// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: fabdxlib.c 1257 2016-09-20 17:14:21Z wesleyjohnson $
//
// Copyright (C) 1998-2016 by DooM Legacy Team.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
//
// $Log: fabdxlib.c,v $
// Revision 1.5  2001/03/30 17:12:52  bpereira
// Revision 1.4  2001/03/03 06:17:34  bpereira
// Revision 1.3  2000/09/01 19:34:37  bpereira
// Revision 1.2  2000/02/27 00:42:12  hurdler
// Revision 1.1.1.1  2000/02/22 20:32:33  hurdler
// Initial import into CVS (v1.29 pr3)
//
//
// DESCRIPTION:
//      faB's DirectX library v1.0
//      - converted to C for Doom Legacy
//
//-----------------------------------------------------------------------------

// Because of WINVER redefine, doomtype.h (via doomincl.h) is before any
// other include that might define WINVER
#include "doomincl.h"

#include "win_main.h"
#include "fabdxlib.h"
#include "dx_error.h"
#include <windows.h>
#include <windowsx.h>
#include <ddraw.h>
#include "i_system.h"

#define NT4COMPAT   //always defined, always compatible


// globals

#if 1
LPDIRECTDRAW2                   DDr2 = NULL;
LPDIRECTDRAWSURFACE             ScreenReal = NULL;              // DirectDraw primary surface
LPDIRECTDRAWSURFACE             ScreenVirtual = NULL;           // DirectDraw back surface
LPDIRECTDRAWPALETTE             DDPalette = NULL;               // The primary surface palette
LPDIRECTDRAWCLIPPER             windclip = NULL;                // clipper for windowed mode
#else
IDirectDraw2*                   DDr2 = NULL;
IDirectDrawSurface*             ScreenReal = NULL;              // DirectDraw primary surface
IDirectDrawSurface*             ScreenVirtual = NULL;           // DirectDraw back surface
IDirectDrawPalette*             DDPalette = NULL;               // The primary surface palette
IDirectDrawClipper*             windclip = NULL;                // clipper for windowed mode
#endif

BOOL   fdx_fullscreen;  // true for fullscreen exclusive mode,

int                             windowPosX = 0;                 // current position in windowed mode
int                             windowPosY = 0;

int                             ScreenWidth;    
int                             ScreenHeight;
BOOL                            ScreenLocked;                   // Screen surface is being locked
int                             ScreenPitch;                    // offset from one line to the next
unsigned char*                  ScreenPtr;                      // memory of the surface

#define SAFE_RELEASE(x) if(x != NULL) { x->lpVtbl->Release(x); x = NULL; }
#define SAFE_DELETE(x) if(x != NULL) { delete x; x = NULL; }

//
// CreateNewSurface
//
IDirectDrawSurface* create_draw_surface(int dwWidth,
                                     int dwHeight,
                                     int dwSurfaceCaps)
{
    DDSURFACEDESC       ddsd;
    HRESULT             hr;
    //    DDCOLORKEY          ddck;
    LPDIRECTDRAWSURFACE psurf;
    
    ZeroMemory(&ddsd, sizeof(ddsd));
    ddsd.dwSize = sizeof(ddsd);
    ddsd.dwFlags = DDSD_CAPS | DDSD_HEIGHT |DDSD_WIDTH;
    
    ddsd.ddsCaps.dwCaps = dwSurfaceCaps;
    
    ddsd.dwHeight = dwHeight;
    ddsd.dwWidth = dwWidth;
    
    hr = DDr2->lpVtbl->CreateSurface (DDr2, &ddsd, &psurf, NULL);
    
    if( hr == DD_OK )
    {
        psurf->lpVtbl->Restore(psurf);
        
        //hr = ScreenReal->lpVtbl->GetColorKey(DDCKEY_SRCBLT, &ddck);
        //psurf->SetColorKey(DDCKEY_SRCBLT, &ddck);
    }
    else
        psurf = NULL;
    
    return psurf;
}


#ifdef ENUM_DIRECT_DRAW_DEV
//
// hmm.. I've got just one device 'Pilote d'affichage principal'
//
BOOL WINAPI myEnumDDDevicesCallback (GUID FAR*lpGUID,
                                     LPSTR lpDriverDescription,
                                     LPSTR lpDriverName,
                                     LPVOID lpContext)
{
    CONS_Printf ("Driver desc: %s\n"
        "       name: %s\n", lpDriverDescription, lpDriverName);
    
    return DDENUMRET_OK;
}
#endif


//
// wow! from 320x200x8 up to 1600x1200x32 thanks Banshee! :)
//
// Called by EnumDisplayModes, passing appFunc in lpContext
// DirectDraw 2, 3
HRESULT WINAPI FDX_local_enum_mode_callback (LPDDSURFACEDESC surf, LPVOID lpContext)
{
    // Call the user callback, with (width, height, bbp)
    BOOL cont = ((FDX_enum_mode_callback)lpContext) (
        surf->dwWidth,
        surf->dwHeight,
        surf->ddpfPixelFormat.dwRGBBitCount);

    // continue or stop
    return  (cont)? DDENUMRET_OK : DDENUMRET_CANCEL;
}


//
// Application call here to enumerate display modes
//
BOOL FDX_EnumDisplayModes (FDX_enum_mode_callback appFunc)
{
    if (DDr2==NULL)
        return FALSE;
    
    // enumerate display modes
    // Carl: DirectX 3.x apparently does not support VGA modes. Who cares. :)
    // faB: removed DDEDM_REFRESHRATES, detects too many modes, plus we don't care of refresh rate.
    // Enumerate passes appFunc to FDX_enum_mode_callback()
    if( have_DX0300 )
        DDr2->lpVtbl->EnumDisplayModes (DDr2, 0 /*| DDEDM_REFRESHRATES*/,
                      NULL, (void*)appFunc, FDX_local_enum_mode_callback);
    else
        DDr2->lpVtbl->EnumDisplayModes (DDr2, DDEDM_STANDARDVGAMODES /*| DDEDM_REFRESHRATES*/,
                      NULL, (void*)appFunc, FDX_local_enum_mode_callback);
    return TRUE;
}


//
// Create the DirectDraw object for later
//
void FDX_create_main_instance (void)
{
    HRESULT hr;
    IDirectDraw* cDDr;

    if( DDr2 )  return;  // already have main instance

    //
    // create an instance of DirectDraw object
    //
    if (FAILED(hr = DirectDrawCreate(NULL, &cDDr, NULL)))
        I_Error ("DirectDrawCreate FAILED: %s", DXErrorToString(hr));
    
    // change interface to IDirectDraw2
    if (FAILED(hr = cDDr->lpVtbl->QueryInterface (cDDr, &IID_IDirectDraw2, (LPVOID*)&DDr2)))
        I_Error("Failed to query DirectDraw2 interface: %s", DXErrorToString(hr));
    
    // release the interface we don't need
    cDDr->lpVtbl->Release (cDDr);
}


//
// - DirectDraw is initialized properly, or I_Error
//
BOOL  FDX_InitDDMode (HWND appWin, int width, int height, int bpp, int fullScr)
{
    char *  reason;
    DDSURFACEDESC   ddsd;  // DirectDraw surface description for allocating
    DDSCAPS         ddscaps;
    HRESULT         ddrval;
    
    DWORD           dwStyle;
    RECT            rect;
    
#ifdef ENUM_DIRECT_DRAW_DEV
    // enumerate directdraw devices
    if ( FAILED(DirectDrawEnumerate (myEnumDDDevicesCallback, NULL)))
          I_Error ("Error with DirectDrawEnumerate");
#endif
    
    if (!DDr2)
        FDX_create_main_instance();
    
    // remember what screen mode we are in
    fdx_fullscreen = fullScr;
    ScreenHeight = height;
    ScreenWidth = width;
    
    if (fdx_fullscreen)
    {
        // Change window attributes
        dwStyle = WS_POPUP | WS_VISIBLE;
        SetWindowLong (appWin, GWL_STYLE, dwStyle);
        SetWindowPos(appWin, HWND_TOPMOST, 0, 0, 0, 0,
	    SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER);
        
        // Get exclusive mode
        ddrval = DDr2->lpVtbl->SetCooperativeLevel(DDr2, appWin,
	    DDSCL_EXCLUSIVE | DDSCL_FULLSCREEN | DDSCL_ALLOWREBOOT);
        if (ddrval != DD_OK)
        {
	    reason = "Set cooperative";
	    goto fail_msg;
	}
        
        // Switch from windows desktop to fullscreen
        
#ifdef NT4COMPAT
        ddrval = DDr2->lpVtbl->SetDisplayMode(DDr2, width, height, bpp, 0, 0);
#else
        ddrval = DDr2->lpVtbl->SetDisplayMode(DDr2, width, height, bpp, 0, DDSDM_STANDARDVGAMODE);
#endif
        if (ddrval != DD_OK)
        {
	    reason = "Set display mode";
	    goto fail_msg;
	}
        
        // This is not really needed, except in certain cases. One case
        // is while using MFC. When the desktop is initally at 16bpp, a mode
        // switch to 8bpp somehow causes the MFC window to not fully initialize
        // and a CreateSurface will fail with DDERR_NOEXCLUSIVEMODE. This will
        // ensure that the window is initialized properly after a mode switch.
        
        ShowWindow(appWin, SW_SHOW);
        
        // Create the primary surface with 1 back buffer. Always zero the
        // DDSURFACEDESC structure and set the dwSize member!
        
        ZeroMemory(&ddsd, sizeof(ddsd));
        ddsd.dwSize = sizeof(ddsd);
        ddsd.dwFlags = DDSD_CAPS | DDSD_BACKBUFFERCOUNT;
        ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE | DDSCAPS_FLIP | DDSCAPS_COMPLEX;
        
        // for fullscreen we use page flipping, for windowed mode, we blit the hidden surface to
        // the visible surface, in both cases we have a visible (or 'real') surface, and a hidden
        // (or 'virtual', or 'backbuffer') surface.
        ddsd.dwBackBufferCount = 1;
        
        ddrval = DDr2->lpVtbl->CreateSurface(DDr2,&ddsd, &ScreenReal, NULL);
        if (ddrval != DD_OK)
        {
	    reason = "Create primary surface";
	    goto fail_msg;
	}
        
        // Get a pointer to the back buffer
        
        ddscaps.dwCaps = DDSCAPS_BACKBUFFER;
        ddrval = ScreenReal->lpVtbl->GetAttachedSurface(ScreenReal,&ddscaps, &ScreenVirtual);
        if (ddrval != DD_OK)
        {
	    reason = "Surface attach";
	    goto fail_msg;
	}
    }
    else
    {
        // windowed
        rect.top = 0;
        rect.left = 0;
        rect.bottom = height-1;
        rect.right = width-1;
        
        // Change window attributes
        
        dwStyle = GetWindowStyle(appWin);
        dwStyle &= ~WS_POPUP;
        dwStyle |= WS_OVERLAPPED | WS_SYSMENU | WS_CAPTION;
        
        SetWindowLong(appWin, GWL_STYLE, dwStyle);
        
        // Resize the window so that the client area is the requested width/height
        
        AdjustWindowRectEx(&rect, GetWindowStyle(appWin), GetMenu(appWin) != NULL,
            GetWindowExStyle(appWin));
        
        // Just in case the window was moved off the visible area of the
        // screen.
        
        SetWindowPos(appWin, NULL, 0, 0, rect.right - rect.left,
            rect.bottom-rect.top, SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
        
        SetWindowPos(appWin, HWND_NOTOPMOST, 0, 0, 0, 0,
            SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
        
        // Exclusive mode is normal since it's in windowed mode and needs
        // to cooperate with GDI
        
        ddrval = DDr2->lpVtbl->SetCooperativeLevel(DDr2,appWin, DDSCL_NORMAL );
        if (ddrval != DD_OK)
        {
	    reason = "Set cooperative";
	    goto fail_msg;
	}
        
        // Always zero the DDSURFACEDESC structure and set the dwSize member!
        
        ZeroMemory(&ddsd, sizeof(ddsd));
        ddsd.dwSize = sizeof(ddsd);
        ddsd.dwFlags = DDSD_CAPS;
        ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;
        
        // Create the primary surface
        
        ddrval = DDr2->lpVtbl->CreateSurface(DDr2,&ddsd, &ScreenReal, NULL);
        if (ddrval != DD_OK)
        {
	    reason = "Create primary surface";
	    goto fail_msg;
	}
        
        // Create a back buffer for offscreen rendering, this will be used to
        // blt to the primary
        
        ScreenVirtual = create_draw_surface(width, height, DDSCAPS_OFFSCREENPLAIN |
            DDSCAPS_SYSTEMMEMORY );
        if (ScreenVirtual == NULL)
        {
	    reason = "Create second surface";
	    goto fail_msg;
	}
        
        
        //TODO: get the desktop bit depth, and build a lookup table
        // for quick conversions of 8bit color indexes 0-255 to desktop colors
        // eg: 256 entries of equivalent of palette colors 0-255 in 15,16,24,32 bit format
        // when blit virtual to real, convert pixels through lookup table..
        
        
        // Use a clipper object for clipping when in windowed mode
        // (make sure our drawing doesn't affect other windows)
        
        ddrval = DDr2->lpVtbl->CreateClipper (DDr2, 0, &windclip, 0);
        if (ddrval != DD_OK)
        {
	    reason = "Clipper create";
	    goto fail_msg;
	}
        
        // Associate the clipper with the window.
        ddrval = windclip->lpVtbl->SetHWnd (windclip,0, appWin);
        if (ddrval != DD_OK)
        {
	    reason = "Clipper set window";
	    goto fail_msg;
	}
        
        // Attach the clipper to the surface.
        ddrval = ScreenReal->lpVtbl->SetClipper (ScreenReal,windclip);
        if (ddrval != DD_OK)
        {
	    reason = "Clipper attach surfce";
	    goto fail_msg;
	}
    }
    return true;
 
fail_msg:
    I_SoftError( "InitMode FAILED: %s, %s\n", reason, DXErrorToString(ddrval));
    return false;
}


//
// Free all memory
//
void  FDX_CloseDirectDraw (void)
{
    if (DDr2 != NULL)
    {
        SAFE_RELEASE (windclip);
        SAFE_RELEASE (DDPalette);
        
        // If the app is fullscreen, the back buffer is attached to the
        // primary. Releasing the primary buffer will also release any
        // attached buffers, so explicitly releasing the back buffer is not
        // necessary.
        
        if (!fdx_fullscreen)
            SAFE_RELEASE (ScreenVirtual);   // release hidden surface
        SAFE_RELEASE (ScreenReal);                      // and attached backbuffers for fdx_fullscreen mode
        DDr2->lpVtbl->Release(DDr2);
        DDr2 = NULL;
    }
}


//
// Release DirectDraw stuff before display mode change
//
void   FDX_ReleaseChtuff (void)
{
    if (DDr2 != NULL)
    {
        SAFE_RELEASE (windclip);
        SAFE_RELEASE (DDPalette);
        
        // If the app is fullscreen, the back buffer is attached to the
        // primary. Releasing the primary buffer will also release any
        // attached buffers, so explicitly releasing the back buffer is not
        // necessary.
        
        if (!fdx_fullscreen)
            SAFE_RELEASE (ScreenVirtual);   // release hidden surface
        SAFE_RELEASE (ScreenReal);                      // and attached backbuffers for fdx_fullscreen mode
    }
}


//
// Clear the surface to color
//
void  FDX_ClearSurface (IDirectDrawSurface* surface, int color)
{
    DDBLTFX             ddbltfx;
    
    // Use the blter to do a color fill to clear the back buffer
    ddbltfx.dwSize = sizeof(ddbltfx);
    ddbltfx.dwFillColor = color;
    surface->lpVtbl->Blt(surface,NULL, NULL, NULL, DDBLT_COLORFILL | DDBLT_WAIT, &ddbltfx);
    
}


//
// Flip the real page with virtual page
// - in fdx_fullscreen mode, do page flipping
// - in windowed mode, copy the hidden surface to the visible surface
//
// waitflip : if not 0, wait for page flip to end
void  FDX_ScreenFlip (int waitflip)
{
    HRESULT hr;
    RECT    rect;
    
    if (fdx_fullscreen)
    {               
        //hr = ScreenReal->lpVtbl->GetFlipStatus (ScreenReal, DDGFS_);
        
        // In full-screen exclusive mode, do a hardware flip.
        hr = ScreenReal->lpVtbl->Flip(ScreenReal, NULL, DDFLIP_WAIT);   //return immediately
        
        // If the surface was lost, restore it.
        if (hr == DDERR_SURFACELOST)
        {
            ScreenReal->lpVtbl->Restore(ScreenReal);
            
            // The restore worked, so try the flip again.
            hr = ScreenReal->lpVtbl->Flip(ScreenReal, 0, DDFLIP_WAIT);
        }
    }
    else
    {
        rect.left = windowPosX;
        rect.top = windowPosY;
        rect.right = windowPosX + ScreenWidth - 1;
        rect.bottom = windowPosY + ScreenHeight - 1;
        
        // Copy the back buffer to front.
        hr = ScreenReal->lpVtbl->Blt(ScreenReal,&rect, ScreenVirtual, 0, DDBLT_WAIT, 0);
        
        if (hr!=DD_OK)
        {
            // If the surfaces were lost, restore them.
            if (ScreenReal->lpVtbl->IsLost(ScreenReal) == DDERR_SURFACELOST)                        
                ScreenReal->lpVtbl->Restore(ScreenReal);
            
            if (ScreenVirtual->lpVtbl->IsLost(ScreenVirtual) == DDERR_SURFACELOST)
                ScreenVirtual->lpVtbl->Restore(ScreenVirtual);
            
            // Retry the copy.
            hr = ScreenReal->lpVtbl->Blt(ScreenReal,&rect, ScreenVirtual, 0, DDBLT_WAIT, 0);
        }
    }
    
    if (hr != DD_OK)
        I_Error ("ScreenFlip() : couldn't Flip surfaces");
}


//
// Print a text to the surface
//
void TextPrint (int x, int y, char* message)
{
    HRESULT hr;
    HDC             hdc = NULL;
    
    // Get the device context handle.
    hr = ScreenVirtual->lpVtbl->GetDC(ScreenVirtual,&hdc);
    if (hr != DD_OK)
        return;
    
    // Write the message.
    SetBkMode(hdc, TRANSPARENT);
    SetTextColor(hdc, RGB(255, 255, 255));
    TextOut(hdc, x, y, message, strlen(message));
    
    // Release the device context.
    hr = ScreenVirtual->lpVtbl->ReleaseDC(ScreenVirtual,hdc);
}


//
// Lock surface before multiple drawings by hand, for speed
//
BOOL  FDX_LockScreen(void)
{
    DDSURFACEDESC  ddsd;
    HRESULT        ddrval;
    
    memset( &ddsd, 0, sizeof( ddsd ));
    ddsd.dwSize = sizeof( ddsd );
    
    // attempt to Lock the surface
    ddrval = ScreenVirtual->lpVtbl->Lock(ScreenVirtual, NULL, &ddsd, DDLOCK_WAIT, NULL);
    
    // Always, always check for errors with DirectX!
    
    // If the surface was lost, restore it.
    if (ddrval == DDERR_SURFACELOST)
    {
        ddrval = ScreenReal->lpVtbl->Restore (ScreenReal);
        
        // now retry to get the lock
        ddrval = ScreenVirtual->lpVtbl->Lock(ScreenVirtual, NULL, &ddsd, DDLOCK_WAIT, NULL);
    }
    
    if( ddrval == DD_OK )
    {
        ScreenLocked = TRUE;
        ScreenPtr    = (unsigned char*)ddsd.lpSurface;
        ScreenPitch = ddsd.lPitch;
    }
    else
    {
        ScreenLocked = FALSE;
        ScreenPtr        = NULL;
        ScreenPitch = 0;
        //I_Error ("LockScreen() : couldn't restore the surface.");
        return false;
    }
    return true;
}


//
// Unlock surface
//
void FDX_UnlockScreen(void)
{
    if (DD_OK != ScreenVirtual->lpVtbl->Unlock(ScreenVirtual,NULL))
        I_Error ("Couldn't UnLock the renderer!");
    
    ScreenLocked = FALSE;
    ScreenPtr    = NULL;
    ScreenPitch = 0;
}


// Blit virtual screen to real screen
//faB: note: testing 14/03/1999, see if it is faster than memcopy of virtual to 
/*
static    LPDIRECTDRAWSURFACE lpDDS = NULL;
void BlitScreen (void)
{
    HRESULT hr;

    if (!lpDDS)
        I_Error ("lpDDS NULL");

    hr = ScreenVirtual->lpVtbl->BltFast(ScreenVirtual,
                    0, 0,    // Upper left xy of destination
                    lpDDS, // Source surface
                    NULL,        // Source rectangle = entire surface
                    DDBLTFAST_WAIT | DDBLTFAST_NOCOLORKEY );
    if (FAILED(hr))
        I_Error ("BltFast FAILED");
}


void MakeScreen (int width, int height, BYTE* lpSurface)
{
    HRESULT hr;
    DDSURFACEDESC    ddsd;

    // Initialize the surface description.
    ZeroMemory (&ddsd, sizeof(ddsd));
    ZeroMemory (&ddsd.ddpfPixelFormat, sizeof(DDPIXELFORMAT));
    ddsd.dwSize = sizeof(ddsd);
    ddsd.dwFlags = DDSD_WIDTH | DDSD_HEIGHT | //DDSD_LPSURFACE |
                   DDSD_PITCH | DDSD_PIXELFORMAT | DDSD_CAPS;
    ddsd.dwWidth = width;
    ddsd.dwHeight= height;
    ddsd.lPitch  = width;
    ddsd.lpSurface = lpSurface;
    ddsd.ddsCaps.dwCaps = DDSCAPS_SYSTEMMEMORY | DDSCAPS_OFFSCREENPLAIN;
 
    // Set up the pixel format for 8-bit
    ddsd.ddpfPixelFormat.dwSize = sizeof(DDPIXELFORMAT);
    ddsd.ddpfPixelFormat.dwFlags= DDPF_RGB | DDPF_PALETTEINDEXED8;
    ddsd.ddpfPixelFormat.dwRGBBitCount = 8;

    //
      ddsd.ddpfPixelFormat.dwRGBBitCount = (DWORD)DEPTH*8;
    ddsd.ddpfPixelFormat.dwRBitMask    = 0x00FF0000;
    ddsd.ddpfPixelFormat.dwGBitMask    = 0x0000FF00;
    ddsd.ddpfPixelFormat.dwBBitMask    = 0x000000FF;
 
    // Create the surface
    hr = DDr2->lpVtbl->CreateSurface (DDr2, &ddsd, &lpDDS, NULL);
    if (FAILED(hr))
        I_Error ("MakeScreen FAILED: %s",DDError(hr));
    //ddsd.lpSurface = lpSurface;
}
*/

//
// Create a palette object
// 
void FDX_CreateDDPalette (PALETTEENTRY* colorTable)
{
    HRESULT  ddrval;
    ddrval = DDr2->lpVtbl->CreatePalette(DDr2, DDPCAPS_8BIT|DDPCAPS_ALLOW256, colorTable, &DDPalette, NULL);
    if (ddrval != DD_OK)
        I_Error ("CreatePalette: %s\n", DXErrorToString(ddrval));
};


//
// Free the palette object
//
void FDX_DestroyDDPalette (void)
{
    SAFE_RELEASE(DDPalette);
}


//
// Set a a full palette of 256 PALETTEENTRY entries
//
void FDX_SetDDPalette (PALETTEENTRY* pal)
{
    // create palette first time
    if (DDPalette==NULL)
        FDX_CreateDDPalette (pal);
    else
        DDPalette->lpVtbl->SetEntries(DDPalette,0,0,256,pal);
    // setting the same palette to the same surface again does not increase
    // the reference count
    ScreenReal->lpVtbl->SetPalette (ScreenReal,DDPalette);
}


//
// Wait for vsync, gross
//
void FDX_WaitVbl (void)
{
    if( DDr2 )
        DDr2->lpVtbl->WaitForVerticalBlank (DDr2, DDWAITVB_BLOCKBEGIN, NULL);
}
