From: Alexandre Naaman (naaman++at++laplace.engr.sgi.com)
Date: 04/23/2004 16:48:58
On Fri, 23 Apr 2004, Peter Krueger wrote:
Hi Peter,
You're correct, we never call(ed) ReleaseDC() because we assumed that the
HWND used for rendering did in fact get created with the CS_OWNDC flag.
That being said, considering that we do allow users to specify the HWND
to use, and that may have been created without this flag, I have added
some code to check for this and call ReleaseDC() if appropriate.
I fired off a build and it was the very last check-in which made it into
Performer 3.1.1. Hopefully it does indeed fix your problem!
Thanks for the detailed explanation,
Alex.
> Hello Performer/WIN32 developers at SGI!
> I've tried to find out why Performer has this memory leak problem with
> GetDC(). So I looked into the GTK-GlExt code to see what happens there and
> why GTK doesn't have this problem. I think I've found some relevant code.
>
> The flag need_release_dc is determined in the initialization phase of the
> GtkGlWidget. I think this could be placed in setWSWindow():
> BOOLEAN need_release_dc;
> // find out whether it is a private DC
> DWORD wndclass_style = GetClassLong (hwnd, GCL_STYLE);
> if (wndclass_style & CS_OWNDC) need_release_dc = FALSE;
> else need_release_dc = TRUE;
>
>
> When OpenGL shall be enabled the following is called and the hdc is stored
> for the finalization phase:
> hdc = GetDC (hwnd);
> wglMakeCurrent(hdc, hglrc);
>
>
> When all OpenGL calls are done for this frame the following is called:
> SwapBuffers (hdc);
> // the hdc is released now if necessary
> if (need_release_dc) ReleaseDC (hwnd, hdc);
>
> I hope this will help you to improve the Windows port of Performer and
> make it work whether the window has its own HDC or not.
>
> Regards,
> Peter
> --
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