synchronous buffer swapping

[Lisa S. Avila]

Hello David,

I don't see any reason why you shouldn't make these changes. Definitely 
MakeCurrent() should be called any place where the OpenGL context might not 
be the intended one. I have been bitten by bugs related to having the wrong 
context more times than I would care to admit!

Lisa


At 03:40 PM 4/5/00, David Gobbi wrote:
>Hi Will,
>
>We have an application with several render windows, and I'm using
>the SwapBuffers flag to cause them to all update simultaneously,
>like this (apologies to non-python users):
>
># first turn off SwapBuffers and do the renders
>for renWin in renderWindows:
>   renWin.SwapBuffersOff()
>   renWin.Render()
># swap the buffers
>for renWin in renderWindows:
>   renWin.SwapBuffersOn()
>   renWin.Frame()
>
>This works nicely under UNIX, all the windows update in sync.
>However, the vtkWin32OpenGLRenderWindow ignores the SwapBuffers
>flag (it always swaps when Render or Frame is called).  Also unlike
>UNIX, on Win32 the Frame command must be proceeded by MakeCurrent
>in order to work properly.
>
>So, I was wondering if I could change vtkWin32OpenGLRenderWindow::Frame()
>so that
>   1) it checks this->SwapBuffers and
>   2) it calls this->MakeCurrent() before SwapBuffers().
>This would make it behave the same as UNIX, and (as far as I've
>tested) won't break anything.  No one has messed with the Frame()
>command for years, so I thought I should ask first...
>
>  - David
>
>--
>   David Gobbi, MSc                    dgobbi at irus.rri.on.ca
>   Advanced Imaging Research Group
>   Robarts Research Institute, University of Western Ontario
>
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