/*
 *   GRacer
 *
 *   Copyright (C) 1999 Takashi Matsuda <matsu@users.sourceforge.net>
 *
 * 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 __GRACER_PHYSICS_H__
#define __GRACER_PHYSICS_H__

#include "gr_global.h"
#include "gr_matrix.h"
#include "gr_quat.h"

#define GRAVITY			9.8

typedef struct GrInertial
{
  double current;
  double target;
  double speed;
  double accel;

} GrInertial;

typedef struct GrRigidBody
{
  float mass;
  GrMatrix m_j;

  struct {
    GrVertexd pos, spd;
    GrVertexd rot, omg;
    GrQuaternion quat;
    GrVertex force;
    GrVertex m;
    GrMatrix m_zyx;	/* local coordinate to global */
    GrMatrix m_rzyx;	/* global coordinate to local */
  } state[2];

} GrRigidBody;


#ifdef __cplusplus
extern "C" {
#endif
#if 0
}
#endif


void gr_phisics_inertial_move		(GrInertial *value,
					 double h);
void gr_rigid_body_integral		(GrRigidBody *rb,
    					 int from,
					 double h);
void gr_rigid_body_reset		(GrRigidBody *rb, int which);
void gr_rigid_body_add_force_relative	(GrRigidBody *rb,
    					 int which,
    					 GrVertex *point,
					 GrVertex *force);
void gr_rigid_body_add_force		(GrRigidBody *rb,
    					 int which,
    					 GrVertex *point,
					 GrVertex *force);


#ifdef __cplusplus
}
#endif

#endif /* __GRACER_PHYSICS_H__ */