146 lines
4.1 KiB
JavaScript
146 lines
4.1 KiB
JavaScript
/**
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* Represents a classic map (level)
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*
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* Copyright (C) 2012 Mike Gerwitz
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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* Each map is concatenated in the file and consists of the following
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* information:
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*
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* - Playfield data (game objects), 16x16 multidimensional char array
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* - Level name, 31 characters
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* - Hint, 256 characters
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* - Author, 31 characters
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* - Difficulty, 16-bit integer, little endian
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*
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* One can easily calculate the position of the level in a file, given its
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* number, by multiplying by the size of the data structure (see TLEVEL, LTANK.H
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* in the original sources).
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*
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* It is worth mentioning how the playfield data is stored. Since the
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* multidimensional array is defined as [x][y], the array is created as an
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* "array of columns", meaning that the data is organized in columns instead of
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* rows. For example, when viewing the data in a HEX editor that displays 16
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* bytes per line (e.g. xxd), the map would appear to be mirrored rotated 90
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* degrees counter-clockwise. To make it easier to visualize, one can create a
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* map with a number of tunnels in a pattern to take advantage of the ASCII
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* display.
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*/
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/**
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* Represents a classic map, as they exist in the original game.
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*
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* Classic maps are 16x16 tiles in size (for a total of 256 tiles).
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*/
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ltjs.ClassicMap = Class( 'ClassicMap' )
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.implement( ltjs.Map )
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.extend(
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{
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'private const _SIZE': 590,
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/**
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* Game object size
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*
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* The game objects are stores as a 16x16 multi-dimensional signed char
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* array (in the C sources).
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*
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* @type {number}
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*/
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'private const _GOSIZE': 256,
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/**
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* Map set data (binary string)
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* @type {string}
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*/
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'private _data': null,
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/**
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* Map id (1-indexed)
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* @type {string}
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*/
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'private _id': 0,
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/**
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* Initialize map with map data and the given id
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*
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* @param {ltjs.MapSet} set map set data
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* @param {number} id 1-indexed map id
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*/
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__construct: function( data, id )
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{
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this._data = ''+( data );
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this._id = +id;
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},
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/**
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* Retrieve game objects
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*
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* The game objects are returned in a manner consistent with the original
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* sources - in columns, not rows. The reason for this is that the original
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* game uses a multi-dimensional array [x][y], which creates an array of
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* columns (TPLAYFIELD, LTANK.H).
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*
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* @return {Array.<number>} array of game objects
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*/
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'public getObjects': function()
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{
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// calculate offset in LVL file
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var offset = ( this.__self.$( '_SIZE' ) * ( this._id - 1 ) );
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return this._getMapData( offset );
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},
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/**
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* Retrieve the map data (game objects only) at the requested offset
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*
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* The object data at the requested position will be loaded and converted to
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* integers (from a binary string).
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*
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* @param {number} offset offset of the requested map data
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*
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* @return {Array.<number>} converted map data
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*/
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'private _getMapData': function( offset )
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{
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var tiles = this._data.substr( offset, this.__self.$( '_GOSIZE' ) )
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.split( '' ),
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i = tiles.length;
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while ( i-- )
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{
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tiles[ i ] = tiles[ i ].charCodeAt( 0 );
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}
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return tiles;
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},
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/**
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* Retrieve map dimensions
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*
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* @return {Array.<number>} width and height in tiles
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*/
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'public getDimensions': function()
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{
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return [ 16, 16 ];
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}
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} );
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