rctracker.h

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/*
    Sheep - A Rigid Body Dynamics Engine
    Copyright (C) 2001-2004 Francois Beaune
    Contact: http://toxicengine.sourceforge.net/

    This file is part of Sheep.

    Sheep 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.

    Sheep 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 Sheep; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef SHEEP_DYNAMICS_RCTRACKER_H
#define SHEEP_DYNAMICS_RCTRACKER_H

#include "common/math/matrix.h"
#include "common/math/real.h"
#include "common/math/vector.h"
#include "common/math/vector3.h"
#include "contact.h"

#include <algorithm>    // std::find(), std::remove_if()
#include <cassert>
#include <list>
#include <vector>

namespace sheep {

    class RCTracker {
    public:
        inline void Reset();

        inline void Insert(Contact &c);

        void ResolveAll();

        inline ContactVector &GetRestingContacts();

    private:
        // Resting contacts to keep track of. A vector is convenient to store
        // a set of resting contacts since they need to be accessed randomly.
        ContactVector m_resting_contacts;

        Matrix compute_A_matrix();
        Vector compute_b_vector();

        class index_set : public std::list<int> {
        public:
            bool Contains(int i) const {
                return std::find(begin(), end(), i) != end();
            }
        };

        index_set C, NC;

        Vector fdirection(const Matrix &A, int d);

        void maxstep(const Vector &a,
            const Vector &f,
            const Vector &delta_a,
            const Vector &delta_f,
            int d, Real *s, int *j);

        void drive_to_zero(const Matrix &A, Vector &f, Vector &a, int d);

        Vector compute_forces(const Matrix &A, const Vector &b);

        struct is_inactivated_rc {
            bool operator()(Contact &c) const;
        };

        void remove_inactivated_rc();
    };

#include "rctracker.inl"

}

#endif  // !SHEEP_DYNAMICS_RCTRACKER_H

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