed * sin(angle)
+        let dy = moveSpeed * cos(angle)
+        
+        let nextPostion = CGPoint(x: head.position.x + dx, y: head.position.y + dy)
+        
+        let moveAction = SKAction.move(to: nextPostion, duration: 1.0)
+        head.run(moveAction)
+    }
+    
+    private func moveBodyPart(_ part: SnakeBodyPart, previous: SnakeBodyPart ) {
+        let moveAction = SKAction.move(to: previous.position, duration: 0.1)
+        
+        part.run(moveAction)
+    }
+}