Norman Vine wrote: > Andy Ross writes: > > [* What, exactly, does game mode do? My impression was that it simply > > set the video mode through GDI before creating the OpenGL context. > > This isn't an optimization, per se. Can someone more familiar with > > GLUT comment?] > > > In Windows it does > > status = ChangeDisplaySettings(¤tDm->devmode, > CDS_FULLSCREEN); > > Which is the FAST lane to the underlying video > in that the Win32 Windowing manager is bypassed > for this window < ie all the region clipping code etc. > > so the speedup is not a driver bug !
Uh oh, we're going in circles again. Last words, I promise. :) I understand what you mean. That's exactly the optimization I'm talking about (being able to skip all the regular blit mechanisms in favor of a full screen page flip). But honestly, this optimization doesn't do as much as you think it does. The proof (really, proof) of this is the fact that the X11 drivers, (and many drivers under windows I expect), don't show this behavior. Modern cards are very, very fast. They have gobs of memory bandwidth to blow on something as simple (heh) as a 1024x768 screen blit, and do masking and clipping in dedicated hardware that pipelines with the blit for essentially zero cost. Four or more years ago, your point would have been valid. The page flip optimization could easily mean a 30% increase in frame rate for a 72 Hz game (these are complete fabricated numbers, but in the ballpark). But it's just not like that anymore; really. It's a mild optimization at best. Andy -- Andrew J. Ross NextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
