screenshots

[arthurprs]

im developing an app that take screenshots of games,
at the moment i use this method, but it don't work in some windows vista/seven systems

function GetPrintScreen(wnd: HWND): TBitmap;
var
  h, w: Integer;
  dc: HDC;
  rect: TRect;
begin
  dc := GetDC(wnd);
  if (dc = 0) or (not GetClientRect(wnd, rect)) then
  begin
    Result := nil;
    Exit;
  end;  

  w := rect.Right - rect.Left;
  h := rect.Bottom - rect.Top;

  Result := TBitmap.Create;
  Result.Width := w;
  Result.Height := h;

  BitBlt(
    Result.Canvas.Handle, 0, 0,
    w, h,
    dc, 0, 0,
    SRCCOPY);

  ReleaseDC(wnd, dc);
end;

so,
someone know another way to get screenshots?

[jdarling]

Google code search returns the following:

procedure MakeDesktopScreenshot( const FN : string );
var
  DesktopDC : HDC;
  myBitmap : TBitmap;
  ScreenHandle : HWND;
begin
  myBitmap := TBitmap.Create;
  try
    ScreenHandle := GetDesktopWindow;
    DesktopDC := GetDC( ScreenHandle );
    try
      myBitmap.Width := screen.Width;
      myBitmap.Height := screen.Height;
      BitBlt( myBitmap.Canvas.Handle, 0, 0, screen.Width, screen.Height, DesktopDC, 0, 0, SRCCOPY );
      if &#40; FN <> '' &#41; then
        myBitmap.SaveToFile&#40; FN &#41;
      else
        Clipboard.Assign&#40; myBitmap &#41;;
    finally
      ReleaseDC&#40; ScreenHandle, DesktopDC &#41;;
    end;
  finally
    myBitmap.Free;
  end;
end; // MakeDesktopScreenshot



procedure MakeFormScreenshot&#40;hWindow&#58; HWND; const Filename &#58; string &#41;;
var
  Left, Top, Width, Height&#58; Word;
  R&#58; TRect;
  dc&#58; HDC;
  lpPal&#58; PLOGPALETTE;
  BM &#58; TBitmap;
begin
  &#123;Check if valid window handle&#125;
  if not IsWindow&#40;hWindow&#41; then Exit;
  &#123;Retrieves the rectangular coordinates of the specified window&#125;
  GetWindowRect&#40;hWindow, R&#41;;
  Left &#58;= R.Left;
  Top &#58;= R.Top;
  Width &#58;= R.Right - R.Left;
  Height &#58;= R.Bottom - R.Top;

  &#123;get the screen dc&#125;
  dc &#58;= GetDc&#40;0&#41;;
  if &#40;dc = 0&#41; then
    exit;


  BM &#58;= TBitmap.Create;
  try

    bm.Width  &#58;= Width;
    bm.Height &#58;= Height;

    &#123;do we have a palette device?&#125;
    if &#40;GetDeviceCaps&#40;dc, RASTERCAPS&#41; and
      RC_PALETTE = RC_PALETTE&#41; then
    begin
      &#123;allocate memory for a logical palette&#125;
      GetMem&#40;lpPal,
        SizeOf&#40;TLOGPALETTE&#41; +
      &#40;255 * SizeOf&#40;TPALETTEENTRY&#41;&#41;&#41;;
      &#123;zero it out to be neat&#125;
      FillChar&#40;lpPal^,
        SizeOf&#40;TLOGPALETTE&#41; +
      &#40;255 * SizeOf&#40;TPALETTEENTRY&#41;&#41;,
        #0&#41;;
      &#123;fill in the palette version&#125;
      lpPal^.palVersion &#58;= $300;
      &#123;grab the system palette entries&#125;
      lpPal^.palNumEntries &#58;=
        GetSystemPaletteEntries&#40;dc,
        0,
        256,
        lpPal^.palPalEntry&#41;;
      if &#40;lpPal^.PalNumEntries <> 0&#41; then
      begin
        &#123;create the palette&#125;
        bm.Palette &#58;= CreatePalette&#40;lpPal^&#41;;
      end;
      FreeMem&#40;lpPal, SizeOf&#40;TLOGPALETTE&#41; +
      &#40;255 * SizeOf&#40;TPALETTEENTRY&#41;&#41;&#41;;
    end;
    &#123;copy from the screen to the bitmap&#125;
    BitBlt&#40;bm.Canvas.Handle,
      0,
      0,
      Width,
      Height,
      Dc,
      Left,
      Top,
      SRCCOPY&#41;;
    &#123;release the screen dc&#125;
    ReleaseDc&#40;0, dc&#41;;

    BM.SaveToFile&#40; Filename &#41;;

  finally
    BM.Free;
  end;

end;

Haven't tried it, as usually I just include it in my games via a quick key.

[arthurprs]

jdarling, this is the same method that i use, via GDI, im searching for another way :|

[arthurprs]

after some insente googling i found that creating a opengl fullscreen context and then use glReadPixels() can work

but how can i do that?
thanks.

[chronozphere]

Google is your friend.

http://www.gamedev.net/community/for...opic_id=436385

[arthurprs]

Google is your friend.

http://www.gamedev.net/community/for...opic_id=436385

hi chronozphere, i found how to capture the screenshots,
but i don't know how to create a opengl fullscreen context over the current running game window

[KidPaddle]

Only German, but with samples for saving screenshots to bmp or tga file format.

http://wiki.delphigl.com/index.php/Screenshot

I try to translate the comments for bimtap version

procedure ScreenShot(const Name : string);
var 
  F : file;
  FileInfo: BITMAPINFOHEADER;
  FileHeader : BITMAPFILEHEADER;
  pPicData:Pointer;
  Viewport : array[0..3] of integer;
begin
  // clear header
  ZeroMemory(@FileHeader, SizeOf(BITMAPFILEHEADER));
  ZeroMemory(@FileInfo, SizeOf(BITMAPINFOHEADER));
 
  // query screen size of viewpoint 
  glGetIntegerv(GL_VIEWPORT, @Viewport);
 
  // Init header
  FileHeader.bfType := 19778; //$4D42 = 'BM'
  FileHeader.bfOffBits := SizeOf(BITMAPINFOHEADER)+SizeOf(BITMAPFILEHEADER);
 
  // setup bitmap header
  FileInfo.biSize := SizeOf(BITMAPINFOHEADER);
  FileInfo.biWidth := Viewport[2];
  FileInfo.biHeight := Viewport[3];
  FileInfo.biPlanes := 1;
  FileInfo.biBitCount := 32;
  FileInfo.biSizeImage := FileInfo.biWidth*FileInfo.biHeight*(FileInfo.biBitCount div 8);
 
  // setup file size
  FileHeader.bfSize := FileHeader.bfOffBits + FileInfo.biSizeImage;
 
  // get memory for image
  GetMem(pPicData, FileInfo.biSizeImage);
  try
    // read pixels from opengl frame buffer
    glReadPixels(0, 0, Viewport[2], Viewport[3], GL_BGRA, GL_UNSIGNED_BYTE, pPicData);
 
    // write image to disk, modern version are using streams
    AssignFile(f, name);
    Rewrite( f,1 );
    try
     BlockWrite(F, FileHeader, SizeOf(BITMAPFILEHEADER));
     BlockWrite(F, FileInfo, SizeOf(BITMAPINFOHEADER));
     BlockWrite(F, pPicData^, FileInfo.biSizeImage );
    finally
      CloseFile(f);
    end;
  finally
    // free reserved pixel data
    FreeMem(pPicData, FileInfo.biSizeImage);
  end;
end;