Par Winzell
45abd9a903
git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@327 ed5b42cb-e716-0410-a449-f6a68f950b19
69 lines
2.3 KiB
ActionScript
69 lines
2.3 KiB
ActionScript
//
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// $Id$
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//
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// Nenya library - tools for developing networked games
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// Copyright (C) 2002-2007 Three Rings Design, Inc., All Rights Reserved
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// http://www.threerings.net/code/nenya/
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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.flash.path {
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/**
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* Interpolates cubically between two values, with beginning and end derivates set
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* to zero. See http://en.wikipedia.org/wiki/Cubic_Hermite_spline for details.
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*/
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public class HermiteFunc extends InterpFunc
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{
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public function HermiteFunc (start :int, end :int, startSlope :Number = 0, endSlope :Number = 0)
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{
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_p0 = start;
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_p1 = end;
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_m0 = startSlope;
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_m1 = endSlope;
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}
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// from InterpFunc
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override public function getValue (t :Number) :int
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{
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if (t >= 1) {
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return _p1;
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} else if (t < 0) { // cope with a funny startOffset
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return _p0;
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} else {
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var tt :Number = t*t;
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var ttt :Number = t2 * t;
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return int(_p0 * (2*ttt - 3*tt + 1) +
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_m0 * (ttt - 2*tt + t) +
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_p1 * (-2*ttt + 3*tt) +
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_m1 * (ttt - tt));
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}
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}
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/** The coefficient for the spline that interpolates the beginning point value. */
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protected var _p0 :Number;
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/** The coefficient for the spline that interpolates the end point value. */
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protected var _p1 :Number;
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/** The coefficient for the spline that interpolates the beginning point derivate. */
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protected var _m0 :Number;
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/** The coefficient for the spline that interpolates the end point derivate. */
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protected var _m1 :Number;
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}
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}
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