Thread: RE: [Algorithms] vrefresh jumpiness
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From: Jacob T. \(C. D. Ltd\) <JacobT@Core-Design.com> - 2004-03-25 15:17:49
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I believe this is called "multiple imaging". If your update rate = doesn't match the refresh rate then your brain is expecting the gaps = between the update frames but because they aren't there the brain gets a = bit confused and you see multiple images. If you search for=20 multiple-image suppression and look around at the evans and sutherland site you should find some = paper describing why it occurs and perhaps even strategies for solving = the problem (most likely patented ones) Jake > -----Original Message----- > From: gda...@li... > [mailto:gda...@li...]On=20 > Behalf Of Madoc > Evans > Sent: 25 March 2004 13:26 > To: gda...@li... > Subject: [Algorithms] vrefresh jumpiness >=20 >=20 >=20 > I've noticed that whenever framerates drop below the monitor=20 > refresh rate > renderings look they're jumping back and forth, it basically=20 > looks like > there are more offset images overlayed. The problem is most=20 > noticeable with > vsync enabled. This problem is visible in all programs and=20 > hardware I've > seen and it's _really ugly_. I'm puzzled that I've never seen=20 > it mentioned. > I might even have thought that it's some optical illusion=20 > that I only am > subject to if it weren't that all my collegues agree that it's very > disturbing (something in the air at the office?). >=20 > Anyway, I can't quite understand why it looks as bad as it=20 > does. I guess > It's just to do with the way we perceive the monitor's=20 > flickering image and > there's just nothing to do about it, I can't seem to improve=20 > it. Has anyoene > ever tried to correct it with any success? Am I missing some=20 > really obvious > reason why it can't be? >=20 > Cheers, > Madoc >=20 >=20 >=20 >=20 > ------------------------------------------------------- > This SF.Net email is sponsored by: IBM Linux Tutorials > Free Linux tutorial presented by Daniel Robbins, President and CEO of > GenToo technologies. Learn everything from fundamentals to system > = administration.http://ads.osdn.com/?ad_id=3D1470&alloc_id=3D3638&op=3Dcli= ck > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=3D6188 >=20 |
From: Bretton W. <bre...@mi...> - 2004-03-30 22:31:37
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Is the frame rate an even divisor of the monitor refresh rate? If so, then the aliasing artifact that everybody is talking about is probably close to correct. The other possibility is that the frame is not getting updated on some regular multiple of the monitor refresh rate. If that's the case, then the problem you are seeing is an artifact of irregular sampling that should be corrected by carefully regulating your frame time. The reason it's not showing up with v-blank turned off is that you are getting multiple-frame tearing instead. My general advice on this point is to correlate the game update rate to your monitor refresh rate if you can (though that can be the wrong thing to do in a multi-player environment). Whatever you do, don't use the system time from one frame to the next as your physics clock. -- Bretton Wade (aka Noz Moe King) in Bellevue, WA > > -----Original Message----- > > From: gda...@li... > > [mailto:gda...@li...]On > > Behalf Of Madoc > > Evans > > Sent: 25 March 2004 13:26 > > To: gda...@li... > > Subject: [Algorithms] vrefresh jumpiness > > > > > > > > I've noticed that whenever framerates drop below the monitor > > refresh rate > > renderings look they're jumping back and forth, it basically > > looks like > > there are more offset images overlayed. The problem is most > > noticeable with > > vsync enabled. This problem is visible in all programs and > > hardware I've > > seen and it's _really ugly_. I'm puzzled that I've never seen > > it mentioned. > > I might even have thought that it's some optical illusion > > that I only am > > subject to if it weren't that all my collegues agree that it's very > > disturbing (something in the air at the office?). > > > > Anyway, I can't quite understand why it looks as bad as it > > does. I guess > > It's just to do with the way we perceive the monitor's > > flickering image and > > there's just nothing to do about it, I can't seem to improve > > it. Has anyoene > > ever tried to correct it with any success? Am I missing some > > really obvious > > reason why it can't be? > > > > Cheers, > > Madoc |
From: Dan T. <da...@ar...> - 2004-03-31 22:06:37
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Fascinating talks about vision and such. I may need to move this to a new thread, but what's this about using the monitor rate for physics and not the system time? I don't remember anything about monitor rates in the timing threads that have gone through here. I just use the game time(QueryPerf or timeGetTime or whathaveyou.) and run the physics at a constant 30fps based on that. Its running OK to handle the baraff solver for the constraint stuff so far. Did I just misunderstand you? If its painfully obvious and I'm just off in la la land, reply offline please... -Dan ----- Original Message ----- From: "Bretton Wade" <bre...@mi...> To: <gda...@li...> Sent: Tuesday, March 30, 2004 2:31 PM Subject: [email] RE: [Algorithms] vrefresh jumpiness Is the frame rate an even divisor of the monitor refresh rate? If so, then the aliasing artifact that everybody is talking about is probably close to correct. The other possibility is that the frame is not getting updated on some regular multiple of the monitor refresh rate. If that's the case, then the problem you are seeing is an artifact of irregular sampling that should be corrected by carefully regulating your frame time. The reason it's not showing up with v-blank turned off is that you are getting multiple-frame tearing instead. My general advice on this point is to correlate the game update rate to your monitor refresh rate if you can (though that can be the wrong thing to do in a multi-player environment). Whatever you do, don't use the system time from one frame to the next as your physics clock. -- Bretton Wade (aka Noz Moe King) in Bellevue, WA > > -----Original Message----- > > From: gda...@li... > > [mailto:gda...@li...]On > > Behalf Of Madoc > > Evans > > Sent: 25 March 2004 13:26 > > To: gda...@li... > > Subject: [Algorithms] vrefresh jumpiness > > > > > > > > I've noticed that whenever framerates drop below the monitor > > refresh rate > > renderings look they're jumping back and forth, it basically > > looks like > > there are more offset images overlayed. The problem is most > > noticeable with > > vsync enabled. This problem is visible in all programs and > > hardware I've > > seen and it's _really ugly_. I'm puzzled that I've never seen > > it mentioned. > > I might even have thought that it's some optical illusion > > that I only am > > subject to if it weren't that all my collegues agree that it's very > > disturbing (something in the air at the office?). > > > > Anyway, I can't quite understand why it looks as bad as it > > does. I guess > > It's just to do with the way we perceive the monitor's > > flickering image and > > there's just nothing to do about it, I can't seem to improve > > it. Has anyoene > > ever tried to correct it with any success? Am I missing some > > really obvious > > reason why it can't be? > > > > Cheers, > > Madoc ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id70&alloc_id638&op=ick _______________________________________________ GDAlgorithms-list mailing list GDA...@li... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 |
From: Lorenzo P. <pas...@ul...> - 2004-03-30 08:03:25
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What you see is a form of aliasing, taking place at a mutch higher level than texel. If you reduce the problem to frequencies addition you get a very common artefact : pull the other frequency out of tune/enharmonic and you'll get a lower frequency added, pull it out of phase you'll lose some of your signal. This not a perceptual thang, Fourier can tell you. I might be wrong but, I guess that there is no strategy that won't assume to _get in sync_ with some common referent in the first place. My 2 cents Lo. ----- Original Message ----- From: "Jacob Turner (Core Design Ltd)" <JacobT@Core-Design.com> To: <gda...@li...> Sent: Thursday, March 25, 2004 5:16 PM Subject: RE: [Algorithms] vrefresh jumpiness I believe this is called "multiple imaging". If your update rate doesn't match the refresh rate then your brain is expecting the gaps between the update frames but because they aren't there the brain gets a bit confused and you see multiple images. If you search for multiple-image suppression and look around at the evans and sutherland site you should find some paper describing why it occurs and perhaps even strategies for solving the problem (most likely patented ones) Jake > -----Original Message----- > From: gda...@li... > [mailto:gda...@li...]On > Behalf Of Madoc > Evans > Sent: 25 March 2004 13:26 > To: gda...@li... > Subject: [Algorithms] vrefresh jumpiness > > > > I've noticed that whenever framerates drop below the monitor > refresh rate > renderings look they're jumping back and forth, it basically > looks like > there are more offset images overlayed. The problem is most > noticeable with > vsync enabled. This problem is visible in all programs and > hardware I've > seen and it's _really ugly_. I'm puzzled that I've never seen > it mentioned. > I might even have thought that it's some optical illusion > that I only am > subject to if it weren't that all my collegues agree that it's very > disturbing (something in the air at the office?). > > Anyway, I can't quite understand why it looks as bad as it > does. I guess > It's just to do with the way we perceive the monitor's > flickering image and > there's just nothing to do about it, I can't seem to improve > it. Has anyoene > ever tried to correct it with any success? Am I missing some > really obvious > reason why it can't be? > > Cheers, > Madoc > > > > > ------------------------------------------------------- > This SF.Net email is sponsored by: IBM Linux Tutorials > Free Linux tutorial presented by Daniel Robbins, President and CEO of > GenToo technologies. Learn everything from fundamentals to system > administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 > ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id70&alloc_id638&op=ick _______________________________________________ GDAlgorithms-list mailing list GDA...@li... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 |