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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkRenderWindow.cxx,v $

  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 "vtkRenderWindow.h"

#include "vtkCamera.h"
#include "vtkCommand.h"
#include "vtkGraphicsFactory.h"
#include "vtkMath.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRendererCollection.h"
#include "vtkTransform.h"

vtkCxxRevisionMacro(vtkRenderWindow, "$Revision: 1.144 $");

//----------------------------------------------------------------------------
// Needed when we don't use the vtkStandardNewMacro.
vtkInstantiatorNewMacro(vtkRenderWindow);
//----------------------------------------------------------------------------

// Construct an instance of  vtkRenderWindow with its screen size 
// set to 300x300, borders turned on, positioned at (0,0), double 
// buffering turned on, stereo capable off.
vtkRenderWindow::vtkRenderWindow()
{
  this->IsPicking = 0;
  this->Borders = 1;
  this->FullScreen = 0;
  this->OldScreen[0] = this->OldScreen[1] = 0;
  this->OldScreen[2] = this->OldScreen[3] = 300;
  this->OldScreen[4] = 1;
  this->DoubleBuffer = 1;
  this->PointSmoothing = 0;
  this->LineSmoothing = 0;
  this->PolygonSmoothing = 0;
  this->StereoRender = 0;
  this->StereoType = VTK_STEREO_RED_BLUE;
  this->StereoStatus = 0;
  this->StereoCapableWindow = 0;
  this->AlphaBitPlanes = 0;
  this->Interactor = NULL;
  this->AAFrames = 0;
  this->FDFrames = 0;
  this->SubFrames = 0;
  this->AccumulationBuffer = NULL;
  this->AccumulationBufferSize = 0;
  this->CurrentSubFrame = 0;
  this->DesiredUpdateRate = 0.0001;
  this->ResultFrame = NULL;
  this->SwapBuffers = 1;
  this->AbortRender = 0;
  this->InAbortCheck = 0;
  this->InRender = 0;
  this->NeverRendered = 1;
  this->Renderers = vtkRendererCollection::New();
  this->NumberOfLayers = 1;
  this->CurrentCursor = VTK_CURSOR_DEFAULT;
  this->AnaglyphColorSaturation = 0.65;
  this->AnaglyphColorMask[0] = 4;  // red
  this->AnaglyphColorMask[1] = 3;  // cyan
}

vtkRenderWindow::~vtkRenderWindow()
{
  this->SetInteractor(NULL);
  
  if (this->AccumulationBuffer) 
    {
    delete [] this->AccumulationBuffer;
    this->AccumulationBuffer = NULL;
    this->AccumulationBufferSize = 0;
    }
  if (this->ResultFrame) 
    {
    delete [] this->ResultFrame;
    this->ResultFrame = NULL;
    }
  this->Renderers->Delete();
}

// return the correct type of RenderWindow 
vtkRenderWindow *vtkRenderWindow::New()
{
  // First try to create the object from the vtkObjectFactory
  vtkObject* ret = vtkGraphicsFactory::CreateInstance("vtkRenderWindow");
  return (vtkRenderWindow*)ret;
}

// Create an interactor that will work with this renderer.
vtkRenderWindowInteractor *vtkRenderWindow::MakeRenderWindowInteractor()
{
  this->Interactor = vtkRenderWindowInteractor::New();
  this->Interactor->SetRenderWindow(this);
  return this->Interactor;
}

// Set the interactor that will work with this renderer.
void vtkRenderWindow::SetInteractor(vtkRenderWindowInteractor *rwi)
{
  if (this->Interactor != rwi)
    {
    // to avoid destructor recursion
    vtkRenderWindowInteractor *temp = this->Interactor;
    this->Interactor = rwi;    
    if (temp != NULL) {temp->UnRegister(this);}
    if (this->Interactor != NULL) 
      {
      this->Interactor->Register(this);
      if (this->Interactor->GetRenderWindow() != this)
        {
        this->Interactor->SetRenderWindow(this);
        }
      }
    }
}

void vtkRenderWindow::SetSubFrames(int subFrames)
{
  if (this->SubFrames != subFrames)
    {
    this->SubFrames = subFrames;
    if (this->CurrentSubFrame >= this->SubFrames)
      {
      this->CurrentSubFrame = 0;
      }
    vtkDebugMacro(<< this->GetClassName() << " (" << this << "): setting SubFrames to " << subFrames);
    this->Modified();
    }
}

void vtkRenderWindow::SetDesiredUpdateRate(double rate)
{
  vtkRenderer *aren;

  if (this->DesiredUpdateRate != rate)
    {
    vtkCollectionSimpleIterator rsit;
    for (this->Renderers->InitTraversal(rsit); 
         (aren = this->Renderers->GetNextRenderer(rsit)); )
      {
      aren->SetAllocatedRenderTime(1.0/
                                   (rate*this->Renderers->GetNumberOfItems()));
      }
    this->DesiredUpdateRate = rate;
    this->Modified();
    }
}


//
// Set the variable that indicates that we want a stereo capable window
// be created. This method can only be called before a window is realized.
//
void vtkRenderWindow::SetStereoCapableWindow(int capable)
{
  if (this->StereoCapableWindow != capable)
    {
    this->StereoCapableWindow = capable;
    this->Modified();
    }
}

// Turn on stereo rendering
void vtkRenderWindow::SetStereoRender(int stereo)
{
  if (stereo == this->StereoRender)
    {
    return;
    }
  
  if (this->StereoCapableWindow ||
      (!this->StereoCapableWindow
       && this->StereoType != VTK_STEREO_CRYSTAL_EYES))
    {
    if (stereo != this->StereoRender)
      {
      this->StereoRender = stereo;
      this->Modified();
      }
    }
  else
    {
    vtkWarningMacro(<< "Adjusting stereo mode on a window that does not "
    << "support stereo type " << this->GetStereoTypeAsString()
    << " is not possible.");
    }
}



// Ask each renderer owned by this RenderWindow to render its image and 
// synchronize this process.
void vtkRenderWindow::Render()
{
  int *size;
  int x,y;
  float *p1;

  // if we are in the middle of an abort check then return now
  if (this->InAbortCheck)
    {
    return;
    }

  // if we are in a render already from somewhere else abort now
  if (this->InRender)
    {
    return;
    }

  // reset the Abort flag
  this->AbortRender = 0;
  this->InRender = 1;

  vtkDebugMacro(<< "Starting Render Method.\n");
  this->InvokeEvent(vtkCommand::StartEvent,NULL);

  this->NeverRendered = 0;

  if ( this->Interactor && ! this->Interactor->GetInitialized() )
    {
    this->Interactor->Initialize();
    }
  
  // if there is a reason for an AccumulationBuffer
  if ( this->SubFrames || this->AAFrames || this->FDFrames)
    {
    // check the current size
    size = this->GetSize();
    unsigned int bufferSize = 3*size[0]*size[1];
    // If there is not a buffer or the size is too small
    // re-allocate it
    if( !this->AccumulationBuffer 
        || bufferSize > this->AccumulationBufferSize)
      {
      // it is OK to delete null, no sense in two if's
      delete [] this->AccumulationBuffer;
      // Save the size of the buffer
      this->AccumulationBufferSize = 3*size[0]*size[1];
      this->AccumulationBuffer = new float [this->AccumulationBufferSize];
      memset(this->AccumulationBuffer,0,this->AccumulationBufferSize*sizeof(float));
      }
    }
  
  // handle any sub frames
  if (this->SubFrames)
    {
    // get the size
    size = this->GetSize();

    // draw the images
    this->DoAARender();

    // now accumulate the images 
    if ((!this->AAFrames) && (!this->FDFrames))
      {
      p1 = this->AccumulationBuffer;
      unsigned char *p2;
      unsigned char *p3;
      if (this->ResultFrame)
        {
        p2 = this->ResultFrame;
        }
      else
        {
        p2 = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
        }
      p3 = p2;
      for (y = 0; y < size[1]; y++)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p1 += *p2; p1++; p2++;
          *p1 += *p2; p1++; p2++;
          *p1 += *p2; p1++; p2++;
          }
        }
      delete [] p3;
      }
    
    // if this is the last sub frame then convert back into unsigned char
    this->CurrentSubFrame++;
    if (this->CurrentSubFrame >= this->SubFrames)
      {
      double num;
      unsigned char *p2 = new unsigned char [3*size[0]*size[1]];
      
      num = this->SubFrames;
      if (this->AAFrames)
        {
        num *= this->AAFrames;
        }
      if (this->FDFrames)
        {
        num *= this->FDFrames;
        }

      this->ResultFrame = p2;
      p1 = this->AccumulationBuffer;
      for (y = 0; y < size[1]; y++)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          }
        }
      
      this->CurrentSubFrame = 0;
      this->CopyResultFrame();

      // free any memory
      delete [] this->AccumulationBuffer;
      this->AccumulationBuffer = NULL;
      }
    }
  else // no subframes
    {
    // get the size
    size = this->GetSize();

    this->DoAARender();
    // if we had some accumulation occur
    if (this->AccumulationBuffer)
      {
      double num;
      unsigned char *p2 = new unsigned char [3*size[0]*size[1]];

      if (this->AAFrames) 
        {
        num = this->AAFrames;
        }
      else
        {
        num = 1;
        }
      if (this->FDFrames)
        {
        num *= this->FDFrames;
        }

      this->ResultFrame = p2;
      p1 = this->AccumulationBuffer;
      for (y = 0; y < size[1]; y++)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          *p2 = (unsigned char)(*p1/num); p1++; p2++;
          }
        }
      
      delete [] this->AccumulationBuffer;
      this->AccumulationBuffer = NULL;
      }
    
    this->CopyResultFrame();
    }  

  if (this->ResultFrame) 
    {
    delete [] this->ResultFrame;
    this->ResultFrame = NULL;
    }

  this->InRender = 0;
  this->InvokeEvent(vtkCommand::EndEvent,NULL);  
}

// Handle rendering any antialiased frames.
void vtkRenderWindow::DoAARender()
{
  int i;
  
  // handle any anti aliasing
  if (this->AAFrames)
    {
    int *size;
    int x,y;
    float *p1;
    vtkRenderer *aren;
    vtkCamera *acam;
    double *dpoint;
    double offsets[2];
    double origfocus[4];
    double worldOffset[3];

    // get the size
    size = this->GetSize();

    origfocus[3] = 1.0;

    for (i = 0; i < this->AAFrames; i++)
      {
      // jitter the cameras
      offsets[0] = vtkMath::Random() - 0.5;
      offsets[1] = vtkMath::Random() - 0.5;

      vtkCollectionSimpleIterator rsit;
      for (this->Renderers->InitTraversal(rsit); 
           (aren = this->Renderers->GetNextRenderer(rsit)); )
        {
        acam = aren->GetActiveCamera();

        // calculate the amount to jitter
        acam->GetFocalPoint(origfocus);
        aren->SetWorldPoint(origfocus);
        aren->WorldToDisplay();
        dpoint = aren->GetDisplayPoint();
        aren->SetDisplayPoint(dpoint[0] + offsets[0],
                              dpoint[1] + offsets[1],
                              dpoint[2]);
        aren->DisplayToWorld();
        dpoint = aren->GetWorldPoint();
        dpoint[0] /= dpoint[3];
        dpoint[1] /= dpoint[3];
        dpoint[2] /= dpoint[3];
        acam->SetFocalPoint(dpoint);

        worldOffset[0] = dpoint[0] - origfocus[0];
        worldOffset[1] = dpoint[1] - origfocus[1];
        worldOffset[2] = dpoint[2] - origfocus[2];

        acam->GetPosition(dpoint);
        acam->SetPosition(dpoint[0]+worldOffset[0],
                          dpoint[1]+worldOffset[1],
                          dpoint[2]+worldOffset[2]);
        }

      // draw the images
      this->DoFDRender();
      
      // restore the jitter to normal
      for (this->Renderers->InitTraversal(rsit); 
           (aren = this->Renderers->GetNextRenderer(rsit)); )
        {
        acam = aren->GetActiveCamera();

        // calculate the amount to jitter
        acam->GetFocalPoint(origfocus);
        aren->SetWorldPoint(origfocus);
        aren->WorldToDisplay();
        dpoint = aren->GetDisplayPoint();
        aren->SetDisplayPoint(dpoint[0] - offsets[0],
                              dpoint[1] - offsets[1],
                              dpoint[2]);
        aren->DisplayToWorld();
        dpoint = aren->GetWorldPoint();
        dpoint[0] /= dpoint[3];
        dpoint[1] /= dpoint[3];
        dpoint[2] /= dpoint[3];
        acam->SetFocalPoint(dpoint);

        worldOffset[0] = dpoint[0] - origfocus[0];
        worldOffset[1] = dpoint[1] - origfocus[1];
        worldOffset[2] = dpoint[2] - origfocus[2];

        acam->GetPosition(dpoint);
        acam->SetPosition(dpoint[0]+worldOffset[0],
                          dpoint[1]+worldOffset[1],
                          dpoint[2]+worldOffset[2]);
        }


      // now accumulate the images 
      p1 = this->AccumulationBuffer;
      if (!this->FDFrames)
        {
        unsigned char *p2;
        unsigned char *p3;
        if (this->ResultFrame)
          {
          p2 = this->ResultFrame;
          }
        else
          {
          p2 = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
          }
        p3 = p2;
        for (y = 0; y < size[1]; y++)
          {
          for (x = 0; x < size[0]; x++)
            {
            *p1 += (float)*p2; p1++; p2++;
            *p1 += (float)*p2; p1++; p2++;
            *p1 += (float)*p2; p1++; p2++;
            }
          }
        delete [] p3;
        }
      }
    }
  else
    {
    this->DoFDRender();
    }
}


// Handle rendering any focal depth frames.
void vtkRenderWindow::DoFDRender()
{
  int i;
  
  // handle any focal depth
  if (this->FDFrames)
    {
    int *size;
    int x,y;
    unsigned char *p2;
    unsigned char *p3;
    float *p1;
    vtkRenderer *aren;
    vtkCamera *acam;
    double focalDisk;
    double *vpn, *dpoint;
    double vec[3];
    vtkTransform *aTrans = vtkTransform::New();
    double offsets[2];
    double *orig;
    vtkCollectionSimpleIterator rsit;

    // get the size
    size = this->GetSize();

    orig = new double [3*this->Renderers->GetNumberOfItems()];

    for (i = 0; i < this->FDFrames; i++)
      {
      int j = 0;

      offsets[0] = vtkMath::Random(); // radius
      offsets[1] = vtkMath::Random()*360.0; // angle

      // store offsets for each renderer 
      for (this->Renderers->InitTraversal(rsit); 
           (aren = this->Renderers->GetNextRenderer(rsit)); )
        {
        acam = aren->GetActiveCamera();
        focalDisk = acam->GetFocalDisk()*offsets[0];

        vpn = acam->GetViewPlaneNormal();
        aTrans->Identity();
        aTrans->Scale(focalDisk,focalDisk,focalDisk);
        aTrans->RotateWXYZ(-offsets[1],vpn[0],vpn[1],vpn[2]);
        aTrans->TransformVector(acam->GetViewUp(),vec);

        dpoint = acam->GetPosition();

        // store the position for later
        memcpy(orig + j*3,dpoint,3 * sizeof (double));
        j++;

        acam->SetPosition(dpoint[0]+vec[0],
                          dpoint[1]+vec[1],
                          dpoint[2]+vec[2]);
        }

      // draw the images
      this->DoStereoRender();

      // restore the jitter to normal
      j = 0;
      for (this->Renderers->InitTraversal(rsit); 
           (aren = this->Renderers->GetNextRenderer(rsit)); )
        {
        acam = aren->GetActiveCamera();
        acam->SetPosition(orig + j*3);
        j++;
        }

      // get the pixels for accumulation
      // now accumulate the images 
      p1 = this->AccumulationBuffer;
      if (this->ResultFrame)
        {
        p2 = this->ResultFrame;
        }
      else
        {
        p2 = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
        }
      p3 = p2;
      for (y = 0; y < size[1]; y++)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p1 += (float)*p2; p1++; p2++;
          *p1 += (float)*p2; p1++; p2++;
          *p1 += (float)*p2; p1++; p2++;
          }
        }
      delete [] p3;
      }
  
    // free memory
    delete [] orig;
    aTrans->Delete();
    }
  else
    {
    this->DoStereoRender();
    }
}


// Handle rendering the two different views for stereo rendering.
void vtkRenderWindow::DoStereoRender()
{
  this->Start();
  this->StereoUpdate();
  if (this->StereoType != VTK_STEREO_RIGHT)
    { // render the left eye
    this->Renderers->Render();
    }

  if (this->StereoRender)
    {
    this->StereoMidpoint();
    if (this->StereoType != VTK_STEREO_LEFT)
      { // render the right eye
      this->Renderers->Render();
      }
    this->StereoRenderComplete();
    }
}

// Add a renderer to the list of renderers.
void vtkRenderWindow::AddRenderer(vtkRenderer *ren)
{
  if (this->HasRenderer(ren))
    {
    return;
    }
  // we are its parent
  this->MakeCurrent();
  ren->SetRenderWindow(this);
  this->Renderers->AddItem(ren);
  vtkRenderer *aren;
  vtkCollectionSimpleIterator rsit;

  for (this->Renderers->InitTraversal(rsit); 
       (aren = this->Renderers->GetNextRenderer(rsit)); )
    {
    aren->SetAllocatedRenderTime
      (1.0/(this->DesiredUpdateRate*this->Renderers->GetNumberOfItems()));
    }
}

// Remove a renderer from the list of renderers.
void vtkRenderWindow::RemoveRenderer(vtkRenderer *ren)
{
  // we are its parent 
  this->Renderers->RemoveItem(ren);
}

int vtkRenderWindow::HasRenderer(vtkRenderer *ren)
{
  return (ren && this->Renderers->IsItemPresent(ren));
}

int vtkRenderWindow::CheckAbortStatus()
{
  if (!this->InAbortCheck)
    {
    this->InAbortCheck = 1;
    this->InvokeEvent(vtkCommand::AbortCheckEvent,NULL);
    this->InAbortCheck = 0;
    }
  return this->AbortRender;
}

void vtkRenderWindow::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "Borders: " << (this->Borders ? "On\n":"Off\n");
  os << indent << "IsPicking: " << (this->IsPicking ? "On\n":"Off\n");
  os << indent << "Double Buffer: " << (this->DoubleBuffer ? "On\n":"Off\n");
  os << indent << "Full Screen: " << (this->FullScreen ? "On\n":"Off\n");
  os << indent << "Renderers:\n";
  this->Renderers->PrintSelf(os,indent.GetNextIndent());
  os << indent << "Stereo Capable Window Requested: " 
     << (this->StereoCapableWindow ? "Yes\n":"No\n");
  os << indent << "Stereo Render: " 
     << (this->StereoRender ? "On\n":"Off\n");

  os << indent << "Point Smoothing: " 
     << (this->PointSmoothing ? "On\n":"Off\n");
  os << indent << "Line Smoothing: " 
     << (this->LineSmoothing ? "On\n":"Off\n");
  os << indent << "Polygon Smoothing: " 
     << (this->PolygonSmoothing ? "On\n":"Off\n");
  os << indent << "Anti Aliased Frames: " << this->AAFrames << "\n";
  os << indent << "Abort Render: " << this->AbortRender << "\n";
  os << indent << "Current Cursor: " << this->CurrentCursor << "\n";
  os << indent << "Desired Update Rate: " << this->DesiredUpdateRate << "\n";
  os << indent << "Focal Depth Frames: " << this->FDFrames << "\n";
  os << indent << "In Abort Check: " << this->InAbortCheck << "\n";
  os << indent << "NeverRendered: " << this->NeverRendered << "\n";
  os << indent << "Interactor: " << this->Interactor << "\n";
  os << indent << "Motion Blur Frames: " << this->SubFrames << "\n";
  os << indent << "Swap Buffers: " << (this->SwapBuffers ? "On\n":"Off\n");
  os << indent << "Stereo Type: " << this->GetStereoTypeAsString() << "\n";
  os << indent << "Number of Layers: " << this->NumberOfLayers << "\n";
  os << indent << "AccumulationBuffer Size " << this->AccumulationBufferSize << "\n";
  os << indent << "AlphaBitPlanes: " << (this->AlphaBitPlanes ? "On" : "Off")
     << endl;
  
  os << indent << "AnaglyphColorSaturation: " 
     << this->AnaglyphColorSaturation << "\n";
  os << indent << "AnaglyphColorMask: "  
     << this->AnaglyphColorMask[0] << " , " 
     << this->AnaglyphColorMask[1] << "\n";
}


// Update the system, if needed, due to stereo rendering. For some stereo 
// methods, subclasses might need to switch some hardware settings here.
void vtkRenderWindow::StereoUpdate(void)
{
  // if stereo is on and it wasn't before
  if (this->StereoRender && (!this->StereoStatus))
    {
    switch (this->StereoType) 
      {
      case VTK_STEREO_RED_BLUE:
        this->StereoStatus = 1;
        break;
      case VTK_STEREO_ANAGLYPH:
        this->StereoStatus = 1;
        break;
      case VTK_STEREO_DRESDEN:
        this->StereoStatus = 1;
        break;      
      case VTK_STEREO_INTERLACED:
        this->StereoStatus = 1;
      }
    }
  else if ((!this->StereoRender) && this->StereoStatus)
    {
    switch (this->StereoType) 
      {
      case VTK_STEREO_RED_BLUE:
        this->StereoStatus = 0;
        break;
      case VTK_STEREO_ANAGLYPH:
        this->StereoStatus = 0;
        break;
      case VTK_STEREO_DRESDEN:
        this->StereoStatus = 0;
        break;
      case VTK_STEREO_INTERLACED:
        this->StereoStatus = 0;
        break;
      }
    }
}

// Intermediate method performs operations required between the rendering
// of the left and right eye.
void vtkRenderWindow::StereoMidpoint(void)
{
  vtkRenderer * aren;
  /* For IceT stereo */
  for (Renderers->InitTraversal() ; (aren = Renderers->GetNextItem()) ; ) 
    {
    aren->StereoMidpoint();
    }
  if ((this->StereoType == VTK_STEREO_RED_BLUE) ||
      (this->StereoType == VTK_STEREO_INTERLACED) ||
      (this->StereoType == VTK_STEREO_DRESDEN) ||
      (this->StereoType == VTK_STEREO_ANAGLYPH))
    {
    int *size;
    // get the size
    size = this->GetSize();
    // get the data
    this->StereoBuffer = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
    }
}

// Handles work required once both views have been rendered when using
// stereo rendering.
void vtkRenderWindow::StereoRenderComplete(void)
{
  switch (this->StereoType) 
    {
    case VTK_STEREO_RED_BLUE:
      {
      unsigned char *buff;
      unsigned char *p1, *p2, *p3;
      unsigned char* result;
      int *size;
      int x,y;
      int res;

      // get the size
      size = this->GetSize();
      // get the data
      buff = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
      p1 = this->StereoBuffer;
      p2 = buff;

      // allocate the result
      result = new unsigned char [size[0]*size[1]*3];
      if (!result)
        {
        vtkErrorMacro(<<"Couldn't allocate memory for RED BLUE stereo.");
        return;
        }
      p3 = result;

      // now merge the two images 
      for (x = 0; x < size[0]; x++)
        {
        for (y = 0; y < size[1]; y++)
          {
          res = p1[0] + p1[1] + p1[2];
          p3[0] = res/3;
          res = p2[0] + p2[1] + p2[2];
          p3[1] = 0;
          p3[2] = res/3;
          
          p1 += 3;
          p2 += 3;
          p3 += 3;
          }
        }
      this->ResultFrame = result;
      delete [] this->StereoBuffer;
      this->StereoBuffer = NULL;
      delete [] buff;
      }
      break;
    case VTK_STEREO_ANAGLYPH:
      {
      unsigned char *buff;
      unsigned char *p0, *p1, *p2;
      unsigned char* result;
      int *size;
      int x,y;
      int m0, m1, ave0, ave1;
      int avecolor[256][3], satcolor[256];
      float a;

      // get the size
      size = this->GetSize();
      // get the data
      buff = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
      p0 = this->StereoBuffer;
      p1 = buff;

      // allocate the result
      result = new unsigned char [size[0]*size[1]*3];
      if (!result)
        {
        vtkErrorMacro(<<"Couldn't allocate memory for ANAGLYPH stereo.");
        return;
        }
      p2 = result;

      // build some tables
      a = this->AnaglyphColorSaturation;
      m0 = this->AnaglyphColorMask[0];
      m1 = this->AnaglyphColorMask[1];

      for(x = 0; x < 256; x++) 
        {
        avecolor[x][0] = int((1.0-a)*x*0.3086);
        avecolor[x][1] = int((1.0-a)*x*0.6094);
        avecolor[x][2] = int((1.0-a)*x*0.0820);

        satcolor[x] = int(a*x);
        }

      // now merge the two images 
      for (x = 0; x < size[0]; x++)
        {
        for (y = 0; y < size[1]; y++)
          {
            ave0 = avecolor[p0[0]][0] + avecolor[p0[1]][1] + avecolor[p0[2]][2];
            ave1 = avecolor[p1[0]][0] + avecolor[p1[1]][1] + avecolor[p1[2]][2];
            if (m0 & 0x4) 
              {
              p2[0] = satcolor[p0[0]] + ave0;
              }
            if (m0 & 0x2) 
              {
              p2[1] = satcolor[p0[1]] + ave0;
              }
            if (m0 & 0x1) 
              {
              p2[2] = satcolor[p0[2]] + ave0;
              }
            if (m1 & 0x4) 
              {
              p2[0] = satcolor[p1[0]] + ave1;
              }
            if (m1 & 0x2) 
              {
              p2[1] = satcolor[p1[1]] + ave1;
              }
            if (m1 & 0x1) 
              {
              p2[2] = satcolor[p1[2]] + ave1;
              }
            p0 += 3;
            p1 += 3;
            p2 += 3;
          }
        }
      this->ResultFrame = result;
      delete [] this->StereoBuffer;
      this->StereoBuffer = NULL;
      delete [] buff;
      }
      break;
    case VTK_STEREO_INTERLACED:
      {
      unsigned char *buff;
      unsigned char *p1, *p2, *p3;
      unsigned char* result;
      int *size, line;
      int x,y;

      // get the size
      size = this->GetSize();
      // get the data
      buff = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
      p1 = this->StereoBuffer;
      p2 = buff;
      line = size[0] * 3;

      // allocate the result
      result = new unsigned char [size[0]*size[1]*3];
      if (!result)
        {
        vtkErrorMacro(<<"Couldn't allocate memory for interlaced stereo.");
        return;
        }

      // now merge the two images 
      p3 = result;
      for (y = 0; y < size[1]; y += 2)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p3++ = *p1++;
          *p3++ = *p1++;
          *p3++ = *p1++;
          }
        // skip a line
        p3 += line;
        p1 += line;
        }
      // now the other eye
      p3 = result + line;
      p2 += line;
      for (y = 1; y < size[1]; y += 2)
        {
        for (x = 0; x < size[0]; x++)
          {
          *p3++ = *p2++;
          *p3++ = *p2++;
          *p3++ = *p2++;
          }
        // skip a line
        p3 += line;
        p2 += line;
        }

      this->ResultFrame = result;
      delete [] this->StereoBuffer;
      this->StereoBuffer = NULL;
      delete [] buff;
      }
      break;
      
    case VTK_STEREO_DRESDEN:
      {
      unsigned char *buff;
      unsigned char *p1, *p2, *p3;
      unsigned char* result;
      int *size;
      int x,y;
      
      // get the size
      size = this->GetSize();
      // get the data
      buff = this->GetPixelData(0,0,size[0]-1,size[1]-1,!this->DoubleBuffer);
      p1 = this->StereoBuffer;
      p2 = buff;
      
      // allocate the result
      result = new unsigned char [size[0]*size[1]*3];
      if (!result) 
        {
        vtkErrorMacro(
          <<"Couldn't allocate memory for dresden display stereo.");
        return;
        }
      
      // now merge the two images 
      p3 = result;
      
      for (y = 0; y < size[1]; y++ ) 
        {
        for (x = 0; x < size[0]; x+=2) 
          {
          *p3++ = *p1++;
          *p3++ = *p1++;
          *p3++ = *p1++;
          
          p3+=3;
          p1+=3;
          }
        if( size[0] % 2 == 1 ) 
          {
          p3 -= 3;
          p1 -= 3;
          }
        }
      
      // now the other eye
      p3 = result + 3;
      p2 += 3;
      
      for (y = 0; y < size[1]; y++) 
        {
        for (x = 1; x < size[0]; x+=2) 
          {
          *p3++ = *p2++;
          *p3++ = *p2++;
          *p3++ = *p2++;
          
          p3+=3;
          p2+=3;
          }
        if( size[0] % 2 == 1 ) 
          {
          p3 += 3;
          p2 += 3;
          }
        }
      
      this->ResultFrame = result;
      delete [] this->StereoBuffer;
      this->StereoBuffer = NULL;
      delete [] buff;
      }
      break;
    }
}


void vtkRenderWindow::CopyResultFrame(void)
{
  if (this->ResultFrame)
    {
    int *size;

    // get the size
    size = this->GetSize();
    this->SetPixelData(0,0,size[0]-1,size[1]-1,this->ResultFrame,!this->DoubleBuffer);
    }

  this->Frame();
}


// treat renderWindow and interactor as one object.
// it might be easier if the GetReference count method were redefined.
void vtkRenderWindow::UnRegister(vtkObjectBase *o)
{
  if (this->Interactor && this->Interactor->GetRenderWindow() == this &&
      this->Interactor != o)
    {
    if (this->GetReferenceCount() + this->Interactor->GetReferenceCount() == 3)
      {
      this->vtkObject::UnRegister(o);
      vtkRenderWindowInteractor *tmp = this->Interactor;
      tmp->Register(0);
      this->Interactor->SetRenderWindow(NULL);
      tmp->UnRegister(0);
      return;
      }
    }
  
  this->vtkObject::UnRegister(o);
}

const char *vtkRenderWindow::GetRenderLibrary() 
{
  return vtkGraphicsFactory::GetRenderLibrary();
}