Michael Bayne
7428f885cf
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3628 542714f4-19e9-0310-aa3c-eee0fc999fb1
71 lines
2.2 KiB
Java
71 lines
2.2 KiB
Java
//
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// $Id$
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//
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// Narya library - tools for developing networked games
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// Copyright (C) 2002-2004 Three Rings Design, Inc., All Rights Reserved
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// http://www.threerings.net/code/narya/
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library 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 GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.threerings.media.tile;
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/**
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* Miscellaneous utility routines for working with tiles.
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*/
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public class TileUtil
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{
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/**
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* Generates a fully-qualified tile id given the supplied tileset id
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* and tile index.
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*/
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public static int getFQTileId (int tileSetId, int tileIndex)
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{
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return (tileSetId << 16) | tileIndex;
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}
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/**
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* Extracts the tile set id from the supplied fully qualified tile id.
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*/
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public static int getTileSetId (int fqTileId)
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{
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return (fqTileId >> 16);
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}
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/**
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* Extracts the tile index from the supplied fully qualified tile id.
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*/
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public static int getTileIndex (int fqTileId)
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{
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return (fqTileId & 0xFFFF);
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}
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/**
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* Compute some hash value for "randomizing" tileset picks
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* based on x and y coordinates.
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*
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* @return a positive, seemingly random number based on x and y.
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*/
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public static int getTileHash (int x, int y)
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{
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long seed = ((x ^ y) ^ MULTIPLIER) & MASK;
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long hash = (seed * MULTIPLIER + ADDEND) & MASK;
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return (int) (hash >>> 30);
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}
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protected static final long MULTIPLIER = 0x5DEECE66DL;
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protected static final long ADDEND = 0xBL;
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protected static final long MASK = (1L << 48) - 1;
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}
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