86 lines
2.9 KiB
Java
86 lines
2.9 KiB
Java
/*
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* opsu! - an open-source osu! client
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* Copyright (C) 2014, 2015 Jeffrey Han
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*
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* opsu! is free software: you can redistribute it and/or modify
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* it under the terms of the GNU 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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* opsu! 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with opsu!. If not, see <http://www.gnu.org/licenses/>.
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*/
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package itdelatrisu.opsu.objects.curves;
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import org.newdawn.slick.SlickException;
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/**
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* Representation of a Centripetal Catmull–Rom spline.
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* (Currently not technically Centripetal Catmull–Rom.)
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* http://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline
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*
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* @author fluddokt (https://github.com/fluddokt)
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*/
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public class CentripetalCatmullRom extends CurveType {
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/** The time values of the Catmull curve. */
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private float [] time;
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/** The control points of the Catmull curve. */
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private Vec2f[] points;
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/**
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* Constructor.
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* @param points the control points of the curve
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* @throws SlickException
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*/
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protected CentripetalCatmullRom(Vec2f[] points) throws SlickException {
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if (points.length != 4)
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throw new SlickException(String.format("Need exactly 4 points to initialize CentripetalCatmullRom, %d provided.", points.length));
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this.points = points;
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time = new float[4];
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time[0] = 0;
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float approxLength = 0;
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for (int i = 1; i < 4; i++) {
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float len = 0;
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if (i > 0)
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len = points[i].cpy().sub(points[i - 1]).len();
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if (len <= 0)
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len += 0.0001f;
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approxLength += len;
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// time[i] = (float) Math.sqrt(len) + time[i-1];// ^(0.5)
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time[i] = i;
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}
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init(approxLength / 2);
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}
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@Override
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public Vec2f pointAt(float t) {
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t = t * (time[2] - time[1]) + time[1];
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Vec2f A1 = points[0].cpy().scale((time[1] - t) / (time[1] - time[0]))
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.add(points[1].cpy().scale((t - time[0]) / (time[1] - time[0])));
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Vec2f A2 = points[1].cpy().scale((time[2] - t) / (time[2] - time[1]))
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.add(points[2].cpy().scale((t - time[1]) / (time[2] - time[1])));
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Vec2f A3 = points[2].cpy().scale((time[3] - t) / (time[3] - time[2]))
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.add(points[3].cpy().scale((t - time[2]) / (time[3] - time[2])));
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Vec2f B1 = A1.cpy().scale((time[2] - t) / (time[2] - time[0]))
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.add(A2.cpy().scale((t - time[0]) / (time[2] - time[0])));
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Vec2f B2 = A2.cpy().scale((time[3] - t) / (time[3] - time[1]))
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.add(A3.cpy().scale((t - time[1]) / (time[3] - time[1])));
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Vec2f C = B1.cpy().scale((time[2] - t) / (time[2] - time[1]))
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.add(B2.cpy().scale((t - time[1]) / (time[2] - time[1])));
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return C;
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}
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}
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