how to make javascript snake game - Programming Geek Programming Geek: how to make javascript snake game

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Wednesday 29 November 2017

how to make javascript snake game

javascript snake code
javascript snake code - torok-technology

Hello everybody, today we have amazing explanation about javascript snake game and how to make a javascript snake game, also I will put the full javascript snake code inside this article for everyone, wants to learn how to make snake game with javascript programming language, its very useful for practicing on what you had learned, so let us start.


javascript snake code

firstly, you should create three files, the first file for HTML code, the second file for CSS code and the third file for javascript code, the first file will include importing CSS, javascript, a title and canvas element, also you will give the canvas id, so your HTML file will be like this:




<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" href="./snake.css">
</head>
<body>
    <canvas id="stage"></canvas>
    <script src="./snake.js"></script>
</body>
</html>


then after creating HTML file, you should create CSS file and just make a pretty style for the body and canvas element, so the style will be like this:



body {
  text-align:center;
  font-family: helvetica;
}
canvas {
  border: 2px solid rgb(151, 149, 149);
  height: 400px;
  width:520px;
}


then you maybe create the javascript file and put this code into the javascript file


/**
 * Namespace
 */
var Game      = Game      || {};
var Keyboard  = Keyboard  || {}; 
var Component = Component || {};

/**
 * Keyboard Map
 */
Keyboard.Keymap = {
  37: 'left',
  38: 'up',
  39: 'right',
  40: 'down'
};

/**
 * Keyboard Events
 */
Keyboard.ControllerEvents = function() {
  
  // Setts
  var self      = this;
  this.pressKey = null;
  this.keymap   = Keyboard.Keymap;
  
  // Keydown Event
  document.onkeydown = function(event) {
    self.pressKey = event.which;
  };
  
  // Get Key
  this.getKey = function() {
    return this.keymap[this.pressKey];
  };
};

/**
 * Game Component Stage
 */
Component.Stage = function(canvas, conf) {  
  
  // Sets
  this.keyEvent  = new Keyboard.ControllerEvents();
  this.width     = canvas.width;
  this.height    = canvas.height;
  this.length    = [];
  this.food      = {};
  this.score     = 0;
  this.direction = 'right';
  this.conf      = {
    cw   : 10,
    size : 5,
    fps  : 1000
  };
  
  // Merge Conf
  if (typeof conf == 'object') {
    for (var key in conf) {
      if (conf.hasOwnProperty(key)) {
        this.conf[key] = conf[key];
      }
    }
  }
  
};

/**
 * Game Component Snake
 */
Component.Snake = function(canvas, conf) {
  
  // Game Stage
  this.stage = new Component.Stage(canvas, conf);
  
  // Init Snake
  this.initSnake = function() {
    
    // Itaration in Snake Conf Size
    for (var i = 0; i < this.stage.conf.size; i++) {
      
      // Add Snake Cells
      this.stage.length.push({x: i, y:0});
  }
 };
  
  // Call init Snake
  this.initSnake();
  
  // Init Food  
  this.initFood = function() {
  
    // Add food on stage
    this.stage.food = {
   x: Math.round(Math.random() * (this.stage.width - this.stage.conf.cw) / this.stage.conf.cw), 
   y: Math.round(Math.random() * (this.stage.height - this.stage.conf.cw) / this.stage.conf.cw), 
  };
 };
  
  // Init Food
  this.initFood();
  
  // Restart Stage
  this.restart = function() {
    this.stage.length            = [];
    this.stage.food              = {};
    this.stage.score             = 0;
    this.stage.direction         = 'right';
    this.stage.keyEvent.pressKey = null;
    this.initSnake();
    this.initFood();
  };
};

/**
 * Game Draw
 */
Game.Draw = function(context, snake) {
  
  // Draw Stage
  this.drawStage = function() {
    
    // Check Keypress And Set Stage direction
    var keyPress = snake.stage.keyEvent.getKey(); 
    if (typeof(keyPress) != 'undefined') {
      snake.stage.direction = keyPress;
    }
    
    // Draw White Stage
  context.fillStyle = "white";
  context.fillRect(0, 0, snake.stage.width, snake.stage.height);
  
    // Snake Position
    var nx = snake.stage.length[0].x;
  var ny = snake.stage.length[0].y;
  
    // Add position by stage direction
    switch (snake.stage.direction) {
      case 'right':
        nx++;
        break;
      case 'left':
        nx--;
        break;
      case 'up':
        ny--;
        break;
      case 'down':
        ny++;
        break;
    }
    
    // Check Collision
    if (this.collision(nx, ny) == true) {
      snake.restart();
      return;
    }
    
    // Logic of Snake food
    if (nx == snake.stage.food.x && ny == snake.stage.food.y) {
      var tail = {x: nx, y: ny};
      snake.stage.score++;
      snake.initFood();
    } else {
      var tail = snake.stage.length.pop();
      tail.x   = nx;
      tail.y   = ny; 
    }
    snake.stage.length.unshift(tail);
    
    // Draw Snake
    for (var i = 0; i < snake.stage.length.length; i++) {
      var cell = snake.stage.length[i];
      this.drawCell(cell.x, cell.y);
    }
    
    // Draw Food
    this.drawCell(snake.stage.food.x, snake.stage.food.y);
    
    // Draw Score
    context.fillText('Score: ' + snake.stage.score, 5, (snake.stage.height - 5));
  };
  
  // Draw Cell
  this.drawCell = function(x, y) {
    context.fillStyle = 'rgb(170, 170, 170)';
    context.beginPath();
    context.arc((x * snake.stage.conf.cw + 6), (y * snake.stage.conf.cw + 6), 4, 0, 2*Math.PI, false);    
    context.fill();
  };
  
  // Check Collision with walls
  this.collision = function(nx, ny) {  
    if (nx == -1 || nx == (snake.stage.width / snake.stage.conf.cw) || ny == -1 || ny == (snake.stage.height / snake.stage.conf.cw)) {
      return true;
    }
    return false;    
 }
};


/**
 * Game Snake
 */
Game.Snake = function(elementId, conf) {
  
  // Sets
  var canvas   = document.getElementById(elementId);
  var context  = canvas.getContext("2d");
  var snake    = new Component.Snake(canvas, conf);
  var gameDraw = new Game.Draw(context, snake);
  
  // Game Interval
  setInterval(function() {gameDraw.drawStage();}, snake.stage.conf.fps);
};


/**
 * Window Load
 */
window.onload = function() {
  var snake = new Game.Snake('stage', {fps: 100, size: 4});
};

so you have to read the code and try it and hopefully works for you, it amazing chance to practice your skills that you learned, goodbye.

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