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

Program:   Visualization Toolkit
Module:    vtkWin32OpenGLRenderWindow.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 "vtkWin32OpenGLRenderWindow.h"

#include "vtkIdList.h"
#include "vtkCommand.h"
#include "vtkObjectFactory.h"
#include "vtkOpenGLActor.h"
#include "vtkOpenGLCamera.h"
#include "vtkOpenGLLight.h"
#include "vtkOpenGLPolyDataMapper.h"
#include "vtkOpenGLProperty.h"
#include "vtkOpenGLRenderer.h"
#include "vtkOpenGLTexture.h"
#include "vtkRendererCollection.h"
#include "vtkWin32RenderWindowInteractor.h"

#include <math.h>
#include <vtksys/ios/sstream>

#include "vtkOpenGL.h"

vtkStandardNewMacro(vtkWin32OpenGLRenderWindow);

#define VTK_MAX_LIGHTS 8

vtkWin32OpenGLRenderWindow::vtkWin32OpenGLRenderWindow()
{
  this->ApplicationInstance =  NULL;
  this->Palette = NULL;
  this->ContextId = 0;
  this->MultiSamples = 8;
  this->WindowId = 0;
  this->ParentId = 0;
  this->NextWindowId = 0;
  this->DeviceContext = (HDC)0;         // hsr
  this->MFChandledWindow = FALSE;       // hsr
  this->StereoType = VTK_STEREO_CRYSTAL_EYES;
  this->CursorHidden = 0;
  this->Capabilities = 0;

  this->ScreenDeviceContext = (HDC)0;
  this->MemoryHdc = (HDC)0;
  this->CreatingOffScreenWindow = 0;
  this->WindowIdReferenceCount = 0;
}

vtkWin32OpenGLRenderWindow::~vtkWin32OpenGLRenderWindow()
{
  this->Finalize();
  
  vtkRenderer *ren;
  vtkCollectionSimpleIterator rsit;
  for (this->Renderers->InitTraversal(rsit); 
       (ren = this->Renderers->GetNextRenderer(rsit));)
    {
    ren->SetRenderWindow(NULL);
    }

  delete[] this->Capabilities;
}

void vtkWin32OpenGLRenderWindow::Clean()
{
  GLuint id;
  
  /* finish OpenGL rendering */
  if (this->ContextId) 
    {
    this->MakeCurrent();

    /* first delete all the old lights */
    for (short cur_light = GL_LIGHT0; cur_light < GL_LIGHT0+VTK_MAX_LIGHTS; cur_light++)
      {
      glDisable((GLenum)cur_light);
      }
    
    /* now delete all textures */
    glDisable(GL_TEXTURE_2D);
    for (int i = 1; i < this->TextureResourceIds->GetNumberOfIds(); i++)
      {
      id = (GLuint) this->TextureResourceIds->GetId(i);
#ifdef GL_VERSION_1_1
      if (glIsTexture(id))
        {
        glDeleteTextures(1, &id);
        }
#else
      if (glIsList(id))
        {
        glDeleteLists(id,1);
        }
#endif
      }

    this->CleanUpRenderers();
    
    // Note: wglMakeCurrent(NULL,NULL) is valid according to the documentation
    // and works with nVidia and ATI but not with Intel. Passing an existing
    // device context works in any case.
    // see VTK Bug 7119.
    if(wglMakeCurrent(this->DeviceContext,NULL)!=TRUE) 
      {
      vtkErrorMacro("wglMakeCurrent failed in Clean(), error: " << GetLastError());
      }
    if (wglDeleteContext(this->ContextId) != TRUE) 
      {
      vtkErrorMacro("wglDeleteContext failed in Clean(), error: " << GetLastError());
      }
    this->ContextId = NULL;
    }
  if (this->Palette)
    {
    SelectPalette(this->DeviceContext, this->OldPalette, FALSE); // SVA delete the old palette
    DeleteObject(this->Palette);
    this->Palette = NULL;
    }
}

void vtkWin32OpenGLRenderWindow::CleanUpRenderers()
{
  // tell each of the renderers that this render window/graphics context
  // is being removed (the RendererCollection is removed by vtkRenderWindow's
  // destructor)
  vtkRenderer *ren;
  vtkCollectionSimpleIterator rsit;
  for (this->Renderers->InitTraversal(rsit); 
       (ren = this->Renderers->GetNextRenderer(rsit));)
    {
    ren->SetRenderWindow(NULL);
    ren->SetRenderWindow(this);
    }
}

LRESULT APIENTRY vtkWin32OpenGLRenderWindow::WndProc(HWND hWnd, UINT message, 
                                                     WPARAM wParam, 
                                                     LPARAM lParam)
{
  LRESULT res;

  vtkWin32OpenGLRenderWindow *me = 
    (vtkWin32OpenGLRenderWindow *)vtkGetWindowLong(hWnd,sizeof(vtkLONG));

  if (me && me->GetReferenceCount()>0)
    {
    me->Register(me);
    res = me->MessageProc(hWnd, message, wParam, lParam);
    me->UnRegister(me);
    }
  else
    {
    res = DefWindowProc(hWnd, message, wParam, lParam);
    }

  return res;
}

void vtkWin32OpenGLRenderWindow::SetWindowName( const char * _arg )
{
  vtkWindow::SetWindowName(_arg);
  if (this->WindowId)
    {
#ifdef UNICODE
    wchar_t *wname = new wchar_t [mbstowcs(NULL, this->WindowName, 32000)+1];
    mbstowcs(wname, this->WindowName, 32000);
    SetWindowText(this->WindowId, wname);
    delete [] wname;
#else
    SetWindowText(this->WindowId, this->WindowName);
#endif
    }
}

int vtkWin32OpenGLRenderWindow::GetEventPending()
{
  MSG msg;
  if (PeekMessage(&msg,this->WindowId,WM_MOUSEFIRST,WM_MOUSELAST,PM_NOREMOVE))
    {
    if (msg.message == WM_MOUSEMOVE)
      {
      PeekMessage(&msg,this->WindowId,WM_MOUSEFIRST,WM_MOUSELAST,PM_REMOVE);
      }
    if ((msg.message == WM_LBUTTONDOWN) ||
        (msg.message == WM_RBUTTONDOWN) ||
        (msg.message == WM_MBUTTONDOWN))
      {
      return 1;
      }
    }
  
  return 0;
}

// ----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::MakeCurrent()
{
  // Try to avoid doing anything (for performance).
  HGLRC current = wglGetCurrentContext();
  if (this->ContextId != current)
    {
    if(this->IsPicking && current)
      {
      vtkErrorMacro("Attempting to call MakeCurrent for a different window"
                    " than the one doing the picking, this can causes crashes"
                    " and/or bad pick results");
      }
    else 
      {
      if (wglMakeCurrent(this->DeviceContext, this->ContextId) != TRUE) 
        {
        LPVOID lpMsgBuf;
        ::FormatMessage( 
          FORMAT_MESSAGE_ALLOCATE_BUFFER | 
          FORMAT_MESSAGE_FROM_SYSTEM | 
          FORMAT_MESSAGE_IGNORE_INSERTS,
          NULL,
          GetLastError(),
          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
          (LPTSTR) &lpMsgBuf,
          0,
          NULL 
          );
        if(lpMsgBuf)
          {
#ifdef UNICODE
          wchar_t *wmsg = new wchar_t [mbstowcs(NULL, (const char*)lpMsgBuf, 32000)+1];
          wchar_t *wtemp = new wchar_t [mbstowcs(NULL, "wglMakeCurrent failed in MakeCurrent(), error: ", 32000)+1];
          mbstowcs(wmsg, (const char*)lpMsgBuf, 32000);
          mbstowcs(wtemp, "wglMakeCurrent failed in MakeCurrent(), error: ", 32000);
          vtkErrorMacro(<< wcscat(wtemp, wmsg));
          delete [] wmsg;
          delete [] wtemp;
#else
          vtkErrorMacro("wglMakeCurrent failed in MakeCurrent(), error: " 
                        << (LPCTSTR)lpMsgBuf);
#endif
          ::LocalFree( lpMsgBuf );
          }
        }
      }
    }
}

// ----------------------------------------------------------------------------
// Description:
// Tells if this window is the current OpenGL context for the calling thread.
bool vtkWin32OpenGLRenderWindow::IsCurrent()
{
  return this->ContextId!=0 && this->ContextId==wglGetCurrentContext();
}

// ----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::SetSize(int x, int y)
{
  static int resizing = 0;
  if ((this->Size[0] != x) || (this->Size[1] != y))
    {
    this->Modified();
    this->Size[0] = x;
    this->Size[1] = y;

    if (this->Interactor)
      {
      this->Interactor->SetSize(x, y);
      }

    if (this->OffScreenRendering)
      {
      if(!this->CreatingOffScreenWindow)
        {
        if (!resizing)
          {
          resizing = 1;
          this->CleanUpOffScreenRendering();
          this->CreateOffScreenWindow(x,y);
          resizing = 0;
          }
        }
      }
    
    else if (this->Mapped)
      {
      if (!resizing)
        {
        resizing = 1;
        
        if (this->ParentId)
          {
          SetWindowExtEx(this->DeviceContext,x,y,NULL);
          SetViewportExtEx(this->DeviceContext,x,y,NULL);
          SetWindowPos(this->WindowId,HWND_TOP,0,0,
                       x, y, SWP_NOMOVE | SWP_NOZORDER);
          }
        else
          {
          SetWindowPos(this->WindowId,HWND_TOP,0,0,
                       x+2*GetSystemMetrics(SM_CXFRAME),
                       y+2*GetSystemMetrics(SM_CYFRAME) +GetSystemMetrics(SM_CYCAPTION),
                       SWP_NOMOVE | SWP_NOZORDER);
          }
        resizing = 0;
        }
      }
    }
}

void vtkWin32OpenGLRenderWindow::SetPosition(int x, int y)
{
  static int resizing = 0;

  if ((this->Position[0] != x) || (this->Position[1] != y))
    {
    this->Modified();
    this->Position[0] = x;
    this->Position[1] = y;
    if (this->Mapped)
      {
      if (!resizing)
        {
        resizing = 1;
        
        SetWindowPos(this->WindowId,HWND_TOP,x,y,
                     0, 0, SWP_NOSIZE | SWP_NOZORDER);
        resizing = 0;
        }
      }
    }
}


// End the rendering process and display the image.
void vtkWin32OpenGLRenderWindow::Frame(void)
{
  this->MakeCurrent();
  if (!this->AbortRender && this->DoubleBuffer && this->SwapBuffers)
    {
    // If this check is not enforced, we crash in offscreen rendering
    if (this->DeviceContext)
      {
      // use global scope to get Win32 API SwapBuffers and not be
      // confused with this->SwapBuffers
      ::SwapBuffers(this->DeviceContext);
      vtkDebugMacro(<< " SwapBuffers\n");
      }
    }
  else
    {
    glFlush();
    }
}

int vtkWin32OpenGLRenderWindow::SupportsOpenGL()
{
  MakeCurrent();
  if (!this->DeviceContext)
    {
    return 0;
    }

  int pixelFormat = GetPixelFormat(this->DeviceContext);
  PIXELFORMATDESCRIPTOR pfd;

  DescribePixelFormat(this->DeviceContext, pixelFormat,
                      sizeof(PIXELFORMATDESCRIPTOR), &pfd);

  return (pfd.dwFlags & PFD_SUPPORT_OPENGL) ? 1:0;

}


int vtkWin32OpenGLRenderWindow::IsDirect()
{

  MakeCurrent();
  if (!this->DeviceContext)
    {
    return 0;
    }

  int pixelFormat = GetPixelFormat(this->DeviceContext);
  PIXELFORMATDESCRIPTOR pfd;

  DescribePixelFormat(this->DeviceContext, pixelFormat,
                      sizeof(PIXELFORMATDESCRIPTOR), &pfd);

  return (pfd.dwFlags & PFD_GENERIC_FORMAT) ? 0:1;

}


const char* vtkWin32OpenGLRenderWindow::ReportCapabilities()
{
  MakeCurrent();

  if (!this->DeviceContext)
    {
    return "no device context";
    }

  int pixelFormat = GetPixelFormat(this->DeviceContext);
  PIXELFORMATDESCRIPTOR pfd;

  DescribePixelFormat(this->DeviceContext, pixelFormat,
                      sizeof(PIXELFORMATDESCRIPTOR), &pfd);

  const char *glVendor = (const char *) glGetString(GL_VENDOR);
  const char *glRenderer = (const char *) glGetString(GL_RENDERER);
  const char *glVersion = (const char *) glGetString(GL_VERSION);
  const char *glExtensions = (const char *) glGetString(GL_EXTENSIONS);

  vtksys_ios::ostringstream strm;
  strm << "OpenGL vendor string:  " << glVendor << endl;
  strm << "OpenGL renderer string:  " << glRenderer << endl;
  strm << "OpenGL version string:  " << glVersion << endl;
  strm << "OpenGL extensions:  " << glExtensions << endl;
  strm << "PixelFormat Descriptor:" << endl;
  strm << "depth:  " << static_cast<int>(pfd.cDepthBits) << endl;
  if (pfd.cColorBits <= 8)
    {
    strm << "class:  PseudoColor" << endl;
    } 
  else
    {
    strm << "class:  TrueColor" << endl;
    }
  strm << "buffer size:  " << static_cast<int>(pfd.cColorBits) << endl;
  strm << "level:  " << static_cast<int>(pfd.bReserved) << endl;
  if (pfd.iPixelType == PFD_TYPE_RGBA)
    {
    strm << "renderType:  rgba" << endl;
    }
  else
    {
    strm <<"renderType:  ci" << endl;
    }
  if (pfd.dwFlags & PFD_DOUBLEBUFFER) {
  strm << "double buffer:  True" << endl;
  } else {
  strm << "double buffer:  False" << endl;
  }
  if (pfd.dwFlags & PFD_STEREO) {
  strm << "stereo:  True" << endl;  
  } else {
  strm << "stereo:  False" << endl;
  }
  if (pfd.dwFlags & PFD_GENERIC_FORMAT) {
  strm << "hardware acceleration:  False" << endl; 
  } else {
  strm << "hardware acceleration:  True" << endl; 
  }
  strm << "rgba:  redSize=" << static_cast<int>(pfd.cRedBits) << " greenSize=" << static_cast<int>(pfd.cGreenBits) << "blueSize=" << static_cast<int>(pfd.cBlueBits) << "alphaSize=" << static_cast<int>(pfd.cAlphaBits) << endl;
  strm << "aux buffers:  " << static_cast<int>(pfd.cAuxBuffers)<< endl;
  strm << "depth size:  " << static_cast<int>(pfd.cDepthBits) << endl;
  strm << "stencil size:  " << static_cast<int>(pfd.cStencilBits) << endl;
  strm << "accum:  redSize=" << static_cast<int>(pfd.cAccumRedBits) << " greenSize=" << static_cast<int>(pfd.cAccumGreenBits) << "blueSize=" << static_cast<int>(pfd.cAccumBlueBits) << "alphaSize=" << static_cast<int>(pfd.cAccumAlphaBits) << endl;

  delete[] this->Capabilities;
  
  size_t len = strm.str().length() + 1;
  this->Capabilities = new char[len];
  strncpy(this->Capabilities, strm.str().c_str(), len);
  
  return this->Capabilities;
}

 
void vtkWin32OpenGLRenderWindow::SetupPixelFormat(HDC hDC, DWORD dwFlags, 
                                                  int debug, int bpp, 
                                                  int zbpp)
{
  PIXELFORMATDESCRIPTOR pfd = {
    sizeof(PIXELFORMATDESCRIPTOR),  /* size */
    1,                              /* version */
    dwFlags         ,               /* support double-buffering */
    PFD_TYPE_RGBA,                  /* color type */
    bpp,                             /* prefered color depth */
    0, 0, 0, 0, 0, 0,               /* color bits (ignored) */
    this->AlphaBitPlanes ? bpp/4 : 0, /* no alpha buffer */
    0,                              /* alpha bits (ignored) */
    0,                              /* no accumulation buffer */
    0, 0, 0, 0,                     /* accum bits (ignored) */
    zbpp,                           /* depth buffer */
    this->StencilCapable,           /* stencil buffer */
    0,                              /* no auxiliary buffers */
    PFD_MAIN_PLANE,                 /* main layer */
    0,                              /* reserved */
    0, 0, 0,                        /* no layer, visible, damage masks */
  };
  int pixelFormat;
  // Only try to set pixel format if we do not currently have one
  int currentPixelFormat = GetPixelFormat(hDC);
  // if there is a current pixel format, then make sure it
  // supports OpenGL
  if (currentPixelFormat != 0)
    {
    DescribePixelFormat(hDC, currentPixelFormat,sizeof(pfd), &pfd);
    if (!(pfd.dwFlags & PFD_SUPPORT_OPENGL))
      {
#ifdef UNICODE
      MessageBox(WindowFromDC(hDC), 
                 L"Invalid pixel format, no OpenGL support",
                 L"Error",
                 MB_ICONERROR | MB_OK);
#else
      MessageBox(WindowFromDC(hDC), 
                 "Invalid pixel format, no OpenGL support",
                 "Error",
                 MB_ICONERROR | MB_OK);
#endif
      if (this->HasObserver(vtkCommand::ExitEvent))
        {
        this->InvokeEvent(vtkCommand::ExitEvent, NULL);
        return;
        }
      else
        {
        exit(1);
        }
      }         
    }
  else
    {
    // hDC has no current PixelFormat, so 
    pixelFormat = ChoosePixelFormat(hDC, &pfd);
    if (pixelFormat == 0)
      {
#ifdef UNICODE
      MessageBox(WindowFromDC(hDC), L"ChoosePixelFormat failed.", L"Error",
                 MB_ICONERROR | MB_OK);
#else
      MessageBox(WindowFromDC(hDC), "ChoosePixelFormat failed.", "Error",
                 MB_ICONERROR | MB_OK);
#endif
      if (this->HasObserver(vtkCommand::ExitEvent))
        {
        this->InvokeEvent(vtkCommand::ExitEvent, NULL);
        return;
        }
      else
        {
        exit(1);
        }
      }
    DescribePixelFormat(hDC, pixelFormat,sizeof(pfd), &pfd); 
    if (SetPixelFormat(hDC, pixelFormat, &pfd) != TRUE) 
      {
      // int err = GetLastError();
#ifdef UNICODE
      MessageBox(WindowFromDC(hDC), L"SetPixelFormat failed.", L"Error",
                 MB_ICONERROR | MB_OK);
#else
      MessageBox(WindowFromDC(hDC), "SetPixelFormat failed.", "Error",
                 MB_ICONERROR | MB_OK);
#endif
      if (this->HasObserver(vtkCommand::ExitEvent))
        {
        this->InvokeEvent(vtkCommand::ExitEvent, NULL);
        return;
        }
      else
        {
        exit(1);
        }
      }
    }
  if (debug && (dwFlags & PFD_STEREO) && !(pfd.dwFlags & PFD_STEREO))
    {
    vtkGenericWarningMacro("No Stereo Available!");
    this->StereoCapableWindow = 0;
    }
}

void vtkWin32OpenGLRenderWindow::SetupPalette(HDC hDC)
{
  int pixelFormat = GetPixelFormat(hDC);
  PIXELFORMATDESCRIPTOR pfd;
  LOGPALETTE* pPal;
  int paletteSize;

  DescribePixelFormat(hDC, pixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);

  if (pfd.dwFlags & PFD_NEED_PALETTE) {
  paletteSize = 1 << pfd.cColorBits;
  } else {
  return;
  }

  pPal = (LOGPALETTE*)
    malloc(sizeof(LOGPALETTE) + paletteSize * sizeof(PALETTEENTRY));
  pPal->palVersion = 0x300;
  pPal->palNumEntries = paletteSize;

  /* build a simple RGB color palette */
  {
  int redMask = (1 << pfd.cRedBits) - 1;
  int greenMask = (1 << pfd.cGreenBits) - 1;
  int blueMask = (1 << pfd.cBlueBits) - 1;
  int i;

  for (i=0; i<paletteSize; ++i) {
  pPal->palPalEntry[i].peRed =
    (((i >> pfd.cRedShift) & redMask) * 255) / redMask;
  pPal->palPalEntry[i].peGreen =
    (((i >> pfd.cGreenShift) & greenMask) * 255) / greenMask;
  pPal->palPalEntry[i].peBlue =
    (((i >> pfd.cBlueShift) & blueMask) * 255) / blueMask;
  pPal->palPalEntry[i].peFlags = 0;
  }
  }

  this->Palette = CreatePalette(pPal);
  free(pPal);

  if (this->Palette) {
  this->OldPalette = SelectPalette(hDC, this->Palette, FALSE);
  RealizePalette(hDC);
  }
}


LRESULT vtkWin32OpenGLRenderWindow::MessageProc(HWND hWnd, UINT message, 
                                                WPARAM wParam, LPARAM lParam)
{
  switch (message) 
    {
    case WM_CREATE:
    {
    // nothing to be done here, opengl is initilized after the call to
    // create now
    return 0;
    }
    case WM_DESTROY:
      this->Clean();
      if (this->DeviceContext)
        {
        ReleaseDC(this->WindowId, this->DeviceContext);
        this->DeviceContext = NULL;
        this->WindowId = NULL;
        }
      return 0;
    case WM_SIZE:
      /* track window size changes */
      if (this->ContextId) 
        {
        this->SetSize((int) LOWORD(lParam),(int) HIWORD(lParam));
        return 0;
        }
    case WM_PALETTECHANGED:
      /* realize palette if this is *not* the current window */
      if (this->ContextId && this->Palette && (HWND) wParam != hWnd) 
        {
        SelectPalette(this->DeviceContext, this->OldPalette, FALSE);
        UnrealizeObject(this->Palette);
        this->OldPalette = SelectPalette(this->DeviceContext, 
                                         this->Palette, FALSE);
        RealizePalette(this->DeviceContext);
        this->Render();
        }
      break;
    case WM_QUERYNEWPALETTE:
      /* realize palette if this is the current window */
      if (this->ContextId && this->Palette) 
        {
        SelectPalette(this->DeviceContext, this->OldPalette, FALSE);
        UnrealizeObject(this->Palette);
        this->OldPalette = SelectPalette(this->DeviceContext, 
                                         this->Palette, FALSE);
        RealizePalette(this->DeviceContext);
        this->Render();
        return TRUE;
        }
      break;
    case WM_PAINT:
    {
    PAINTSTRUCT ps;
    BeginPaint(hWnd, &ps);
    if (this->ContextId) 
      {
      this->Render();
      }
    EndPaint(hWnd, &ps);
    return 0;
    }
    break;
    case WM_ERASEBKGND:
      return TRUE;
    case WM_SETCURSOR:
      if (HTCLIENT == LOWORD(lParam))
        {
        this->SetCurrentCursor(this->GetCurrentCursor());
        return TRUE;
        }
      break;
    default:
      this->InvokeEvent(vtkCommand::RenderWindowMessageEvent, &message);
      break;
    }
  return DefWindowProc(hWnd, message, wParam, lParam);
}


void vtkWin32OpenGLRenderWindow::InitializeApplication()
{
  // get the applicaiton instance if we don't have one already
  if (!this->ApplicationInstance)
    {
    // if we have a parent window get the app instance from it
    if (this->ParentId)
      {
      this->ApplicationInstance = (HINSTANCE)vtkGetWindowLong(this->ParentId,vtkGWL_HINSTANCE);
      }
    else
      {
      this->ApplicationInstance = GetModuleHandle(NULL); /*AfxGetInstanceHandle();*/
      }
    }
}

void vtkWin32OpenGLRenderWindow::CreateAWindow()
{
  if(this->WindowIdReferenceCount == 0)
    {
    static int count = 1;
    char *windowName;
    
    if (!this->WindowId)
      {
      WNDCLASS wndClass;
      this->DeviceContext = 0;
      
      int len = static_cast<int>(strlen("Visualization Toolkit - Win32OpenGL #")) 
        + (int)ceil( (double) log10( (double)(count+1) ) )
        + 1; 
      windowName = new char [ len ];
      sprintf(windowName,"Visualization Toolkit - Win32OpenGL #%i",count++);
      this->SetWindowName(windowName);
      delete [] windowName;
      
      // has the class been registered ?
#ifdef UNICODE
      if (!GetClassInfo(this->ApplicationInstance,L"vtkOpenGL",&wndClass))
#else
        if (!GetClassInfo(this->ApplicationInstance,"vtkOpenGL",&wndClass))
#endif
          {
          wndClass.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
          wndClass.lpfnWndProc = vtkWin32OpenGLRenderWindow::WndProc;
          wndClass.cbClsExtra = 0;
          wndClass.hInstance = this->ApplicationInstance;
          wndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
          wndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
          wndClass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
          wndClass.lpszMenuName = NULL;
#ifdef UNICODE
          wndClass.lpszClassName = L"vtkOpenGL";
#else
          wndClass.lpszClassName = "vtkOpenGL";
#endif
          // vtk doesn't use the first extra vtkLONG's worth of bytes,
          // but app writers may want them, so we provide them. VTK
          // does use the second vtkLONG's worth of bytes of extra space.
          wndClass.cbWndExtra = 2 * sizeof(vtkLONG);
          RegisterClass(&wndClass);
          }
      
#ifdef UNICODE
      wchar_t *wname = new wchar_t [mbstowcs(NULL, this->WindowName, 32000)+1];
      mbstowcs(wname, this->WindowName, 32000);
#endif
      int x = ((this->Position[0] >= 0) ? this->Position[0] : 5);
      int y = ((this->Position[1] >= 0) ? this->Position[1] : 5);
      int height = ((this->Size[1] > 0) ? this->Size[1] : 300);
      int width = ((this->Size[0] > 0) ? this->Size[0] : 300);
      
      /* create window */
      if (this->ParentId)
        {
#ifdef UNICODE
        this->WindowId = CreateWindow(
          L"vtkOpenGL", wname,
          WS_CHILD | WS_CLIPCHILDREN /*| WS_CLIPSIBLINGS*/,
          x, y, width, height,
          this->ParentId, NULL, this->ApplicationInstance, NULL);
#else
        this->WindowId = CreateWindow(
          "vtkOpenGL", this->WindowName,
          WS_CHILD | WS_CLIPCHILDREN /*| WS_CLIPSIBLINGS*/,
          x, y, width, height,
          this->ParentId, NULL, this->ApplicationInstance, NULL);
#endif
        }
      else
        {
        DWORD style;
        if (this->Borders)
          {
          style = WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN /*| WS_CLIPSIBLINGS*/;
          }
        else
          {
          style = WS_POPUP | WS_CLIPCHILDREN /*| WS_CLIPSIBLINGS*/;
          }
#ifdef UNICODE
        this->WindowId = CreateWindow(
          L"vtkOpenGL", wname, style,
          x,y, width+2*GetSystemMetrics(SM_CXFRAME),
          height+2*GetSystemMetrics(SM_CYFRAME) 
          +GetSystemMetrics(SM_CYCAPTION),
          NULL, NULL, this->ApplicationInstance, NULL);
#else
        this->WindowId = CreateWindow(
          "vtkOpenGL", this->WindowName, style,
          x,y, width+2*GetSystemMetrics(SM_CXFRAME),
          height+2*GetSystemMetrics(SM_CYFRAME)
          +GetSystemMetrics(SM_CYCAPTION),
          NULL, NULL, this->ApplicationInstance, NULL);
#endif
        }
#ifdef UNICODE
      delete [] wname;
#endif
      
      if (!this->WindowId)
        {
        vtkErrorMacro("Could not create window, error:  " << GetLastError());
        return;
        }
      // extract the create info
      
      /* display window */
      if(!this->OffScreenRendering)
        {
        ShowWindow(this->WindowId, SW_SHOW);
        }
      //UpdateWindow(this->WindowId);
      this->OwnWindow = 1;
      vtkSetWindowLong(this->WindowId,sizeof(vtkLONG),(vtkLONG)this);
      }
    if (!this->DeviceContext)
      {
      this->DeviceContext = GetDC(this->WindowId);
      }
    if (this->StereoCapableWindow)
      {
      this->SetupPixelFormat(this->DeviceContext, PFD_SUPPORT_OPENGL |
                             PFD_DRAW_TO_WINDOW | PFD_DOUBLEBUFFER |
                             PFD_STEREO, this->GetDebug(), 32, 32);
      }
    else
      {
      this->SetupPixelFormat(this->DeviceContext, PFD_SUPPORT_OPENGL |
                             PFD_DRAW_TO_WINDOW | PFD_DOUBLEBUFFER,
                             this->GetDebug(), 32, 32);
      }
    this->SetupPalette(this->DeviceContext);
    this->ContextId = wglCreateContext(this->DeviceContext);
    if (this->ContextId == NULL) 
      {
      vtkErrorMacro("wglCreateContext failed in CreateAWindow(), error: " << GetLastError());
      }
    this->MakeCurrent();
    
    // wipe out any existing display lists
    vtkRenderer* ren;
    vtkCollectionSimpleIterator rsit;
    for (this->Renderers->InitTraversal(rsit); 
         (ren = this->Renderers->GetNextRenderer(rsit));)
      {
      ren->SetRenderWindow(0);
      ren->SetRenderWindow(this);
      }
    this->OpenGLInit();
    this->Mapped = 1;
    this->WindowIdReferenceCount = 1;
    }
  else
    {
    ++this->WindowIdReferenceCount;
    }
}

// Initialize the window for rendering.
void vtkWin32OpenGLRenderWindow::WindowInitialize()
{ 
  // create our own window if not already set
  this->OwnWindow = 0;
  if (!this->MFChandledWindow)
    {
    this->InitializeApplication();
    this->CreateAWindow();
    }   
  else 
    {
    this->MakeCurrent(); // hsr
    this->OpenGLInit();
    }
  
  // set the DPI
  this->SetDPI(GetDeviceCaps(this->DeviceContext, LOGPIXELSY));
}

// Initialize the rendering window.
void vtkWin32OpenGLRenderWindow::Initialize (void)
{
  // make sure we havent already been initialized 
  if (!this->OffScreenRendering && !this->ContextId)
    {
    this->WindowInitialize();
    }
  else
    {
    if(this->OffScreenRendering && !(this->ContextId ||
                                     this->OffScreenUseFrameBuffer))
      {
      this->InitializeApplication();
      int width = ((this->Size[0] > 0) ? this->Size[0] : 300);
      int height = ((this->Size[1] > 0) ? this->Size[1] : 300);
      this->CreateOffScreenWindow(width,height);
      }
    }
}

void vtkWin32OpenGLRenderWindow::Finalize (void)
{
  if (this->CursorHidden)
    {
    this->ShowCursor();
    }

  if (this->OffScreenRendering)
    {
    this->CleanUpOffScreenRendering();
    }
  this->DestroyWindow();
}

void vtkWin32OpenGLRenderWindow::DestroyWindow()
{
  if(this->WindowIdReferenceCount > 0)
    {
    --this->WindowIdReferenceCount;
    if(this->WindowIdReferenceCount == 0)
      {
      this->Clean();
      if (this->WindowId)
        {
        ReleaseDC(this->WindowId, this->DeviceContext);
        // can't set WindowId=NULL, needed for DestroyWindow
        this->DeviceContext = NULL;
        
        // clear the extra data before calling destroy
        vtkSetWindowLong(this->WindowId,sizeof(vtkLONG),(vtkLONG)0);
        if(this->OwnWindow)
          {
          ::DestroyWindow(this->WindowId);
          this->WindowId=0;
          }
        }
      }
    }
}

// Get the current size of the window.
int *vtkWin32OpenGLRenderWindow::GetSize(void)
{
  // if we aren't mapped then just return the ivar 
  if (this->Mapped)
    {
    RECT rect;

    //  Find the current window size 
    if (GetClientRect(this->WindowId, &rect))
      {    
      this->Size[0] = rect.right;
      this->Size[1] = rect.bottom;
      }
    else 
      {
      this->Size[0] = 0;
      this->Size[1] = 0;
      }

    }

  return this->vtkOpenGLRenderWindow::GetSize();
}

// Get the current size of the window.
int *vtkWin32OpenGLRenderWindow::GetScreenSize(void)
{
  RECT rect;

  SystemParametersInfo(SPI_GETWORKAREA, 0, &rect, 0);
                            
  this->Size[0] = rect.right - rect.left;
  this->Size[1] = rect.bottom - rect.top;
  
  return this->Size;
}

// Get the position in screen coordinates of the window.
int *vtkWin32OpenGLRenderWindow::GetPosition(void)
{
  // if we aren't mapped then just return the ivar 
  if (!this->Mapped)
    {
    return this->Position;
    }

  //  Find the current window position 
  //  x,y,&this->Position[0],&this->Position[1],&child);

  return this->Position;
}

// Change the window to fill the entire screen.
void vtkWin32OpenGLRenderWindow::SetFullScreen(int arg)
{
  int *temp;
  
  if (this->FullScreen == arg)
    {
    return;
    }
  
  if (!this->Mapped)
    {
    this->PrefFullScreen();
    return;
    }

  // set the mode 
  this->FullScreen = arg;
  if (this->FullScreen <= 0)
    {
    this->Position[0] = this->OldScreen[0];
    this->Position[1] = this->OldScreen[1];
    this->Size[0] = this->OldScreen[2]; 
    this->Size[1] = this->OldScreen[3];
    this->Borders = this->OldScreen[4];
    }
  else
    {
    // if window already up get its values 
    if (this->WindowId)
      {
      temp = this->GetPosition();      
      this->OldScreen[0] = temp[0];
      this->OldScreen[1] = temp[1];

      this->OldScreen[4] = this->Borders;
      this->PrefFullScreen();
      }
    }
  
  // remap the window 
  this->WindowRemap();

  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 vtkWin32OpenGLRenderWindow::SetStereoCapableWindow(int capable)
{
  if (this->ContextId == 0)
    {
    vtkRenderWindow::SetStereoCapableWindow(capable);
    }
  else
    {
    vtkWarningMacro(<< "Requesting a StereoCapableWindow must be performed "
                    << "before the window is realized, i.e. before a render.");
    }
}


// Set the preferred window size to full screen.
void vtkWin32OpenGLRenderWindow::PrefFullScreen()
{
  int *size;

  size = this->GetScreenSize();

  // use full screen 
  this->Position[0] = 0;
  this->Position[1] = 0;
  this->Size[0] = size[0] - 2*GetSystemMetrics(SM_CXFRAME);
  this->Size[1] = size[1] - 
    2*GetSystemMetrics(SM_CYFRAME) - GetSystemMetrics(SM_CYCAPTION);

  // don't show borders 
  this->Borders = 0;
}

// Remap the window.
void vtkWin32OpenGLRenderWindow::WindowRemap()
{
  // close everything down
  this->Finalize();
  
  // set the default windowid 
  this->WindowId = this->NextWindowId;
  this->NextWindowId = 0;

  // and set it up!
  this->Initialize();
}

void vtkWin32OpenGLRenderWindow::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "ContextId: " << this->ContextId << "\n";
  os << indent << "Next Window Id: " << this->NextWindowId << "\n";
  os << indent << "Window Id: " << this->WindowId << "\n";
}

// Get the window id.
HWND vtkWin32OpenGLRenderWindow::GetWindowId()
{
  vtkDebugMacro(<< "Returning WindowId of " << this->WindowId << "\n"); 

  return this->WindowId;
}

// Set the window id to a pre-existing window.
void vtkWin32OpenGLRenderWindow::SetWindowId(HWND arg)
{
  vtkDebugMacro(<< "Setting WindowId to " << arg << "\n");
  
  if (arg != this->WindowId)
    {
    this->WindowId = arg;
    if (this->ContextId) 
      {
      wglDeleteContext(this->ContextId);
      }
    this->ContextId = 0;
    this->DeviceContext = 0;
    }
}

// Set this RenderWindow's X window id to a pre-existing window.
void vtkWin32OpenGLRenderWindow::SetWindowInfo(char *info)
{
  int tmp;
  
  sscanf(info,"%i",&tmp);

  this->WindowId = (HWND)tmp;
  vtkDebugMacro(<< "Setting WindowId to " << this->WindowId << "\n"); 
}

void vtkWin32OpenGLRenderWindow::SetNextWindowInfo(char *info)
{
  int tmp;
  
  sscanf(info,"%i",&tmp);

  this->SetNextWindowId((HWND)tmp);
}

void vtkWin32OpenGLRenderWindow::SetDisplayId(void * arg)
{ 
  this->DeviceContext = (HDC) arg;
}

void vtkWin32OpenGLRenderWindow::SetContextId(HGLRC arg)
{
  this->ContextId = arg;
}

void vtkWin32OpenGLRenderWindow::SetDeviceContext(HDC arg) 
{
  this->DeviceContext = arg;
  this->MFChandledWindow = TRUE;
}

// Sets the HWND id of the window that WILL BE created.
void vtkWin32OpenGLRenderWindow::SetParentInfo(char *info)
{
  int tmp;
  
  sscanf(info,"%i",&tmp);

  this->ParentId = (HWND)tmp;
  vtkDebugMacro(<< "Setting ParentId to " << this->ParentId << "\n"); 
}

// Set the window id to a pre-existing window.
void vtkWin32OpenGLRenderWindow::SetParentId(HWND arg)
{
  vtkDebugMacro(<< "Setting ParentId to " << arg << "\n"); 

  this->ParentId = arg;
}

// Set the window id of the new window once a WindowRemap is done.
void vtkWin32OpenGLRenderWindow::SetNextWindowId(HWND arg)
{
  vtkDebugMacro(<< "Setting NextWindowId to " << arg << "\n"); 

  this->NextWindowId = arg;
}

void vtkWin32OpenGLRenderWindow::SetNextWindowId(void *arg)
{
  this->SetNextWindowId((HWND)arg);
}

// Begin the rendering process.
void vtkWin32OpenGLRenderWindow::Start(void)
{
  // if the renderer has not been initialized, do so now
  if (!this->ContextId)
    {
    this->Initialize();
    }

  // set the current window 
  this->MakeCurrent();
}


void vtkWin32OpenGLRenderWindow::SetOffScreenRendering(int offscreen)
{
  if (offscreen == this->OffScreenRendering)
    {
    return;
    }

  this->vtkRenderWindow::SetOffScreenRendering(offscreen);

  if (offscreen)
    {
    int size[2];
    size[0] = (this->Size[0] > 0) ? this->Size[0] : 300;
    size[1] = (this->Size[1] > 0) ? this->Size[1] : 300;
    this->SaveScreenRendering();
    this->CreateOffScreenWindow(size[0],size[1]);
    }
  else
    {
    this->CleanUpOffScreenRendering();
    if (!this->WindowId)
      {
      this->WindowInitialize();
      this->OpenGLInit();
      if (this->Interactor)
        {
        this->Interactor->ReInitialize();
        }
      this->DoubleBuffer = 1;
      }
    else
      {
      this->ResumeScreenRendering();
      }
    }
}

void vtkWin32OpenGLRenderWindow::SaveScreenRendering()
{
  this->ScreenMapped = this->Mapped;
  this->ScreenWindowSize[0] = this->Size[0];
  this->ScreenWindowSize[1] = this->Size[1];
  this->ScreenDeviceContext = this->DeviceContext;
  this->ScreenDoubleBuffer = this->DoubleBuffer;
  this->ScreenContextId = this->ContextId;
}

void vtkWin32OpenGLRenderWindow::CreateOffScreenWindow(int width,
                                                       int height)
{
  int status = this->CreatingOffScreenWindow;
  this->CreatingOffScreenWindow = 1;
  if(!this->CreateHardwareOffScreenWindow(width,height))
    {
#ifdef UNICODE
    HDC dc = CreateDC(L"DISPLAY", 0, 0, 0);
#else
    HDC dc = CreateDC("DISPLAY", 0, 0, 0);
#endif
    this->CreateOffScreenDC(width,height,dc);
    DeleteDC(dc);
    }
  this->CreatingOffScreenWindow = status;
} 

void vtkWin32OpenGLRenderWindow::CreateOffScreenDC(int xsize, int ysize,
                                                   HDC aHdc)
{
  int dataWidth = ((xsize*3+3)/4)*4;
  
  this->MemoryDataHeader.bmiHeader.biSize = 40;
  this->MemoryDataHeader.bmiHeader.biWidth = xsize;
  this->MemoryDataHeader.bmiHeader.biHeight = ysize;
  this->MemoryDataHeader.bmiHeader.biPlanes = 1;
  this->MemoryDataHeader.bmiHeader.biBitCount = 24;
  this->MemoryDataHeader.bmiHeader.biCompression = BI_RGB;
  this->MemoryDataHeader.bmiHeader.biClrUsed = 0;
  this->MemoryDataHeader.bmiHeader.biClrImportant = 0;
  this->MemoryDataHeader.bmiHeader.biSizeImage = dataWidth*ysize;
  this->MemoryDataHeader.bmiHeader.biXPelsPerMeter = 10000;
  this->MemoryDataHeader.bmiHeader.biYPelsPerMeter = 10000;
  
  HBITMAP dib = CreateDIBSection(aHdc,
                                 &this->MemoryDataHeader, DIB_RGB_COLORS,
                                 (void **)(&(this->MemoryData)),  NULL, 0);
  SIZE oldSize;
  SetBitmapDimensionEx(dib, xsize, ysize, &oldSize);
  // try using a DIBsection
  this->CreateOffScreenDC(dib, aHdc);
}

void vtkWin32OpenGLRenderWindow::CreateOffScreenDC(HBITMAP hbmp, HDC aHdc)
{
  BITMAP bm;
  GetObject(hbmp, sizeof(BITMAP), &bm);

  this->MemoryBuffer = hbmp;
  
  // Create a compatible device context
  this->MemoryHdc = (HDC)CreateCompatibleDC(aHdc);
  
  // Put the bitmap into the device context
  SelectObject(this->MemoryHdc, this->MemoryBuffer);
  
  // Renderers will need to redraw anything cached in display lists
  this->CleanUpRenderers();

  // adjust settings for renderwindow
  this->Mapped =0;
  this->Size[0] = bm.bmWidth;
  this->Size[1] = bm.bmHeight;
  
  this->DeviceContext = this->MemoryHdc;
  this->DoubleBuffer = 0;
  this->SetupPixelFormat(this->DeviceContext, 
                         PFD_SUPPORT_OPENGL | PFD_SUPPORT_GDI | 
                         PFD_DRAW_TO_BITMAP, this->GetDebug(), 24, 32);
  this->SetupPalette(this->DeviceContext);
  this->ContextId = wglCreateContext(this->DeviceContext);
  if (this->ContextId == NULL) 
    {
    vtkErrorMacro("wglCreateContext failed in CreateOffScreenDC(), error: " << GetLastError());
    }
  this->MakeCurrent();
  this->OpenGLInit();
}

void vtkWin32OpenGLRenderWindow::SetupMemoryRendering(int xsize, int ysize,
                                                      HDC aHdc)
{
  // save the current state
  this->ScreenMapped = this->Mapped;
  this->ScreenWindowSize[0] = this->Size[0];
  this->ScreenWindowSize[1] = this->Size[1];
  this->ScreenDeviceContext = this->DeviceContext;
  this->ScreenDoubleBuffer = this->DoubleBuffer;
  this->ScreenContextId = this->ContextId;

  this->CreateOffScreenDC(xsize, ysize, aHdc);
}

void vtkWin32OpenGLRenderWindow::SetupMemoryRendering(HBITMAP hbmp)
{
#ifdef UNICODE
  HDC dc = CreateDC(L"DISPLAY", 0, 0, 0);
#else
  HDC dc = CreateDC("DISPLAY", 0, 0, 0);
#endif

  // save the current state
  this->ScreenMapped = this->Mapped;
  this->ScreenWindowSize[0] = this->Size[0];
  this->ScreenWindowSize[1] = this->Size[1];
  this->ScreenDeviceContext = this->DeviceContext;
  this->ScreenDoubleBuffer = this->DoubleBuffer;
  this->ScreenContextId = this->ContextId;

  this->CreateOffScreenDC(hbmp, dc);
  DeleteDC(dc); 
}

HDC vtkWin32OpenGLRenderWindow::GetMemoryDC()
{
  return this->MemoryHdc;
}

void vtkWin32OpenGLRenderWindow::CleanUpOffScreenRendering(void)
{
  if(this->OffScreenUseFrameBuffer)
    {
    this->DestroyHardwareOffScreenWindow();
    }
  else
    {
    if (!this->MemoryHdc)
      {
      return;
      }
      
    GdiFlush();
      
    // we need to release resources
    this->CleanUpRenderers();
    DeleteDC(this->MemoryHdc);
    this->MemoryHdc = (HDC)0;
    DeleteObject(this->MemoryBuffer);
    if (wglDeleteContext(this->ContextId) != TRUE) 
      {
      vtkErrorMacro("wglDeleteContext failed in CleanUpOffScreenRendering(), error: " << GetLastError());
      }
    this->ContextId=0;
    }
}

void vtkWin32OpenGLRenderWindow::ResumeScreenRendering(void)
{
  // release OpenGL graphics resources before switch back to on-screen. 
  if(this->ContextId!=0)
    {
      this->MakeCurrent();
      this->CleanUpRenderers();
    }

  this->Mapped = this->ScreenMapped;
  this->Size[0] = this->ScreenWindowSize[0];
  this->Size[1] = this->ScreenWindowSize[1];
  this->DeviceContext = this->ScreenDeviceContext;
  this->DoubleBuffer = this->ScreenDoubleBuffer;
  this->ContextId = this->ScreenContextId;
  this->MakeCurrent();
}

//----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::HideCursor()
{
  if (this->CursorHidden)
    {
    return;
    }
  this->CursorHidden = 1;

  ::ShowCursor(!this->CursorHidden);
}

//----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::ShowCursor()
{
  if (!this->CursorHidden)
    {
    return;
    }
  this->CursorHidden = 0;

  ::ShowCursor(!this->CursorHidden);
}                                  

//----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::SetCursorPosition(int x, int y) 
{
  int *size = this->GetSize();

  POINT point;
  point.x = x;
  point.y = size[1] - y - 1;

  if (ClientToScreen(this->WindowId, &point))
    {
    SetCursorPos(point.x, point.y);
    }
}

//----------------------------------------------------------------------------
void vtkWin32OpenGLRenderWindow::SetCurrentCursor(int shape)
{
  if ( this->InvokeEvent(vtkCommand::CursorChangedEvent,&shape) )
    {
    return;
    }
  this->Superclass::SetCurrentCursor(shape);
  LPCTSTR cursorName = 0;
  switch (shape)
    {
    case VTK_CURSOR_DEFAULT:
    case VTK_CURSOR_ARROW:
      cursorName = IDC_ARROW;
      break;
    case VTK_CURSOR_SIZENE:
    case VTK_CURSOR_SIZESW:
      cursorName = IDC_SIZENESW;
      break;
    case VTK_CURSOR_SIZENW:
    case VTK_CURSOR_SIZESE:
      cursorName = IDC_SIZENWSE;
      break;
    case VTK_CURSOR_SIZENS:
      cursorName = IDC_SIZENS;
      break;
    case VTK_CURSOR_SIZEWE:
      cursorName = IDC_SIZEWE;
      break;
    case VTK_CURSOR_SIZEALL:
      cursorName = IDC_SIZEALL;
      break;
    case VTK_CURSOR_HAND:
#if(WINVER >= 0x0500)      
      cursorName = IDC_HAND;
#else
      cursorName = IDC_ARROW;
#endif
      break;
    case VTK_CURSOR_CROSSHAIR:
      cursorName = IDC_CROSS;
      break;
    }
  
  if (cursorName)
    {
    HANDLE cursor = 
      LoadImage(0,cursorName,IMAGE_CURSOR,0,0,LR_SHARED | LR_DEFAULTSIZE);
    SetCursor((HCURSOR)cursor);
    }
}
