vtkInteractorStyleTerrain.h

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

  Program:   Visualization Toolkit
  Module:    vtkInteractorStyleTerrain.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   vtkInteractorStyleTerrain
 * @brief   manipulate camera in scene with natural view up (e.g., terrain)
 *
 * vtkInteractorStyleTerrain is used to manipulate a camera which is viewing
 * a scene with a natural view up, e.g., terrain. The camera in such a
 * scene is manipulated by specifying azimuth (angle around the view
 * up vector) and elevation (the angle from the horizon).
 *
 * The mouse binding for this class is as follows. Left mouse click followed
 * rotates the camera around the focal point using both elevation and azimuth
 * invocations on the camera. Left mouse motion in the horizontal direction
 * results in azimuth motion; left mouse motion in the vertical direction
 * results in elevation motion. Therefore, diagonal motion results in a
 * combination of azimuth and elevation. (If the shift key is held during
 * motion, then only one of elevation or azimuth is invoked, depending on the
 * whether the mouse motion is primarily horizontal or vertical.) Middle
 * mouse button pans the camera across the scene (again the shift key has a
 * similar effect on limiting the motion to the vertical or horizontal
 * direction. The right mouse is used to dolly (e.g., a type of zoom) towards
 * or away from the focal point.
 *
 * The class also supports some keypress events. The "r" key resets the
 * camera.  The "e" key invokes the exit callback and by default exits the
 * program. The "f" key sets a new camera focal point and flys towards that
 * point. The "u" key invokes the user event. The "3" key toggles between
 * stereo and non-stero mode. The "l" key toggles on/off a latitude/longitude
 * markers that can be used to estimate/control position.
 *
 *
 * @sa
 * vtkInteractorObserver vtkInteractorStyle vtk3DWidget
*/

#ifndef vtkInteractorStyleTerrain_h
#define vtkInteractorStyleTerrain_h

#include "vtkInteractionStyleModule.h" // For export macro
#include "vtkInteractorStyle.h"

class vtkPolyDataMapper;
class vtkSphereSource;
class vtkExtractEdges;

class VTKINTERACTIONSTYLE_EXPORT vtkInteractorStyleTerrain : public vtkInteractorStyle
{
public:
  /**
   * Instantiate the object.
   */
  static vtkInteractorStyleTerrain *New();

  vtkTypeMacro(vtkInteractorStyleTerrain,vtkInteractorStyle);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  //@{
  /**
   * Event bindings controlling the effects of pressing mouse buttons
   * or moving the mouse.
   */
  void OnMouseMove() override;
  void OnLeftButtonDown() override;
  void OnLeftButtonUp() override;
  void OnMiddleButtonDown() override;
  void OnMiddleButtonUp() override;
  void OnRightButtonDown() override;
  void OnRightButtonUp() override;
  //@}

  /**
   * Override the "fly-to" (f keypress) for images.
   */
  void OnChar() override;

  // These methods for the different interactions in different modes
  // are overridden in subclasses to perform the correct motion.
  void Rotate() override;
  void Pan() override;
  void Dolly() override;

  //@{
  /**
   * Turn on/off the latitude/longitude lines.
   */
  vtkSetMacro(LatLongLines,int);
  vtkGetMacro(LatLongLines,int);
  vtkBooleanMacro(LatLongLines,int);
  //@}

protected:
  vtkInteractorStyleTerrain();
  ~vtkInteractorStyleTerrain() override;

  // Internal helper attributes
  int LatLongLines;

  vtkSphereSource *LatLongSphere;
  vtkPolyDataMapper *LatLongMapper;
  vtkActor *LatLongActor;
  vtkExtractEdges *LatLongExtractEdges;

  void SelectRepresentation();
  void CreateLatLong();

  double MotionFactor;

private:
  vtkInteractorStyleTerrain(const vtkInteractorStyleTerrain&) = delete;
  void operator=(const vtkInteractorStyleTerrain&) = delete;

};

#endif