Source: Plane.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 "Plane"
////////////////////////////////////////////////////////////////////////////////

// import
var Item = $app$.game.snake.Item,
    Wall = $app$.game.snake.Wall,
    Food = $app$.game.snake.Food;

/** 
 *  @class
 *  @name $app$.game.snake.Plane
 *  
 *  @param {Object} p_init Should contain the attributes
 *                         <code>canvasID</code> 
 *                           (the id of the canvas tag),
 *                         <code>colsNr</code> 
 *                           (the number of columns of the plane),
 *                         <code>rowsNr</code> 
 *                           (the number of rows of the plane),
 *                         <code>item</code>
 *                           (the initialization object for the items
 *                           that are placed on the plane).
 */
$wk$.WKcClass(
{ name: "$app$.game.snake.Plane",
 
  methods:
  { init:    
    function (p_init)
    { var l_init_item = p_init.item,
          l_item_size = l_init_item.size,
          l_canvas    = document.getElementById(p_init.canvasID);

      // Initialize the canvas.
      l_canvas.width  = p_init.colsNr*l_item_size;
      l_canvas.height = p_init.rowsNr*l_item_size;
      this.v_canvas   = l_canvas;
      this.v_context  = l_canvas.getContext("2d");
      this.v_cols_nr  = p_init.colsNr;
      this.v_rows_nr  = p_init.rowsNr;
  
      // Initialize the class "Item".
      Item.initialize(l_init_item);
  
      this.reset();
    },

  /**
   *  Resets the plane. 
   *  
   *  @method
   *  @name $app$.game.snake.Plane#reset
   */
  reset:
    function()
    { var i, j, m, n,
          l_plane   = [],
          l_canvas  = this.v_canvas,
          l_rows_nr = this.v_rows_nr,
          l_cols_nr = this.v_cols_nr;
    
      // No food has been placed on the canvas.
      this.foodNr = 0;
    
      // Clear the canvas
      this.v_context.clearRect(0, 0, l_canvas.width, l_canvas.height);

      // Initialize the plane. Draw the wall.
      this.v_plane     = l_plane;
      for (i=0, n=l_cols_nr, m=l_rows_nr-1; i<n; i++)
      { l_plane[i] = [];
        this.addItem(new Wall(i,0));
        this.addItem(new Wall(i,m));
      }
      for (j=1, m=l_rows_nr-1, n=l_cols_nr-1; j<m; j++)
      { this.addItem(new Wall(0,j));
        this.addItem(new Wall(n,j));
      }
    },

  /**
   *  Adds an item to the plane. 
   *  
   *  @method
   *  @name $app$.game.snake.Plane#addItem
   *  
   *  @param {$app$.game.snake.Item} p_item The item to be added.
   */ 
  addItem:
    function(p_item)
    { var l_image     = p_item.image,
          l_item_size = p_item.size,
          l_item_x    = p_item.x,
          l_item_y    = p_item.y,
          l_x         = l_item_x*l_item_size,
          l_y         = l_item_y*l_item_size;
      this.v_plane[l_item_x][l_item_y] = p_item; 
      this.v_context.clearRect(l_x, l_y, l_item_size, l_item_size);
      this.v_context.drawImage(l_image, l_x, l_y);
    },
  
  /**
   *  Removes an item from the plane. 
   *  
   *  @method
   *  @name $app$.game.snake.Plane#removeItem
   *  
   *  @param {$app$.game.snake.Item} p_item The item to be removed.
   */ 
  removeItem:
    function(p_item)
    { var l_item_size = p_item.size,
          l_item_x    = p_item.x,
          l_item_y    = p_item.y,
          l_x         = l_item_x*l_item_size,
          l_y         = l_item_y*l_item_size;
      delete this.v_plane[l_item_x][l_item_y]; 
      this.v_context.clearRect(l_x, l_y, l_item_size, l_item_size);
    },
  
  /**
   *  Returns the item currently being placed on a specific field of the plane.
   *  
   *  @method
   *  @name $app$.game.snake.Plane#getItem
   *  
   *  @param {int} p_x The x-position of the item to be fetched.
   *  @param {int} p_y The y-position of the item to be fetched.
   *  @returns {$app$.game.snake.Item} 
   *           The item at position (<code>p_x</code>,  <code>p_y</code>)
   *           of the field.
   */ 
  getItem:
    function(p_x, p_y)
    { return this.v_plane[p_x][p_y]; },
    
  /**
   *  Places food on some empty place of the plane.
   *
   *  @method
   *  @name $app$.game.snake.Plane#addFood
   */ 
  addFood:
    function()
    { var l_plane   = this.v_plane,
          l_cols_nr = this.v_cols_nr-1,
          l_rows_nr = this.v_rows_nr-1,
          l_x,
          l_y;
    
       // Find an empty filed on the plane.
       do 
       { l_x = 1 + Math.floor(Math.random()*l_cols_nr); 
         l_y = 1 + Math.floor(Math.random()*l_rows_nr); 
       }
       while (l_plane[l_x][l_y]);
       
       // Put food into that field.
       this.addItem(new Food(l_x, l_y));
       this.foodNr++;
    }  
  }
});

////////////////////////////////////////////////////////////////////////////////
// End of Class "Plane"
////////////////////////////////////////////////////////////////////////////////
});