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#ifndef DART_COLLISION_FCL_FCLCOLLISIONDETECTOR_HPP_
#define DART_COLLISION_FCL_FCLCOLLISIONDETECTOR_HPP_

#include <vector>
#include "dart/collision/CollisionDetector.hpp"
#include "dart/collision/fcl/FCLTypes.hpp"

namespace dart {
namespace collision {

class FCLCollisionObject;

class FCLCollisionDetector : public CollisionDetector
{
public:
  using CollisionDetector::createCollisionGroup;

  static std::shared_ptr<FCLCollisionDetector> create();

  /// Whether to use analytic collision checking for primitive shapes.
  ///
  /// PRIMITIVE: Use FCL's analytic collision checking for primitive shapes.
  /// MESH: Don't use it. Instead, use approximate mesh shapes for the primitive
  /// shapes. The contact result is probably less accurate than the analytic
  /// result.
  ///
  /// Warning: FCL's primitive shape support is not complete. FCL 0.4.0 improved
  /// the support alot, but it still returns single contact point for a shape
  /// pair except for box-box collision. For this reason, we recommend using
  /// MESH until FCL fully supports primitive shapes.
  enum PrimitiveShape
  {
    PRIMITIVE = 0,
    MESH
  };

  /// Whether to use FCL's contact point computation.
  ///
  /// FCL: Use FCL's contact point computation.
  /// DART: Use DART's own contact point computation
  ///
  /// Warning: FCL's contact computation is not correct. See:
  /// https://github.com/flexible-collision-library/fcl/issues/106
  /// We recommend using DART until it's fixed in FCL.
  enum ContactPointComputationMethod
  {
    FCL = 0,
    DART
  };

  /// Constructor
  virtual ~FCLCollisionDetector();

  // Documentation inherited
  std::shared_ptr<CollisionDetector> cloneWithoutCollisionObjects()
      const override;

  // Documentation inherited
  const std::string& getType() const override;

  /// Get collision detector type for this class
  static const std::string& getStaticType();

  // Documentation inherited
  std::unique_ptr<CollisionGroup> createCollisionGroup() override;

  // Documentation inherited
  bool collide(
      CollisionGroup* group,
      const CollisionOption& option = CollisionOption(false, 1u, nullptr),
      CollisionResult* result = nullptr) override;

  // Documentation inherited
  bool collide(
      CollisionGroup* group1,
      CollisionGroup* group2,
      const CollisionOption& option = CollisionOption(false, 1u, nullptr),
      CollisionResult* result = nullptr) override;

  // Documentation inherited
  double distance(
      CollisionGroup* group,
      const DistanceOption& option = DistanceOption(false, 0.0, nullptr),
      DistanceResult* result = nullptr) override;

  // Documentation inherited
  double distance(
      CollisionGroup* group1,
      CollisionGroup* group2,
      const DistanceOption& option = DistanceOption(false, 0.0, nullptr),
      DistanceResult* result = nullptr) override;

  /// Set primitive shape type
  void setPrimitiveShapeType(PrimitiveShape type);

  /// Get primitive shape type
  PrimitiveShape getPrimitiveShapeType() const;

  /// Set contact point computation method
  void setContactPointComputationMethod(ContactPointComputationMethod method);

  /// Get contact point computation method
  ContactPointComputationMethod getContactPointComputationMethod() const;

protected:
  /// Constructor
  FCLCollisionDetector();

  // Documentation inherited
  std::unique_ptr<CollisionObject> createCollisionObject(
      const dynamics::ShapeFrame* shapeFrame) override;

  void refreshCollisionObject(CollisionObject* object) override;

  /// Return fcl::CollisionGeometry associated with give Shape. New
  /// fcl::CollisionGeome will be created if it hasn't created yet.
  fcl_shared_ptr<dart::collision::fcl::CollisionGeometry>
  claimFCLCollisionGeometry(const dynamics::ConstShapePtr& shape);

protected:
  PrimitiveShape mPrimitiveShapeType;

  ContactPointComputationMethod mContactPointComputationMethod;

private:
  /// This deleter is responsible for deleting fcl::CollisionGeometry and
  /// removing it from mShapeMap when it is not shared by any CollisionObjects.
  class FCLCollisionGeometryDeleter final
  {
  public:
    FCLCollisionGeometryDeleter(
        FCLCollisionDetector* cd, const dynamics::ConstShapePtr& shape);

    void operator()(dart::collision::fcl::CollisionGeometry* geom) const;

  private:
    FCLCollisionDetector* mFCLCollisionDetector;

    dynamics::ConstShapePtr mShape;
  };

  /// Information for a shape that was generated by this collision detector
  struct ShapeInfo final
  {
    /// A weak reference to the shape
    fcl_weak_ptr<dart::collision::fcl::CollisionGeometry> mShape;

    /// The last version of the shape, as known by this collision detector
    std::size_t mLastKnownVersion;
  };

  /// Create fcl::CollisionGeometry with the custom deleter
  /// FCLCollisionGeometryDeleter
  fcl_shared_ptr<dart::collision::fcl::CollisionGeometry>
  createFCLCollisionGeometry(
      const dynamics::ConstShapePtr& shape,
      FCLCollisionDetector::PrimitiveShape type,
      const FCLCollisionGeometryDeleter& deleter);

private:
  using ShapeMap = std::map<dynamics::ConstShapePtr, ShapeInfo>;

  ShapeMap mShapeMap;

  static Registrar<FCLCollisionDetector> mRegistrar;
};

} // namespace collision
} // namespace dart

#endif // DART_COLLISION_FCL_FCLCOLLISIONDETECTOR_HPP_
