let rez = 20;

let food;

let w;

let h;

​

function setup() {

  createCanvas(400, 400, WEBGL);

  w = floor(width / rez);

  h = floor(height / rez);

  frameRate(5);

  snake = new Snake();

  foodLocation();

}

​

function foodLocation() {

  let x = floor(random(w));

  let y = floor(random(h));

  food = createVector(x, y);

​

}

​

function keyPressed() {

  if (keyCode === LEFT_ARROW) {

    snake.setDir(-1, 0);

  } else if (keyCode === RIGHT_ARROW) {

    snake.setDir(1, 0);

  } else if (keyCode === DOWN_ARROW) {

    snake.setDir(0, 1);

  } else if (keyCode === UP_ARROW) {

    snake.setDir(0, -1);

  } else if (key == ' ') {

    snake.grow();

  }

​

}

​

function draw() {

  scale(rez);

  background(220);

  if (snake.eat(food)) {

    foodLocation();

  }

  snake.update();

  snake.show();

​

​

  if (snake.endGame()) {

    print("END GAME");

    background(255, 0, 0);

    noLoop();

  }

​

  noStroke();

  fill(255, 0, 0);

  rect(food.x, food.y, 1, 1);

}

class Snake {

  constructor() {

    this.body = [];

    this.body[0] = createVector(floor(w/2), floor(h/2));

    this.xdir = 0;

    this.ydir = 0;

    this.len = 0;

  }

  setDir(x, y) {

    this.xdir = x;

    this.ydir = y;

  }

  update() {

    let head = this.body[this.body.length-1].copy();

    this.body.shift();

    head.x += this.xdir;

    head.y += this.ydir;

    this.body.push(head);

  }

  grow() {

    let head = this.body[this.body.length-1].copy();

    this.len++;

    this.body.push(head);

  }

  endGame() {

    let x = this.body[this.body.length-1].x;

    let y = this.body[this.body.length-1].y;

    if(x > w-1 || x < 0 || y > h-1 || y < 0) {

       return true;

    }

    for(let i = 0; i < this.body.length-1; i++) {

        let part = this.body[i];

      if(part.x == x && part.y == y) {

        return true;

      }

    }

    return false;

  }

  eat(pos) {

    let x = this.body[this.body.length-1].x;

    let y = this.body[this.body.length-1].y;

    if(x == pos.x && y == pos.y) {

      this.grow();

      return true;

    }

    return false;

  }

  show() {

    for(let i = 0; i < this.body.length; i++) {

        fill(0);

      noStroke();

      rect(this.body[i].x, this.body[i].y, 1, 1)

    }

  }

}

​

​

​

​