MT_ExpMap.h

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 2
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Original author: Laurence
 * Contributor(s): Brecht
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#ifndef MT_ExpMap_H
#define MT_ExpMap_H

#include <MT_assert.h>

#include "MT_Vector3.h"
#include "MT_Quaternion.h"
#include "MT_Matrix4x4.h"

const MT_Scalar MT_EXPMAP_MINANGLE (1e-7);

class MT_ExpMap {
public:

    MT_ExpMap() {}
    MT_ExpMap(const MT_Vector3& v) : m_v(v) { angleUpdated(); }

    MT_ExpMap(const float v[3]) : m_v(v) { angleUpdated(); }
    MT_ExpMap(const double v[3]) : m_v(v) { angleUpdated(); }

    MT_ExpMap(MT_Scalar x, MT_Scalar y, MT_Scalar z) :
        m_v(x, y, z) { angleUpdated(); }

    MT_ExpMap(
        const MT_Quaternion &q
    ) {
        setRotation(q);
    };

    const 
        MT_Vector3 &
    vector(
    ) const {
        return m_v;
    };

        void
    setRotation(
        const MT_Quaternion &q
    );

        const MT_Quaternion&
    getRotation(
    ) const;

        MT_Matrix3x3
    getMatrix(
    ) const; 
    
        void
    update(
        const MT_Vector3& dv
    );

        void
    partialDerivatives(
        MT_Matrix3x3& dRdx,
        MT_Matrix3x3& dRdy,
        MT_Matrix3x3& dRdz
    ) const ;
    
private :

    // m_v contains the exponential map, the other variables are
    // cached for efficiency
    
    MT_Vector3 m_v;
    MT_Scalar m_theta, m_sinp;
    MT_Quaternion m_q;

    // private methods

    // Compute partial derivatives dR (3x3 rotation matrix) / dVi (EM vector)
    // given the partial derivative dQ (Quaternion) / dVi (ith element of EM vector)

        void
    compute_dRdVi(
        const MT_Quaternion &dQdV,
        MT_Matrix3x3 & dRdVi
    ) const;

    // compute partial derivatives dQ/dVi

        void
    compute_dQdVi(
        MT_Quaternion *dQdX
    ) const ; 

    // reparametrize away from singularity

        void
    reParametrize(
    );

    // (re-)compute cached variables

        void
    angleUpdated(
    );
};

#endif