//  $Id: linear_mover.hxx,v 1.0 2002/10/13 16:39:59 grumbel Exp $
// 
//  Pingus - A free Lemmings clone
//  Copyright (C) 2000 Ingo Ruhnke <address@hidden>
//
//  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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

#ifndef HEADER_PINGUS_LINEAR_MOVER_HXX
#define HEADER_PINGUS_LINEAR_MOVER_HXX

#include "../mover.hxx"

namespace Movers {

template <class Collider>
class LinearMover : public Mover<Collider>
{
  public:
    /** Constructor */
    LinearMover(World* const world_arg, const Vector& pos_arg);

    /** Destructor */
    ~LinearMover();

    /** Updates the position of the object taking into account collisions */
    void update(const Vector& move, Collider collision_at);
};

template <class Collider>
LinearMover<Collider>::LinearMover(World* const world_arg,
				    const Vector& pos_arg)
  : Mover<Collider>(world_arg, pos_arg)
{
}

template <class Collider>
LinearMover<Collider>::~LinearMover()
{
}

template <class Collider>
void LinearMover<Collider>::update(const Vector& move, Collider collision_at)
{
  float move_length = move.length();
  Vector target_pos = pos + move;
  Vector step_vector = move;

  step_vector.normalize();

  collision = false;

  // Move to the destination one unit vector at a time
  for (float i = 0; i < move_length && !collision; ++i)
    {
      pos += step_vector;

      collision = collision_at(world, pos);
    }

  // If on a collision pixel, back away from it.
  if (collision)
    pos -= step_vector;

  remaining_move = target_pos - pos;
}

#endif

} // namespace Movers

/* EOF */