Open GL dialog jpg dump

[Petr Schreiber jr]

Hi Dean,

I have used the viewport to expand the Open GL dialog beyond the native screen size, however, the bmp capture seems only limited to the native screen size, irrelevant of the Open GL dialog size.

According to OpenGL specs, the pixels rendered in areas covered by other window or out of screen are undefined.
So the solution would be to do some offscreen rendering ( not swapping buffers, just rendering to texture / glReadPixels ) using few passes, which would shift camera to get whole image.


Hope this helped,
Petr

[Dale Yarker]

... if your program could relocate the Open GL window, then it could grab the visable pieces and patch them together.

A brain storm I had on bus to work after previous post. Even if totally wrong, somebody else might give you a better answer while proving me wrong!

Good luck with the project.

Cheers,

[Dale Yarker]

You mean the window and the window contents right? Like pressing <alt><print screen> then pasteing into Paint?

Just tried <alt><print screen>, and it only returns the on screen part, same as your code does. Consider that the off screen part does not exist in video buffer (either main RAM or video board RAM). Windows would draw only the visable portion; and as you grab the window with mouse and move it Windows redraws it.

If you mean just the contents, like the behavier of GRAPHIC GET BITS on PB GRAPHIC control or window, then the other program would have to cooperate.

[dean goodman]

I guess no one has ventured to answer since perhaps I did not explain the problem well enough. How does one make a bmp capture of the entire Open GL dialog beyond the visible portions of the screen.

I have used the viewport to expand the Open GL dialog beyond the native screen size, however, the bmp capture seems only limited to the native screen size, irrelevant of the Open GL dialog size.

Any help would be appreciated... I have included my bmp capture, and some initialization...In the example the dwidth/dheight is arbitrarily set to 2 times the native screen resolution. The capture however, is only the visible screen portion!


'******************************************************************************
SUB SizeOpenGL(BYVAL dWidth AS DWORD, BYVAL dHeight AS DWORD)
'******************************************************************************

glViewport 0,0,dWidth,dHeight
glMatrixMode gl_PROJECTION
glLoadIdentity
gluPerspective (45.0,dWidth/dHeight,0.1,150.0)
glMatrixMode gl_MODELVIEW
glLoadIdentity

END SUB

'******************************************************************************
FUNCTION InitOpenGL(BYVAL dWidth AS DWORD, BYVAL dHeight AS DWORD) AS LONG
'******************************************************************************

IF PixelFormatSetup() THEN
hPicRC = wglCreateContext (hPicDC)
IF hPicRC THEN
wglMakeCurrent hPicDC, hPicRC
glEnable GL_DEPTH_TEST
SizeOpenGL dwidth, dheight
FUNCTION = %True
EXIT FUNCTION
END IF
END IF

FUNCTION = %False

END FUNCTION


'*******************************************************************************
FUNCTION InitDialog(BYVAL hdlg AS DWORD) AS LONG
'*******************************************************************************

LOCAL x AS DWORD
LOCAL y AS DWORD

CONTROL HANDLE hdlg, %id_glidpic TO hPic
hPicDC = GetDC(hPic)

dwidth=2*lxl
dheight=2*lyl
IF InitOpenGL (dwidth, dheight) THEN
FUNCTION = %True
EXIT FUNCTION
END IF
FUNCTION = %False

END FUNCTION



FUNCTION openglvolumescreencapture AS LONG

LOCAL ret AS LONG
LOCAL hBMPDC AS LONG
LOCAL hMemDC AS LONG
LOCAL rc AS RECT
LOCAL hMemBmp AS LONG
LOCAL bm AS BITMAP
LOCAL bmi AS BITMAPINFO
LOCAL bmpFileHdr AS BITMAPFILEHEADER
LOCAL bmpInfoHdr AS BITMAPINFOHEADER
LOCAL hFile AS LONG
LOCAL sbmpfile$
LOCAL xx1 AS LONG
LOCAL yy1 AS LONG

sbmpfile$=ioutput$+opgl3dident$+".bmp"
DIALOG SET TEXT hdlggl3d,opgl3dident$+".jpg"
GetclientRect hdlggl3d, rc


DIALOG GET LOC hdlggl3d TO xx1,yy1
DIALOG UNITS hdlggl3d, xx1,yy1 TO PIXELS xx1,yy1

rc.ntop=-yy1+60 ' fix for getting the client area from the top

hBMPDC = CreateDC( "Display", BYVAL %NULL, BYVAL %NULL, BYVAL %NULL )
hMemDC = CreateCompatibleDC( hBMPDC )

' showwindow(hwndmain,%sw_hide)

bmi.bmiHeader.biSize = SIZEOF( bmi.bmiHeader )
bmi.bmiHeader.biWidth = (rc.nRight - rc.nLeft)
bmi.bmiHeader.biHeight = (rc.nBottom - rc.nTop)
bmi.bmiHeader.biPlanes = 1
bmi.bmiHeader.biBitCount = 24
bmi.bmiHeader.biCompression = %BI_RGB

hMemBmp = CreateDIBSection( hMemDC, bmi, %DIB_RGB_COLORS, 0, 0, 0 )
GlobalLock hMemBmp
SelectObject hMemDC, hMemBmp
GetObject hMemBmp, SIZEOF( bm ), bm
BitBlt hMemDC, 0,0, bm.bmwidth, bm.bmheight, hBMPDC, rc.nLeft, rc.nTop, %SRCCOPY
bmpFileHdr.bfType = CVI( "BM" )
bmpFileHdr.bfSize = LEN( bmpFileHdr ) + LEN( bmpInfoHdr ) + bm.bmWidthBytes * bm.bmHeight
bmpFileHdr.bfOffBits = 54
bmpInfoHdr.biSize = 40
bmpInfoHdr.biWidth = bm.bmWidth
bmpInfoHdr.biHeight = bm.bmHeight
bmpInfoHdr.biPlanes = 1
bmpInfoHdr.biBitCount = 24
bmpInfoHdr.biSizeImage = 54 + bm.bmWidthBytes * bm.bmHeight

'Write to disk
hFile = FREEFILE
ERRCLEAR
OPEN sBmpFile$ FOR OUTPUT AS #hFile
PRINT #hFile, bmpFileHdr bmpInfoHdr _
PEEK$( bm.bmBits, bm.bmWidthBytes * bm.bmHeight );
CLOSE hFile

IF ERR THEN ret = %False ELSE ret = %True

DeleteDC hBMPDC: DeleteDC hMemDC: GlobalUnlock hMemBmp: DeleteObject hMemBmp

volumebmptojpeg

FUNCTION = ret

' showwindow(hwndmain,%sw_show)

END FUNCTION

[dean goodman]

Hi, I have been able to make screen dumps of Open GL dialogs in PB. However, I need to make jpg dumps of the graphic dialog and not just the displayed screen portion. I need to make a jpg output of areas not displayed to get a better DPI. Does any one know of any examples Open GL source code to accomplish this. Thx