/* 
 * PROJECT: NyARToolkitCS(Extension)
 * --------------------------------------------------------------------------------
 * The NyARToolkitCS is Java edition ARToolKit class library.
 * Copyright (C)2008-2009 Ryo Iizuka
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * For further information please contact.
 *	http://nyatla.jp/nyatoolkit/
 *	<airmail(at)ebony.plala.or.jp> or <nyatla(at)nyatla.jp>
 * 
 */
using System;

namespace jp.nyatla.nyartoolkit.cs.core
{
    public class NyARQuaternion
    {
        public double x;
        public double y;
        public double z;
        public double w;

        public void setFromMatrix(NyARDoubleMatrix44 i_mat)
        {
            // 最大成分を検索
            double elem0 = i_mat.m00 - i_mat.m11 - i_mat.m22 + 1.0;
            double elem1 = -i_mat.m00 + i_mat.m11 - i_mat.m22 + 1.0;
            double elem2 = -i_mat.m00 - i_mat.m11 + i_mat.m22 + 1.0;
            double elem3 = i_mat.m00 + i_mat.m11 + i_mat.m22 + 1.0;
            if (elem0 > elem1 && elem0 > elem2 && elem0 > elem3)
            {
                double v = Math.Sqrt(elem0) * 0.5;
                double mult = 0.25 / v;
                this.x = v;
                this.y = ((i_mat.m10 + i_mat.m01) * mult);
                this.z = ((i_mat.m02 + i_mat.m20) * mult);
                this.w = ((i_mat.m21 - i_mat.m12) * mult);
            }
            else if (elem1 > elem2 && elem1 > elem3)
            {
                double v = Math.Sqrt(elem1) * 0.5;
                double mult = 0.25 / v;
                this.x = ((i_mat.m10 + i_mat.m01) * mult);
                this.y = (v);
                this.z = ((i_mat.m21 + i_mat.m12) * mult);
                this.w = ((i_mat.m02 - i_mat.m20) * mult);
            }
            else if (elem2 > elem3)
            {
                double v = Math.Sqrt(elem2) * 0.5;
                double mult = 0.25 / v;
                this.x = ((i_mat.m02 + i_mat.m20) * mult);
                this.y = ((i_mat.m21 + i_mat.m12) * mult);
                this.z = (v);
                this.w = ((i_mat.m10 - i_mat.m01) * mult);
            }
            else
            {
                double v = Math.Sqrt(elem3) * 0.5;
                double mult = 0.25 / v;
                this.x = ((i_mat.m21 - i_mat.m12) * mult);
                this.y = ((i_mat.m02 - i_mat.m20) * mult);
                this.z = ((i_mat.m10 - i_mat.m01) * mult);
                this.w = v;
            }
            return;
        }
    }
}