/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkProp3DAxisFollower.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/**
 * @class   vtkProp3DAxisFollower
 * @brief   a subclass of vtkProp3DFollower that ensures
 * that data is always parallel to the axis defined by a vtkAxisActor.
 *
 * vtkProp3DAxisFollower is a subclass of vtkProp3DFollower that always follows
 * its specified axis. More specifically it will not change its position or
 * scale, but it will continually update its orientation so that it is aligned
 * with the axis and facing at angle to the camera to provide maximum visibilty.
 * This is typically used for text labels for 3d plots.
 * @sa
 * vtkFollower vtkAxisFollower vtkProp3DFollower
*/

#ifndef vtkProp3DAxisFollower_h
#define vtkProp3DAxisFollower_h

#include "vtkRenderingAnnotationModule.h" // For export macro
#include "vtkProp3DFollower.h"
#include "vtkWeakPointer.h" // For vtkWeakPointer

class vtkAxisActor;
class vtkViewport;

class VTKRENDERINGANNOTATION_EXPORT vtkProp3DAxisFollower
  : public vtkProp3DFollower
{
 public:
  /**
   * Creates a follower with no camera set.
   */
  static vtkProp3DAxisFollower *New();

  //@{
  /**
   * Standard VTK methods for type and printing.
   */
  vtkTypeMacro(vtkProp3DAxisFollower,vtkProp3DFollower);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  //@}

 //@{
 /**
  * Set axis that needs to be followed.
  */
 virtual void SetAxis(vtkAxisActor*);
 virtual vtkAxisActor* GetAxis();
 //@}

 //@{
 /**
  * Set/Get state of auto center mode where additional
  * translation will be added to make sure the underlying
  * geometry has its pivot point at the center of its bounds.
  */
 vtkSetMacro(AutoCenter, int);
 vtkGetMacro(AutoCenter, int);
 vtkBooleanMacro(AutoCenter, int);
 //@}

 //@{
 /**
  * Enable / disable use of distance based LOD. If enabled the actor
  * will not be visible at a certain distance from the camera.
  * Default is false.
  */
 vtkSetMacro(EnableDistanceLOD, int);
 vtkGetMacro(EnableDistanceLOD, int);
 //@}

 //@{
 /**
  * Set distance LOD threshold (0.0 - 1.0).This determines at what fraction
  * of camera far clip range, actor is not visible.
  * Default is 0.80.
  */
 vtkSetClampMacro(DistanceLODThreshold, double, 0.0, 1.0);
 vtkGetMacro(DistanceLODThreshold, double);
 //@}

 //@{
 /**
  * Enable / disable use of view angle based LOD. If enabled the actor
  * will not be visible at a certain view angle.
  * Default is true.
  */
 vtkSetMacro(EnableViewAngleLOD, int);
 vtkGetMacro(EnableViewAngleLOD, int);
 //@}

 //@{
 /**
  * Set view angle LOD threshold (0.0 - 1.0).This determines at what view
  * angle to geometry will make the geometry not visible.
  * Default is 0.34.
  */
 vtkSetClampMacro(ViewAngleLODThreshold, double, 0.0, 1.0);
 vtkGetMacro(ViewAngleLODThreshold, double);
 //@}

 //@{
 /**
  * Set/Get the desired screen vertical offset from the axis.
  * Convenience method, using a zero horizontal offset
  */
 double GetScreenOffset();
 void SetScreenOffset(double offset);
 //@}

 //@{
 /**
  * Set/Get the desired screen offset from the axis.
  */
 vtkSetVector2Macro(ScreenOffsetVector, double);
 vtkGetVector2Macro(ScreenOffsetVector, double);
 //@}

  /**
   * Generate the matrix based on ivars. This method overloads its superclasses
   * ComputeMatrix() method due to the special vtkProp3DAxisFollower matrix operations.
   */
  void ComputeMatrix() override;

  /**
   * Shallow copy of a follower. Overloads the virtual vtkProp method.
   */
  void ShallowCopy(vtkProp *prop) override;

 /**
  * Calculate scale factor to maintain same size of a object
  * on the screen.
  */
 static double AutoScale(vtkViewport *viewport, vtkCamera * camera,
                         double screenSize, double position[3]);

  //@{
  /**
   * This causes the actor to be rendered. It in turn will render the actor's
   * property, texture map and then mapper. If a property hasn't been
   * assigned, then the actor will create one automatically.
   */
  int RenderOpaqueGeometry(vtkViewport *viewport) override;
  int RenderTranslucentPolygonalGeometry(vtkViewport *viewport) override;
  int RenderVolumetricGeometry(vtkViewport *viewport) override;
  //@}

  virtual void SetViewport(vtkViewport* viewport);
  virtual vtkViewport* GetViewport();

protected:
  vtkProp3DAxisFollower();
  ~vtkProp3DAxisFollower() override;

 void CalculateOrthogonalVectors(double Rx[3], double Ry[3], double Rz[3],
                                 vtkAxisActor *axis1, double *dop,
                                 vtkViewport *ren);

 void ComputeRotationAndTranlation(vtkViewport *ren, double translation[3],
                                   double Rx[3], double Ry[3], double Rz[3],
                                   vtkAxisActor *axis);

 // \NOTE: Not used as of now.
 void ComputerAutoCenterTranslation(const double& autoScaleFactor,
                                    double translation[3]);

  int  TestDistanceVisibility();
  void ExecuteViewAngleVisibility(double normal[3]);

  bool IsTextUpsideDown(double* a, double* b);

  int          AutoCenter;

  int          EnableDistanceLOD;
  double       DistanceLODThreshold;

  int          EnableViewAngleLOD;
  double       ViewAngleLODThreshold;

  double       ScreenOffsetVector [2];

  vtkWeakPointer<vtkAxisActor> Axis;
  vtkWeakPointer<vtkViewport> Viewport;
private:
  vtkProp3DAxisFollower(const vtkProp3DAxisFollower&) = delete;
  void operator=(const vtkProp3DAxisFollower&) = delete;

  int TextUpsideDown;
  int VisibleAtCurrentViewAngle;

};

#endif
