Method OnRotate

Interaction/Style/vtkInteractorStyleMultiTouchCamera.cxx:31–83

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//------------------------------------------------------------------------------
void vtkInteractorStyleMultiTouchCamera::OnRotate()
{
  if (this->State != VTKIS_GESTURE)
  {
    return;
  }

  int pointer = this->Interactor->GetPointerIndex();

  this->FindPokedRenderer(this->Interactor->GetEventPositions(pointer)[0],
    this->Interactor->GetEventPositions(pointer)[1]);

  if (this->CurrentRenderer == nullptr)
  {
    return;
  }

  vtkCamera* camera = this->CurrentRenderer->GetActiveCamera();

  int* pinchPositionDisplay = this->Interactor->GetEventPositions(pointer);

  // Calculate the focal depth since we'll be using it a lot
  double viewFocus[4];
  camera->GetFocalPoint(viewFocus);
  this->ComputeWorldToDisplay(viewFocus[0], viewFocus[1], viewFocus[2], viewFocus);
  double focalDepth = viewFocus[2];

  double oldPickPoint[4] = { 0, 0, 0, 0 };
  vtkInteractorObserver::ComputeDisplayToWorld(this->CurrentRenderer, pinchPositionDisplay[0],
    pinchPositionDisplay[1], focalDepth, oldPickPoint);

  camera->Roll(this->Interactor->GetRotation() - this->Interactor->GetLastRotation());

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

  double newPickPoint[4] = { 0, 0, 0, 0 };
  vtkInteractorObserver::ComputeDisplayToWorld(this->CurrentRenderer, pinchPositionDisplay[0],
    pinchPositionDisplay[1], focalDepth, newPickPoint);

  double motionVector[3] = { 0, 0, 0 };
  vtkMath::Subtract(oldPickPoint, newPickPoint, motionVector);

  vtkNew<vtkTransform> cameraTransform;
  cameraTransform->Identity();
  cameraTransform->Translate(motionVector);
  camera->ApplyTransform(cameraTransform);

  camera->OrthogonalizeViewUp();

  this->Interactor->Render();
}

//------------------------------------------------------------------------------
void vtkInteractorStyleMultiTouchCamera::OnEndRotate()