/****************************************************************************

 Copyright (c) 2018  GeometryFactory Sarl (France).
 Copyright (C) 2002-2014 Gilles Debunne. All rights reserved.

 This file is part of a fork of the QGLViewer library version 2.7.0.

*****************************************************************************/
// $URL: https://github.com/CGAL/cgal/blob/v6.1/GraphicsView/include/CGAL/Qt/manipulatedCameraFrame.h $
// $Id: include/CGAL/Qt/manipulatedCameraFrame.h b26b07a1242 $
// SPDX-License-Identifier: GPL-3.0-only

#ifndef QGLVIEWER_MANIPULATED_CAMERA_FRAME_H
#define QGLVIEWER_MANIPULATED_CAMERA_FRAME_H
#include <QTimer>

#include <CGAL/export/Qt.h>
#include <CGAL/Qt/manipulatedFrame.h>
#include <CGAL/Qt/camera.h>

namespace CGAL{
namespace qglviewer {
/*! \brief The ManipulatedCameraFrame class represents a ManipulatedFrame with
  Camera specific mouse bindings. \class ManipulatedCameraFrame
  manipulatedCameraFrame.h CGAL::QGLViewer/manipulatedCameraFrame.h

  A ManipulatedCameraFrame is a specialization of a ManipulatedFrame, designed
  to be set as the Camera::frame(). Mouse motions are basically interpreted in a
  negated way: when the mouse goes to the right, the ManipulatedFrame
  translation goes to the right, while the ManipulatedCameraFrame has to go to
  the \e left, so that the \e scene seems to move to the right.

  A ManipulatedCameraFrame rotates around its pivotPoint(), which corresponds to
  the associated Camera::pivotPoint().

  A ManipulatedCameraFrame can also "fly" in the scene. It basically moves
  forward, and turns according to the mouse motion. See flySpeed(),
  sceneUpVector() and the MOVE_FORWARD and MOVE_BACKWARD
  MouseAction.

  See the <a href="../mouse.html">mouse page</a> for a description of the
  possible actions that can be performed using the mouse and their bindings.
  \nosubgrouping */
class CGAL_QT_EXPORT ManipulatedCameraFrame : public ManipulatedFrame {
#ifndef DOXYGEN
  friend class Camera;
  friend class ::CGAL::QGLViewer;
#endif

  Q_OBJECT

public:
  ManipulatedCameraFrame();
  /*! Virtual destructor. Empty. */
  virtual ~ManipulatedCameraFrame() {}

  ManipulatedCameraFrame(const ManipulatedCameraFrame &mcf);
  ManipulatedCameraFrame &operator=(const ManipulatedCameraFrame &mcf);

  /*! @name Pivot point */
  //@{
public:
  /*! Returns the point the ManipulatedCameraFrame pivot point, around which the
  camera rotates.

  It is defined in the world coordinate system. Default value is (0,0,0).

  When the ManipulatedCameraFrame is associated to a Camera,
  Camera::pivotPoint() also returns this value. This point can interactively be
  changed using the mouse (see Camera::setPivotPointFromPixel() and
  RAP_FROM_PIXEL and RAP_IS_CENTER in the <a
  href="../mouse.html">mouse page</a>). */
  Vec pivotPoint() const { return pivotPoint_; }
  /*! Sets the pivotPoint(), defined in the world coordinate system. */
  void setPivotPoint(const Vec &point) { pivotPoint_ = point; }

  //@}

  /*! @name Camera manipulation */
  //@{
public:
  /*! Returns \c true when the frame's rotation is constrained around the
     sceneUpVector(), and \c false otherwise, when the rotation is completely
     free (default).

          In free mode, the associated camera can be arbitrarily rotated in the
     scene, along its three axis, thus possibly leading to any arbitrary
     orientation.

          When you setRotatesAroundUpVector() to \c true, the sceneUpVector()
     defines a 'vertical' direction around which the camera rotates. The camera
     can rotate left or right, around this axis. It can also be moved up or down
     to show the 'top' and 'bottom' views of the scene. As a result, the
     sceneUpVector() will always appear vertical in the scene, and the horizon
     is preserved and stays projected along the camera's horizontal axis.

          Note that setting this value to \c true when the sceneUpVector() is
     not already vertically projected will break these invariants. It will also
     limit the possible movement of the camera, possibly up to a lock when the
     sceneUpVector() is projected horizontally. Use Camera::setUpVector() to
     define the sceneUpVector() and align the camera before calling this method
     to ensure this does not happen. */
  bool rotatesAroundUpVector() const { return rotatesAroundUpVector_; }
  /*! Sets the value of rotatesAroundUpVector().

     Default value is false (free rotation). */
  void setRotatesAroundUpVector(bool constrained) {
    rotatesAroundUpVector_ = constrained;
  }

  /*! Returns whether or not the ZOOM action zooms on the pivot
    point.

    When set to \c false (default), a zoom action will move the camera along its
    Camera::viewDirection(), i.e. back and forth along a direction perpendicular
    to the projection screen.

    setZoomsOnPivotPoint() to \c true will move the camera along an axis defined
    by the Camera::pivotPoint() and its current position instead. As a result,
    the projected position of the pivot point on screen will stay the same
    during a zoom. */
  bool zoomsOnPivotPoint() const { return zoomsOnPivotPoint_; }
  /*! Sets the value of zoomsOnPivotPoint().

     Default value is false. */
  void setZoomsOnPivotPoint(bool enabled) { zoomsOnPivotPoint_ = enabled; }

private:
#ifndef DOXYGEN
  void zoom(qreal delta, const Camera *const camera);
#endif
  //@}

  /*! @name Fly parameters */
  //@{
public Q_SLOTS:
  /*! Sets the flySpeed(), defined in OpenGL units.

  Default value is 0.0, but it is modified according to the
  CGAL::QGLViewer::sceneRadius() when the ManipulatedCameraFrame is set as the
  Camera::frame(). */
  void setFlySpeed(qreal speed) { flySpeed_ = speed; }

  /*! Sets the sceneUpVector(), defined in the world coordinate system.

  Default value is (0,1,0), but it is updated by the Camera when this object is
  set as its Camera::frame(). Using Camera::setUpVector() instead is probably a
  better solution. */
  void setSceneUpVector(const Vec &up) { sceneUpVector_ = up; }

public:
  /*! Returns the fly speed, expressed in OpenGL units.

  It corresponds to the incremental displacement that is periodically applied to
  the ManipulatedCameraFrame position when a MOVE_FORWARD or
  MOVE_BACKWARD MouseAction is proceeded.

  \attention When the ManipulatedCameraFrame is set as the Camera::frame(), this
  value is set according to the CGAL::QGLViewer::sceneRadius() by
  CGAL::QGLViewer::setSceneRadius(). */
  qreal flySpeed() const { return flySpeed_; }

  /*! Returns the up vector of the scene, expressed in the world coordinate
  system.

  In 'fly mode' (corresponding to the MOVE_FORWARD and
  MOVE_BACKWARD MouseAction bindings), horizontal
  displacements of the mouse rotate the ManipulatedCameraFrame around this
  vector. Vertical displacements rotate always around the Camera \c X axis.

  This value is also used when setRotationIsConstrained() is set to \c true to
  define the up vector (and incidentally the 'horizon' plane) around which the
  camera will rotate.

  Default value is (0,1,0), but it is updated by the Camera when this object is
  set as its Camera::frame(). Camera::setOrientation() and
  Camera::setUpVector()) directly modify this value and should be used instead.
*/
  Vec sceneUpVector() const { return sceneUpVector_; }

#ifndef DOXYGEN
  Vec flyUpVector() const;
  void setFlyUpVector(const Vec &up);
#endif
  //@}

  /*! @name Mouse event handlers */
  //@{
protected:
  virtual void mouseReleaseEvent(QMouseEvent *const event,
                                 Camera *const camera);
  virtual void mouseMoveEvent(QMouseEvent *const event, Camera *const camera);
  virtual void wheelEvent(QWheelEvent *const event, Camera *const camera);
  //@}

  /*! @name Spinning */
  //@{
protected Q_SLOTS:
  virtual void spin();
  //@}

#ifndef DOXYGEN
protected:
  virtual void startAction(
      int ma,
      bool withConstraint = true); // int is really a MouseAction
#endif

private Q_SLOTS:
  virtual void flyUpdate();

private:
  void updateSceneUpVector();
  Quaternion turnQuaternion(int x, const Camera *const camera);
  Quaternion pitchYawQuaternion(int x, int y, const Camera *const camera);

private:
  // Fly mode data
  qreal flySpeed_;
  qreal driveSpeed_;
  Vec sceneUpVector_;
  QTimer flyTimer_;

  bool rotatesAroundUpVector_;
  // Inverse the direction of an horizontal mouse motion. Depends on the
  // projected screen orientation of the vertical axis when the mouse button is
  // pressed.
  bool constrainedRotationIsReversed_;

  bool zoomsOnPivotPoint_;

  Vec pivotPoint_;
};

}} // namespace CGAL::qglviewer

#ifdef CGAL_HEADER_ONLY
//#include <CGAL/Qt/qglviewer_impl_list.h>
#endif // CGAL_HEADER_ONLY
#endif // QGLVIEWER_MANIPULATED_CAMERA_FRAME_H

