[info-performer] Solution memory leak caused by GetDC()

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From: Peter Krueger (pkrueger++at++appss.de)
Date: 04/23/2004 05:33:59

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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