ساخت بازی Snake در SwiftUI | به زبان ساده

1enum direction {
2    case up, down, left, right
3}

1@State var startPos : CGPoint = .zero // the start poisition of our swipe
2@State var isStarted = true // did the user started the swipe?
3@State var gameOver = false // for ending the game when the snake hits the screen borders
4@State var dir = direction.down // the direction the snake is going to take
5@State var posArray = [CGPoint(x: 0, y: 0)] // array of the snake's body positions
6@State var foodPos = CGPoint(x: 0, y: 0) // the position of the food
7let snakeSize : CGFloat = 10 // width and height of the snake 
8let timer = Timer.publish(every: 0.1, on: .main, in: .common).autoconnect() // to updates the snake position every 0.1 second

1    var body: some View {
2        ZStack {
3            Color.pink.opacity(0.3)
4            ZStack {
5                ForEach (0..<posArray.count, id: \.self) { index in
6                    Rectangle()
7                        .frame(width: self.snakeSize, height: self.snakeSize)
8                        .position(self.posArray[index])
9                }
10                Rectangle()
11                    .fill(Color.red)
12                    .frame(width: snakeSize, height: snakeSize)
13                    .position(foodPos)
14            }
15            
16            if self.gameOver {
17                Text("Game Over")
18            }
19        }
20    }

1let minX = UIScreen.main.bounds.minX
2let maxX = UIScreen.main.bounds.maxX
3let minY = UIScreen.main.bounds.minY
4let maxY = UIScreen.main.bounds.maxY
5
6func changeRectPos() -> CGPoint {
7        let rows = Int(maxX/snakeSize)
8        let cols = Int(maxY/snakeSize)
9        
10        let randomX = Int.random(in: 1..<rows) * Int(snakeSize)
11        let randomY = Int.random(in: 1..<cols) * Int(snakeSize)
12        
13        return CGPoint(x: randomX, y: randomY)
14    }

1.onAppear() {
2     self.foodPos = self.changeRectPos()
3     self.posArray[0] = self.changeRectPos()
4}

1    func changeDirection () {
2        if self.posArray[0].x < minX || self.posArray[0].x > maxX && !gameOver{
3            gameOver.toggle()
4        }
5        else if self.posArray[0].y < minY || self.posArray[0].y > maxY  && !gameOver {
6            gameOver.toggle()
7        }
8        var prev = posArray[0]
9        if dir == .down {
10            self.posArray[0].y += snakeSize
11        } else if dir == .up {
12            self.posArray[0].y -= snakeSize
13        } else if dir == .left {
14            self.posArray[0].x += snakeSize
15        } else {
16            self.posArray[0].x -= snakeSize
17        }
18        
19        for index in 1..<posArray.count {
20            let current = posArray[index]
21            posArray[index] = prev
22            prev = current
23        }
24    }

1        .gesture(DragGesture()
2        .onChanged { gesture in
3            if self.isStarted {
4                self.startPos = gesture.location
5                self.isStarted.toggle()
6            }
7        }
8        .onEnded {  gesture in
9            let xDist =  abs(gesture.location.x - self.startPos.x)
10            let yDist =  abs(gesture.location.y - self.startPos.y)
11            if self.startPos.y <  gesture.location.y && yDist > xDist {
12                self.dir = direction.down
13            }
14            else if self.startPos.y >  gesture.location.y && yDist > xDist {
15                self.dir = direction.up
16            }
17            else if self.startPos.x > gesture.location.x && yDist < xDist {
18                self.dir = direction.right
19            }
20            else if self.startPos.x < gesture.location.x && yDist < xDist {
21                self.dir = direction.left
22            }
23            self.isStarted.toggle()
24            }
25        )

1       .onReceive(timer) { (_) in
2         if !self.gameOver {
3              self.changeDirection()
4              if self.posArray[0] == self.foodPos {
5                   self.posArray.append(self.posArray[0])
6                    self.foodPos = self.changeRectPos()
7               }
8         }
9       }
10        .edgesIgnoringSafeArea(.all)