Source: Item.js

/*jslint plusplus: true, white: true, indent: 2, maxlen: 90 */
/*global $wk$, $app$*/
/**
 *  @author    Wolfgang Kowarschick
 *  @copyright 2013, Wolfgang Kowarschick
 *  <br/>
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted under the terms of the 
 *  Creative Commons License Attribution-NonCommercial-ShareAlike 3.0 Unported    
 *  (CC BY-NC-SA 3.0: http://creativecommons.org/licenses/by-nc-sa/3.0/). 
 */

$wk$(this.document,
function(document)
{ "use strict";
////////////////////////////////////////////////////////////////////////////////
// Class "Item"
////////////////////////////////////////////////////////////////////////////////

//------------------------------------------------------------------------------
// Constructor
//------------------------------------------------------------------------------
/** 
 *  @class
 *  @name $app$.game.snake.Item
 *  
 *  @param {int} p_x The x position of the item.
 *  @param {int} p_y The y position of the item.
 */
$wk$.WKcClass(
{ name: "$app$.game.snake.Item",
        
  methods:
  { init:
    function(p_x, p_y)
    { this.x = p_x;
      this.y = p_y;
    }

    /** 
     *  The pixel size of an item. This value is equal for all items!
     *  @var {String} $app$.game.snake.Item#size
     */
    /** 
     *  The x-position of the item.
     *  @var {Number} $app$.game.snake.Item#x  
     */
    /** 
     *  The y-position of the item.
     *  @var {Number} $app$.game.snake.Item#y  
     */
    /** 
     *  The image (a mini canvas) of the item.
     *  @var {String} $app$.game.snake.Item#image 
     */
  },

  staticMethods:
  { /**
     *  Initializes the class <code>Item</code> and all its subclasses.
     *  
     *  @method
     *  @name $app$.game.snake.Item.init
     *  
     *  @param {Object} p_init 
     *         Should contain the attributes
     *           <code>size</code> 
     *             (the size of every item; size == width == height) and
     *           <code>subclasses</code> 
     *             (an object; for every subclasses of 
     *              <code>Item</code> there should be one attribute;
     *              the name of the attribute must be equal to
     *              the name of the subclass and the value
     *              should contain proper initialization values for
     *              the subclass).
     */
    initialize:
    function(p_init)
    { var l_size       = p_init.size,
          l_size2,
          l_anchor,
          l_subclasses = p_init.subclasses,
          l_subclass   = null,
          l_init,
          l_canvas,
          l_context;

      // All items have the same size. So it is stored as prototype value.
      this.prototype.size = l_size;
  
      // Create the image for each item type. 
      /*jslint forin: true*/
      for(l_subclass in l_subclasses)
      { l_init = l_subclasses[l_subclass];
  
        l_canvas = document.createElement("canvas");
        l_canvas.width  = l_size;
        l_canvas.height = l_size;
        l_context = l_canvas.getContext("2d");

        l_context.beginPath();
    
        if (l_init.type === "circle")
        { l_anchor = l_size/2;
          l_context.arc(l_anchor, l_anchor, l_init.radius, 0, 2*Math.PI, true); 
        }
        else if (l_init.type === "square")
        { l_size2  = l_init.size;
          l_anchor = (l_size-l_size2)/2;
          l_context.rect(l_anchor, l_anchor, l_size2, l_size2);
        }

        l_context.fillStyle   = l_init.color; 
        l_context.lineWidth   = l_init.borderSize;
        l_context.strokeStyle = l_init.borderColor;
    
        l_context.stroke();
        l_context.fill();
    
        // All items of a subclass of Item share the same image.
        // So that image is stored as prototype value of the particular class.
        $app$.game.snake[l_subclass].prototype.image = l_canvas;
      }
    }
  }
});

////////////////////////////////////////////////////////////////////////////////
// Class "Body"
////////////////////////////////////////////////////////////////////////////////

/** 
 *  @class
 *  @name    $app$.game.snake.Body
 *  @extends $app$.game.snake.Item
 *  
 *  @param {int} p_x The x position of the item.
 *  @param {int} p_y The y position of the item.
 */
$wk$.WKcClass(
{ name:    "$app$.game.snake.Body",
  isa:     "$app$.game.snake.Item",
  methods: { init: function(p_x, p_y) { this.$super$(p_x, p_y); } 

   /** 
    *  The predecessor of the body item. Each body item of the snake 
    *  with exception of the head has another body item as predecessor.
    *  @var {Number} $app$.game.snake.Body#pred  
    */
  }
});

////////////////////////////////////////////////////////////////////////////////
// Class "Wall"
////////////////////////////////////////////////////////////////////////////////

/** 
 *  @class
 *  @name    $app$.game.snake.Wall
 *  @extends $app$.game.snake.Item
 *  
 *  @param {int} p_x The x position of the item.
 *  @param {int} p_y The y position of the item.
 */
$wk$.WKcClass(
{ name:    "$app$.game.snake.Wall",
  isa:     "$app$.game.snake.Item",
  methods: { init: function(p_x, p_y) { this.$super$(p_x, p_y); } }
});

////////////////////////////////////////////////////////////////////////////////
// Class "Food"
////////////////////////////////////////////////////////////////////////////////

/** 
 *  @class
 *  @name    $app$.game.snake.Food
 *  @extends $app$.game.snake.Item
 *  
 *  @param {int} p_x The x position of the item.
 *  @param {int} p_y The y position of the item.
 */
$wk$.WKcClass(
{ name:    "$app$.game.snake.Food",
  isa:     "$app$.game.snake.Item",
  methods: { init: function(p_x, p_y) { this.$super$(p_x, p_y); } }
});

////////////////////////////////////////////////////////////////////////////////
// End of Classes
////////////////////////////////////////////////////////////////////////////////
});