snake game

Study/JavaScript

snake game

더 멋진 세상을 꿈꾸는 개발자 2020. 5. 19. 14:05

//html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link
      href="https://fonts.googleapis.com/css2?family=Pangolin&display=swap"
      rel="stylesheet"
    />
    <title>snake Game</title>
  </head>
  <body>
    <canvas id="snake" width="608" height="608"></canvas>
    <script src="index.js"></script>
  </body>
</html>

js코드는 아래와 같다.

const cvs = document.getElementById("snake");
const ctx = cvs.getContext("2d");

//create the unit
let box = 32;

//load images
const ground = new Image();
ground.src = "images/ground.png";

const foodImg = new Image();
foodImg.src = "images/food.png";

//load audio files
const dead = new Audio();
const eat = new Audio();

dead.src = "audios/gameover.mp3";
eat.src = "audios/eat.mp3";

//create the snake

let snake = [];
snake[0] = {
  x: 9 * box,
  y: 10 * box,
};

//create the food

let food = {
  x: Math.floor(Math.random() * 17 + 1) * box,
  y: Math.floor(Math.random() * 15 + 3) * box,
};

//create the score var

let score = 0;

//control the snake

let d;

document.addEventListener("keydown", direction);

function direction(event) {
  if (event.keyCode == 37 && d != "RIGHT") {
    d = "LEFT";
  } else if (event.keyCode == 38 && d != "DOWN") {
    d = "UP";
  } else if (event.keyCode == 39 && d != "LEFT") {
    d = "RIGHT";
  } else if (event.keyCode == 40 && d != "UP") {
    d = "DOWN";
  }
}

//check collision function
function collision(head, array) {
  for (let i = 0; i < array.length; i++) {
    if (head.x == array[i].x && head.y == array[i].y) {
      return true;
    }
  }
  return false;
}

//draw everyting to the canvas

function draw() {
  ctx.drawImage(ground, 0, 0);
  for (let i = 0; i < snake.length; i++) {
    ctx.fillStyle = i == 0 ? "green" : "white";
    ctx.fillRect(snake[i].x, snake[i].y, box, box);

    ctx.strokeStyle = "red";
    ctx.strokeRect(snake[i].x, snake[i].y, box, box);
  }
  ctx.drawImage(foodImg, food.x, food.y);

  //old head position
  let snakeX = snake[0].x;
  let snakeY = snake[0].y;

  //which direction
  if (d == "LEFT") snakeX -= box;
  if (d == "UP") snakeY -= box;
  if (d == "RIGHT") snakeX += box;
  if (d == "DOWN") snakeY += box;

  //if the snake eats the food
  if (snakeX == food.x && snakeY == food.y) {
    score++;
    eat.play();
    food = {
      x: Math.floor(Math.random() * 17 + 1) * box,
      y: Math.floor(Math.random() * 15 + 3) * box,
    };
    // we don't remove the tail
  } else {
    //remeove the tail
    snake.pop();
  }

  //add new head

  let newHead = {
    x: snakeX,
    y: snakeY,
  };

  //game over
  if (
    snakeX < box ||
    snakeX > 17 * box ||
    snakeY < 3 * box ||
    snakeY > 17 * box ||
    collision(newHead, snake)
  ) {
    clearInterval(game);
    dead.play();
  }

  snake.unshift(newHead);

  ctx.fillStyle = "white";
  ctx.font = "45px Pangolin";
  ctx.fillText(score, 2 * box, 1.6 * box);
}

// call draw function every 100 ms

let game = setInterval(draw, 100);

출처 : https://www.youtube.com/watch?v=9TcU2C1AACw&t=81s

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