my rubberbanding code fails with Mesa7.5.1/Win32/GDI.
The code draws with XOR directly to the front buffer,
an looks like this:
// actual drawing using glBegin() glVertex() and friends omitted
The rubberband is drawn but immediately cleared.
This is because in
a BitBlt() occurs, that directly draws the rubberband,
and in the glFlush()
another BitBlt() is done, that erases everything.
Can we maybe check in wmesa_flush() whether
the current buffer is the front buffer and do not do
anything if this is the case (no idea whether this
would affect drawing to the front buffer _without_
logic op enabled, those functions must then also
Or should write_rgba_span_front() draw to a different
place, that is later copied to the screen in
On my side, I can make my code work by omitting
the glFlush(), however, I am hesitant to do so, because
if the application runs over a network, a glFlush()
seems quite appropriate for the special use case of