/*
 * Copyright (c) 2011-2019, The DART development contributors
 * All rights reserved.
 *
 * The list of contributors can be found at:
 *   https://github.com/dartsim/dart/blob/master/LICENSE
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 *   without modification, are permitted provided that the following
 *   conditions are met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
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 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
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 */

#ifndef DART_COLLISION_CONTACT_HPP_
#define DART_COLLISION_CONTACT_HPP_

#include <Eigen/Dense>
#include "dart/collision/SmartPointer.hpp"
#include "dart/dynamics/SmartPointer.hpp"

namespace dart {
namespace collision {

/// Contact information
struct Contact
{
  /// Default constructor
  Contact();

  /// Contact point w.r.t. the world frame
  Eigen::Vector3d point;

  /// Contact normal vector from bodyNode2 to bodyNode1 w.r.t. the world frame
  Eigen::Vector3d normal;

  /// Contact force acting on bodyNode1 w.r.t. the world frame
  ///
  /// The contact force acting on bodyNode2 is -force, which is the opposite
  /// direction of the force.
  Eigen::Vector3d force;

  /// First colliding collision object
  CollisionObject* collisionObject1;

  /// Second colliding collision object
  CollisionObject* collisionObject2;

  /// Penetration depth
  double penetrationDepth;

  // TODO(JS): triID1 will be deprecated when we don't use fcl_mesh
  /// \brief
  int triID1;

  // TODO(JS): triID2 will be deprecated when we don't use fcl_mesh
  /// \brief
  int triID2;

  // TODO(JS): userData is an experimental variable.
  /// \brief User data.
  void* userData;

  /// Returns the epsilon to be used for determination of zero-length normal.
  constexpr static double getNormalEpsilon();

  /// Returns the squired epsilon to be used for determination of zero-length
  /// normal.
  constexpr static double getNormalEpsilonSquared();

  /// Returns true if the length of a normal is less than the epsilon.
  static bool isZeroNormal(const Eigen::Vector3d& normal);

  /// Returns !isZeroNormal().
  static bool isNonZeroNormal(const Eigen::Vector3d& normal);
};

} // namespace collision
} // namespace dart

#include "dart/collision/detail/Contact-impl.hpp"

#endif // DART_COLLISION_CONTACT_HPP_
