/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file physxWheelShape.h
 * @author enn0x
 * @date 2009-11-09
 */

#ifndef PHYSXWHEELSHAPE_H
#define PHYSXWHEELSHAPE_H

#include "pandabase.h"

#include "physxShape.h"
#include "physx_includes.h"

class PhysxWheelShapeDesc;
class PhysxSpringDesc;

/**
 * A special shape used for simulating a car wheel.  The -Y axis should be
 * directed toward the ground.
 *
 * A ray is cast from the shape's origin along the -Y axis.  When the ray
 * strikes something, and the distance is:
 *
 * - less than wheelRadius from the shape origin: a hard contact is created -
 * between wheelRadius and (suspensionTravel + wheelRadius): a soft suspension
 * contact is created - greater than (suspensionTravel + wheelRadius): no
 * contact is created.
 *
 * Thus at the point of greatest possible suspension compression the wheel
 * axle will pass through at the shape's origin.  At the point greatest
 * suspension extension the wheel axle will be a distance of suspensionTravel
 * from the shape's origin.
 *
 * The suspension's targetValue is 0 for real cars, which means that the
 * suspension tries to extend all the way.  Otherwise one can specify values
 * [0,1] for suspensions which have a spring to pull the wheel up when it is
 * extended too far.  0.5 will then fall halfway along suspensionTravel.
 *
 * The +Z axis is the 'forward' direction of travel for the wheel.  -Z is
 * backwards.  The wheel rolls forward when rotating around the positive
 * direction around the X axis.
 *
 * A positive wheel steering angle corresponds to a positive rotation around
 * the shape's Y axis.  (Castor angles are not modeled.)
 *
 * The coordinate frame of the shape is rigidly fixed on the car.
 */
class EXPCL_PANDAPHYSX PhysxWheelShape : public PhysxShape {
PUBLISHED:
  INLINE PhysxWheelShape();
  INLINE ~PhysxWheelShape();

  void save_to_desc(PhysxWheelShapeDesc &shapeDesc) const;

  void set_radius(float radius);
  void set_suspension_travel(float travel);
  void set_inverse_wheel_mass(float invMass);
  void set_motor_torque(float torque);
  void set_brake_torque(float torque);
  void set_steer_angle(float angle);
  void set_steer_angle_rad(float angle);
  void set_axle_speed(float speed);
  void set_wheel_flag(PhysxWheelShapeFlag flag, bool value);
  void set_suspension(const PhysxSpringDesc &spring);

  float get_radius() const;
  float get_suspension_travel() const;
  float get_inverse_wheel_mass() const;
  float get_motor_torque() const;
  float get_brake_torque() const;
  float get_steer_angle() const;
  float get_steer_angle_rad() const;
  float get_axle_speed() const;
  bool get_wheel_flag(PhysxWheelShapeFlag flag) const;

public:
  INLINE NxShape *ptr() const { return (NxShape *)_ptr; };

  void link(NxShape *shapePtr);
  void unlink();

private:
  NxWheelShape *_ptr;

public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    PhysxShape::init_type();
    register_type(_type_handle, "PhysxWheelShape",
                  PhysxShape::get_class_type());
  }
  virtual TypeHandle get_type() const {
    return get_class_type();
  }
  virtual TypeHandle force_init_type() {
    init_type();
    return get_class_type();
  }

private:
  static TypeHandle _type_handle;
};

#include "physxWheelShape.I"

#endif // PHYSXWHEELSHAPE_H