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

  Program:   Visualization Toolkit
  Module:    vtkInteractorStyleTrackballCamera.cxx

  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.

=========================================================================*/
#include "vtkInteractorStyleTrackballCamera.h"

#include "vtkCamera.h"
#include "vtkCallbackCommand.h"
#include "vtkMath.h"
#include "vtkObjectFactory.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"

vtkStandardNewMacro(vtkInteractorStyleTrackballCamera);

//----------------------------------------------------------------------------
vtkInteractorStyleTrackballCamera::vtkInteractorStyleTrackballCamera()
{
  this->MotionFactor   = 10.0;
}

//----------------------------------------------------------------------------
vtkInteractorStyleTrackballCamera::~vtkInteractorStyleTrackballCamera() = default;

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnMouseMove()
{
  int x = this->Interactor->GetEventPosition()[0];
  int y = this->Interactor->GetEventPosition()[1];

  switch (this->State)
  {
    case VTKIS_ROTATE:
      this->FindPokedRenderer(x, y);
      this->Rotate();
      this->InvokeEvent(vtkCommand::InteractionEvent, nullptr);
      break;

    case VTKIS_PAN:
      this->FindPokedRenderer(x, y);
      this->Pan();
      this->InvokeEvent(vtkCommand::InteractionEvent, nullptr);
      break;

    case VTKIS_DOLLY:
      this->FindPokedRenderer(x, y);
      this->Dolly();
      this->InvokeEvent(vtkCommand::InteractionEvent, nullptr);
      break;

    case VTKIS_SPIN:
      this->FindPokedRenderer(x, y);
      this->Spin();
      this->InvokeEvent(vtkCommand::InteractionEvent, nullptr);
      break;
  }
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnLeftButtonDown()
{
  this->FindPokedRenderer(this->Interactor->GetEventPosition()[0],
                          this->Interactor->GetEventPosition()[1]);
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  this->GrabFocus(this->EventCallbackCommand);
  if (this->Interactor->GetShiftKey())
  {
    if (this->Interactor->GetControlKey())
    {
      this->StartDolly();
    }
    else
    {
      this->StartPan();
    }
  }
  else
  {
    if (this->Interactor->GetControlKey())
    {
      this->StartSpin();
    }
    else
    {
      this->StartRotate();
    }
  }
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnLeftButtonUp()
{
  switch (this->State)
  {
    case VTKIS_DOLLY:
      this->EndDolly();
      break;

    case VTKIS_PAN:
      this->EndPan();
      break;

    case VTKIS_SPIN:
      this->EndSpin();
      break;

    case VTKIS_ROTATE:
      this->EndRotate();
      break;
  }

  if ( this->Interactor )
  {
    this->ReleaseFocus();
  }
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnMiddleButtonDown()
{
  this->FindPokedRenderer(this->Interactor->GetEventPosition()[0],
                          this->Interactor->GetEventPosition()[1]);
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  this->GrabFocus(this->EventCallbackCommand);
  this->StartPan();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnMiddleButtonUp()
{
  switch (this->State)
  {
    case VTKIS_PAN:
      this->EndPan();
      if ( this->Interactor )
      {
        this->ReleaseFocus();
      }
      break;
  }
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnRightButtonDown()
{
  this->FindPokedRenderer(this->Interactor->GetEventPosition()[0],
                          this->Interactor->GetEventPosition()[1]);
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  this->GrabFocus(this->EventCallbackCommand);
  this->StartDolly();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnRightButtonUp()
{
  switch (this->State)
  {
    case VTKIS_DOLLY:
      this->EndDolly();

      if ( this->Interactor )
      {
        this->ReleaseFocus();
      }
      break;
  }
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnMouseWheelForward()
{
  this->FindPokedRenderer(this->Interactor->GetEventPosition()[0],
                          this->Interactor->GetEventPosition()[1]);
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  this->GrabFocus(this->EventCallbackCommand);
  this->StartDolly();
  double factor = this->MotionFactor * 0.2 * this->MouseWheelMotionFactor;
  this->Dolly(pow(1.1, factor));
  this->EndDolly();
  this->ReleaseFocus();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::OnMouseWheelBackward()
{
  this->FindPokedRenderer(this->Interactor->GetEventPosition()[0],
                          this->Interactor->GetEventPosition()[1]);
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  this->GrabFocus(this->EventCallbackCommand);
  this->StartDolly();
  double factor = this->MotionFactor * -0.2 * this->MouseWheelMotionFactor;
  this->Dolly(pow(1.1, factor));
  this->EndDolly();
  this->ReleaseFocus();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::Rotate()
{
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  vtkRenderWindowInteractor *rwi = this->Interactor;

  int dx = rwi->GetEventPosition()[0] - rwi->GetLastEventPosition()[0];
  int dy = rwi->GetEventPosition()[1] - rwi->GetLastEventPosition()[1];

  int *size = this->CurrentRenderer->GetRenderWindow()->GetSize();

  double delta_elevation = -20.0 / size[1];
  double delta_azimuth = -20.0 / size[0];

  double rxf = dx * delta_azimuth * this->MotionFactor;
  double ryf = dy * delta_elevation * this->MotionFactor;

  vtkCamera *camera = this->CurrentRenderer->GetActiveCamera();
  camera->Azimuth(rxf);
  camera->Elevation(ryf);
  camera->OrthogonalizeViewUp();

  if (this->AutoAdjustCameraClippingRange)
  {
    this->CurrentRenderer->ResetCameraClippingRange();
  }

  if (rwi->GetLightFollowCamera())
  {
    this->CurrentRenderer->UpdateLightsGeometryToFollowCamera();
  }

  rwi->Render();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::Spin()
{
  if ( this->CurrentRenderer == nullptr )
  {
    return;
  }

  vtkRenderWindowInteractor *rwi = this->Interactor;

  double *center = this->CurrentRenderer->GetCenter();

  double newAngle =
    vtkMath::DegreesFromRadians( atan2( rwi->GetEventPosition()[1] - center[1],
                                        rwi->GetEventPosition()[0] - center[0] ) );

  double oldAngle =
    vtkMath::DegreesFromRadians( atan2( rwi->GetLastEventPosition()[1] - center[1],
                                        rwi->GetLastEventPosition()[0] - center[0] ) );

  vtkCamera *camera = this->CurrentRenderer->GetActiveCamera();
  camera->Roll( newAngle - oldAngle );
  camera->OrthogonalizeViewUp();

  rwi->Render();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::Pan()
{
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  vtkRenderWindowInteractor *rwi = this->Interactor;

  double viewFocus[4], focalDepth, viewPoint[3];
  double newPickPoint[4], oldPickPoint[4], motionVector[3];

  // Calculate the focal depth since we'll be using it a lot

  vtkCamera *camera = this->CurrentRenderer->GetActiveCamera();
  camera->GetFocalPoint(viewFocus);
  this->ComputeWorldToDisplay(viewFocus[0], viewFocus[1], viewFocus[2],
                              viewFocus);
  focalDepth = viewFocus[2];

  this->ComputeDisplayToWorld(rwi->GetEventPosition()[0],
                              rwi->GetEventPosition()[1],
                              focalDepth,
                              newPickPoint);

  // Has to recalc old mouse point since the viewport has moved,
  // so can't move it outside the loop

  this->ComputeDisplayToWorld(rwi->GetLastEventPosition()[0],
                              rwi->GetLastEventPosition()[1],
                              focalDepth,
                              oldPickPoint);

  // Camera motion is reversed

  motionVector[0] = oldPickPoint[0] - newPickPoint[0];
  motionVector[1] = oldPickPoint[1] - newPickPoint[1];
  motionVector[2] = oldPickPoint[2] - newPickPoint[2];

  camera->GetFocalPoint(viewFocus);
  camera->GetPosition(viewPoint);
  camera->SetFocalPoint(motionVector[0] + viewFocus[0],
                        motionVector[1] + viewFocus[1],
                        motionVector[2] + viewFocus[2]);

  camera->SetPosition(motionVector[0] + viewPoint[0],
                      motionVector[1] + viewPoint[1],
                      motionVector[2] + viewPoint[2]);

  if (rwi->GetLightFollowCamera())
  {
    this->CurrentRenderer->UpdateLightsGeometryToFollowCamera();
  }

  rwi->Render();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::Dolly()
{
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  vtkRenderWindowInteractor *rwi = this->Interactor;
  double *center = this->CurrentRenderer->GetCenter();
  int dy = rwi->GetEventPosition()[1] - rwi->GetLastEventPosition()[1];
  double dyf = this->MotionFactor * dy / center[1];
  this->Dolly(pow(1.1, dyf));
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::Dolly(double factor)
{
  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  vtkCamera *camera = this->CurrentRenderer->GetActiveCamera();
  if (camera->GetParallelProjection())
  {
    camera->SetParallelScale(camera->GetParallelScale() / factor);
  }
  else
  {
    camera->Dolly(factor);
    if (this->AutoAdjustCameraClippingRange)
    {
      this->CurrentRenderer->ResetCameraClippingRange();
    }
  }

  if (this->Interactor->GetLightFollowCamera())
  {
    this->CurrentRenderer->UpdateLightsGeometryToFollowCamera();
  }

  this->Interactor->Render();
}

//----------------------------------------------------------------------------
void vtkInteractorStyleTrackballCamera::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);
  os << indent << "MotionFactor: " << this->MotionFactor << "\n";
}

