Thread: RE: [Algorithms] FPS Questions
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From: Steve W. <Ste...@im...> - 2000-07-31 16:54:41
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Personally, I use a counter for the number of frames I render, plus use a timer at 1 second intervals to display the count and reset it for the next second. I don't have any game code yet...just the collision testing and 10,000 tris with one point light and ability to 'fly' around the world which consists of a sphere, a triangular pyramid, and two square boxes. I get 70 fps at 640x480x32 running a PII-350 with Creative Labs Rive TNT AGP, but drops down to 55 when the objects completely fill the screen. R&R > -----Original Message----- > From: Pai-Hung Chen [mailto:pa...@ac...] > Sent: Sunday, July 30, 2000 3:18 PM > To: GDA...@li... > Subject: [Algorithms] FPS Questions > > > Hi, > > (1) Is there a universally agreed way to calculate > Frame-Per-Second information? > > (2) What is the acceptable FPS for today's 3D games? > > Thanks, > > Pai-Hung Chen > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: Steve W. <Ste...@im...> - 2000-07-31 16:57:36
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OOPS! I meant 1,000 tris. Personally, I use a counter for the number of frames I render, plus use a timer at 1 second intervals to display the count and reset it for the next second. I don't have any game code yet...just the collision testing and 10,000 tris with one point light and ability to 'fly' around the world which consists of a sphere, a triangular pyramid, and two square boxes. I get 70 fps at 640x480x32 running a PII-350 with Creative Labs Rive TNT AGP, but drops down to 55 when the objects completely fill the screen. R&R > -----Original Message----- > From: Pai-Hung Chen [mailto:pa...@ac...] > Sent: Sunday, July 30, 2000 3:18 PM > To: GDA...@li... > Subject: [Algorithms] FPS Questions > > > Hi, > > (1) Is there a universally agreed way to calculate > Frame-Per-Second information? > > (2) What is the acceptable FPS for today's 3D games? > > Thanks, > > Pai-Hung Chen > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > -----Original Message----- > From: Pai-Hung Chen [mailto:pa...@ac...] > Sent: Sunday, July 30, 2000 3:18 PM > To: GDA...@li... > Subject: [Algorithms] FPS Questions > > > Hi, > > (1) Is there a universally agreed way to calculate > Frame-Per-Second information? > > (2) What is the acceptable FPS for today's 3D games? > > Thanks, > > Pai-Hung Chen > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: <sro...@te...> - 2000-07-31 20:03:31
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well, i dont know for you but i can see the difference beetween 30 and 60 fps Corrosif, Ignore demands from the marketing department to release premature shots. These people are for the most part clueless, and are only trying to justify their job." George Broussard, President of 3DRealms. -----Original Message----- From: gda...@li... [mailto:gda...@li...]On Behalf Of Jim Offerman Sent: Monday, July 31, 2000 3:31 PM To: gda...@li... Subject: Re: [Algorithms] FPS Questions > 60fps is the ideal target. I blindly follow the masses here, but I can't help wondering why... Anything above 24-25 fps will not be noticed by the human eye, 30 fps animations look _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we rather crank up the detail some more and all target 30 fps? What makes a 60 fps game more playable than a 30 fps game? Jim Offerman Innovade - designing the designer _______________________________________________ GDAlgorithms-list mailing list GDA...@li... http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list |
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From: gl <gl...@nt...> - 2000-07-31 20:18:32
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Not only can I see the difference between 30 and 60 (they're a world apart), I also find < 85Hz monitor refresh rate tiring. At a 100, something very interesting happens that's hard to put into words. As with all things, once you exceed the obvious limitations of something you find that there is still a world of sublety to explore, so don't write off >60 fps just yet (Quake2 for example is especially 'liquid' at 100+). The reason this comes up time and time again is precisely because I think many people really can't tell the difference. However, those'll just have to accept that many of us can. -- gl ----- Original Message ----- From: <sro...@te...> To: <gda...@li...> Sent: Monday, July 31, 2000 9:05 PM Subject: RE: [Algorithms] FPS Questions > well, i dont know for you but i can see the difference beetween 30 and 60 > fps > > Corrosif, > Ignore demands from the marketing department to release premature shots. > These people are for the most part clueless, and are only trying to justify > their job." George Broussard, President of 3DRealms. > > > -----Original Message----- > From: gda...@li... > [mailto:gda...@li...]On Behalf Of Jim > Offerman > Sent: Monday, July 31, 2000 3:31 PM > To: gda...@li... > Subject: Re: [Algorithms] FPS Questions > > > > 60fps is the ideal target. > > I blindly follow the masses here, but I can't help wondering why... Anything > above 24-25 fps will not be noticed by the human eye, 30 fps animations look > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > rather crank up the detail some more and all target 30 fps? What makes a 60 > fps game more playable than a 30 fps game? > > Jim Offerman > > Innovade > - designing the designer > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: Keith Z.L. <ke...@dr...> - 2000-07-31 20:22:32
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All good points brought up. On average (the average 3D game), you want to shoot for 60 fps. But there are 3D games that don't require that level of performance, for instance an adventure game, or turn based stradegy game, or 3D solitare. :-) And 60 fields per second on TV is better than 30 any day. Keith gl wrote: > Not only can I see the difference between 30 and 60 (they're a world apart), > I also find < 85Hz monitor refresh rate tiring. At a 100, something very > interesting happens that's hard to put into words. As with all things, once > you exceed the obvious limitations of something you find that there is still > a world of sublety to explore, so don't write off >60 fps just yet (Quake2 > for example is especially 'liquid' at 100+). > > The reason this comes up time and time again is precisely because I think > many people really can't tell the difference. However, those'll just have > to accept that many of us can. > -- > gl > > ----- Original Message ----- > From: <sro...@te...> > To: <gda...@li...> > Sent: Monday, July 31, 2000 9:05 PM > Subject: RE: [Algorithms] FPS Questions > > > well, i dont know for you but i can see the difference beetween 30 and 60 > > fps > > > > Corrosif, > > Ignore demands from the marketing department to release premature shots. > > These people are for the most part clueless, and are only trying to > justify > > their job." George Broussard, President of 3DRealms. > > > > > > -----Original Message----- > > From: gda...@li... > > [mailto:gda...@li...]On Behalf Of Jim > > Offerman > > Sent: Monday, July 31, 2000 3:31 PM > > To: gda...@li... > > Subject: Re: [Algorithms] FPS Questions > > > > > > > 60fps is the ideal target. > > > > I blindly follow the masses here, but I can't help wondering why... > Anything > > above 24-25 fps will not be noticed by the human eye, 30 fps animations > look > > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > > rather crank up the detail some more and all target 30 fps? What makes a > 60 > > fps game more playable than a 30 fps game? > > > > Jim Offerman > > > > Innovade > > - designing the designer > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list |
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From: Keith Z.L. <ke...@dr...> - 2000-07-31 20:31:14
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also for me, I like it 60 fps at 1024x768x32. That's just my pet resolution. though 640x480x32@60hz anti-aliased is good too. :-) Keith "Keith Z.Leonard" wrote: > All good points brought up. > > On average (the average 3D game), you want to shoot for 60 fps. > But there are 3D games that don't require that level of performance, > for instance an adventure game, or turn based stradegy game, or > 3D solitare. :-) > > And 60 fields per second on TV is better than 30 any day. > > Keith > > gl wrote: > > > Not only can I see the difference between 30 and 60 (they're a world apart), > > I also find < 85Hz monitor refresh rate tiring. At a 100, something very > > interesting happens that's hard to put into words. As with all things, once > > you exceed the obvious limitations of something you find that there is still > > a world of sublety to explore, so don't write off >60 fps just yet (Quake2 > > for example is especially 'liquid' at 100+). > > > > The reason this comes up time and time again is precisely because I think > > many people really can't tell the difference. However, those'll just have > > to accept that many of us can. > > -- > > gl > > > > ----- Original Message ----- > > From: <sro...@te...> > > To: <gda...@li...> > > Sent: Monday, July 31, 2000 9:05 PM > > Subject: RE: [Algorithms] FPS Questions > > > > > well, i dont know for you but i can see the difference beetween 30 and 60 > > > fps > > > > > > Corrosif, > > > Ignore demands from the marketing department to release premature shots. > > > These people are for the most part clueless, and are only trying to > > justify > > > their job." George Broussard, President of 3DRealms. > > > > > > > > > -----Original Message----- > > > From: gda...@li... > > > [mailto:gda...@li...]On Behalf Of Jim > > > Offerman > > > Sent: Monday, July 31, 2000 3:31 PM > > > To: gda...@li... > > > Subject: Re: [Algorithms] FPS Questions > > > > > > > > > > 60fps is the ideal target. > > > > > > I blindly follow the masses here, but I can't help wondering why... > > Anything > > > above 24-25 fps will not be noticed by the human eye, 30 fps animations > > look > > > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > > > rather crank up the detail some more and all target 30 fps? What makes a > > 60 > > > fps game more playable than a 30 fps game? > > > > > > Jim Offerman > > > > > > Innovade > > > - designing the designer > > > > > > > > > _______________________________________________ > > > GDAlgorithms-list mailing list > > > GDA...@li... > > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > > > > > > _______________________________________________ > > > GDAlgorithms-list mailing list > > > GDA...@li... > > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list |
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From: Tom F. <to...@mu...> - 2000-07-31 20:05:59
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Lower latency - that's what FPS players from higher fps (excuse the pun). They also say that you can spin faster and not have any gaps in your visual coverage of a room. I'll have to trust them on that - I have no problems scanning a room quickly on my fairly average setup, which is probably going at around 25-30Hz. If you spin too fast, your optical shutters kick in (I used to know what they were called - anyone? - they stop you getting confused by rapid head movements). But I'm sure 99% of the effect is just lower latency. Tom Forsyth - Muckyfoot bloke. Whizzing and pasting and pooting through the day. > -----Original Message----- > From: Jim Offerman [mailto:j.o...@in...] > Sent: 31 July 2000 20:31 > To: gda...@li... > Subject: Re: [Algorithms] FPS Questions > > > > 60fps is the ideal target. > > I blindly follow the masses here, but I can't help wondering > why... Anything > above 24-25 fps will not be noticed by the human eye, 30 fps > animations look > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > rather crank up the detail some more and all target 30 fps? > What makes a 60 > fps game more playable than a 30 fps game? > > Jim Offerman > > Innovade > - designing the designer > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: gl <gl...@nt...> - 2000-07-31 20:21:02
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Not so. The 'liquidity' (for want of a better term) from the high fps is really quite startling - if you can see it that is. As I said, I think a lot of people can't, so they are very eager to disbelieve anyone that can. Most FPS gamers I know can tell the difference. -- gl ----- Original Message ----- From: "Tom Forsyth" <to...@mu...> To: <gda...@li...> Sent: Monday, July 31, 2000 9:01 PM Subject: RE: [Algorithms] FPS Questions > Lower latency - that's what FPS players from higher fps (excuse the pun). > They also say that you can spin faster and not have any gaps in your visual > coverage of a room. I'll have to trust them on that - I have no problems > scanning a room quickly on my fairly average setup, which is probably going > at around 25-30Hz. If you spin too fast, your optical shutters kick in (I > used to know what they were called - anyone? - they stop you getting > confused by rapid head movements). > > But I'm sure 99% of the effect is just lower latency. > > Tom Forsyth - Muckyfoot bloke. > Whizzing and pasting and pooting through the day. > > > -----Original Message----- > > From: Jim Offerman [mailto:j.o...@in...] > > Sent: 31 July 2000 20:31 > > To: gda...@li... > > Subject: Re: [Algorithms] FPS Questions > > > > > > > 60fps is the ideal target. > > > > I blindly follow the masses here, but I can't help wondering > > why... Anything > > above 24-25 fps will not be noticed by the human eye, 30 fps > > animations look > > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > > rather crank up the detail some more and all target 30 fps? > > What makes a 60 > > fps game more playable than a 30 fps game? > > > > Jim Offerman > > > > Innovade > > - designing the designer > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: Doug C. <dc...@d-...> - 2000-07-31 21:14:59
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Well Im am what you might call a big quake player and the extra FPS really helps when trying to dodge projectiles and predict where to aim projectiles. Its hard to explain why it helps exactly but there is something about the visual fluidity and natural human aiming instincts I suspect. Thats probably why most quake players use USB mice for their smoother mouse response. Most of the quake players I know ( at work and on the net ) like to get at least 100fps and many like 120 or above. They turn all their settings down *really* low so quake3 looks worse than quake1 to achieve this rate. Im lucky since I have a fast machine with a GF2 board which allows me to pretty much leave it cranked and still get over 100fps. I dont think 100fps is a reasonable requirement for most games, especially single player ones - I think that for a single player FPS, racing game or 3PS, 30fps is adequate for fun gameplay, but 60 is always worth shooting for. Doug Chism ----- Original Message ----- From: "Tom Forsyth" <to...@mu...> To: <gda...@li...> Sent: Monday, July 31, 2000 4:01 PM Subject: RE: [Algorithms] FPS Questions > Lower latency - that's what FPS players from higher fps (excuse the pun). > They also say that you can spin faster and not have any gaps in your visual > coverage of a room. I'll have to trust them on that - I have no problems > scanning a room quickly on my fairly average setup, which is probably going > at around 25-30Hz. If you spin too fast, your optical shutters kick in (I > used to know what they were called - anyone? - they stop you getting > confused by rapid head movements). > > But I'm sure 99% of the effect is just lower latency. > > Tom Forsyth - Muckyfoot bloke. > Whizzing and pasting and pooting through the day. > > > -----Original Message----- > > From: Jim Offerman [mailto:j.o...@in...] > > Sent: 31 July 2000 20:31 > > To: gda...@li... > > Subject: Re: [Algorithms] FPS Questions > > > > > > > 60fps is the ideal target. > > > > I blindly follow the masses here, but I can't help wondering > > why... Anything > > above 24-25 fps will not be noticed by the human eye, 30 fps > > animations look > > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > > rather crank up the detail some more and all target 30 fps? > > What makes a 60 > > fps game more playable than a 30 fps game? > > > > Jim Offerman > > > > Innovade > > - designing the designer > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: Chris S. <th...@xn...> - 2000-07-31 22:36:24
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Multiplayer racing games, especially simulations, actually are very much like multiplayer FPS games for most of the same reasons, but also more importantly that the physics are usually updated at a higher rate than in most FPS games. Its been proven in Grand Prix Legends (by Papyrus) online competition that you MUST have 36fps (the max. framerate in GPL) or you are at a serious disadvantage. Most folks in the GPL community would perfer more fps than 36, so I'd say 60 is a definete target, if the the software would allow for it. GPL isn't the only racing simulation that this effect has been noticed in; TEN's NROS also experienced this. > Most of the quake players I know ( at work and on the net ) like to get at > least 100fps and many like 120 or above. They turn all their settings down > *really* low so quake3 looks worse than quake1 to achieve this rate. Im > lucky since I have a fast machine with a GF2 board which allows me to pretty > much leave it cranked and still get over 100fps. I dont think 100fps is a > reasonable requirement for most games, especially single player ones - I > think that for a single player FPS, racing game or 3PS, 30fps is adequate > for fun gameplay, but 60 is always worth shooting for. |
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From: Stephen J B. <sj...@li...> - 2000-08-01 16:41:39
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On Mon, 31 Jul 2000, Tom Forsyth wrote: > Lower latency - that's what FPS players from higher fps (excuse the pun). > They also say that you can spin faster and not have any gaps in your visual > coverage of a room. I'll have to trust them on that - I have no problems > scanning a room quickly on my fairly average setup, which is probably going > at around 25-30Hz. If you spin too fast, your optical shutters kick in (I > used to know what they were called - anyone? Saccade. > - they stop you getting confused by rapid head movements). But I don't think that spinning the graphics around fast will induce a saccade - your eyes have to move to make that happen. Steve Baker (817)619-2657 (Vox/Vox-Mail) L3Com/Link Simulation & Training (817)619-2466 (Fax) Work: sj...@li... http://www.link.com Home: sjb...@ai... http://web2.airmail.net/sjbaker1 |
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From: Steve W. <Ste...@im...> - 2000-07-31 20:27:53
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> -----Original Message----- > From: Jim Offerman [mailto:j.o...@in...] > > > 60fps is the ideal target. > > I blindly follow the masses here, but I can't help wondering > why... Anything > above 24-25 fps will not be noticed by the human eye, 30 fps > animations look > _really_ smooth. So why are we all targetting for 60 fps? Shouldn't we > rather crank up the detail some more and all target 30 fps? > What makes a 60 > fps game more playable than a 30 fps game? > I think the ideal target fps needs to detailed further since fps is relative to the bits per pixel and window or screen size. I'm assuming that Keith's ideal 60fps is at 640x480x32 fullscreen...so that someone can play it at 800x600x32 and get about 30fps, or 1024x768 and get the 24-25fps. R&R |
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From: jason w. <jas...@po...> - 2000-07-31 21:10:57
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the sort answer: yes, anothing above 24fps will, due to persistance of vision, have the appearence of being continous, not flashing frames. this does _not_ mean the human eye is unable to tell the difference between 30 and 60 fps. longer answer: the vast majority of games will set their systems and settings such that they get around 60fps.. whatever resolution this requires.. another interesting bit.. people with Geforce2 GTS's could run at 1600x1200 and get ~60fps in many games.. but they don't... they almost always like 1280x1024 and the ~100fps better. personally, I even perfer getting above 85 hz, which is what my monitor refresh typically runs at. there's also the isssue of aliasing if you're syncing to vsync. When you're running say 72hz refresh.. if you don't have every frame ready in time, then that frame has to wait an entire refresh. suddenly you've dropped a frame.. if you're in the middle of an intense fire fight, it's concievable that you may even go past 2 72hz periods, drop 2 frames, and end up with 18hz for a frame or 2. let me tell you, consistance is a wonderful thing.. I would *definately* like it better if q3a degraded some of the effects as nessisary to keep from dropping frames. another thing I've noticed in counterstrike.. in counterstrike, there's lag compensation.. effectively this means that if you have your crosshair on the image of the enemy on your screen, and click fire, then you'll hit. This is unlike other games, where you have to lead some small or large amount to compensate for network lag. So, usually my goal in each frame is to get my crosshair on target by the next frame or 2.. when my display is rendering at 80fps, this is easy.. the motions are so smooth... at 30fps, it's much harder.. I'm quite sure that at 80fps, my brain is getting more information. there is really no framerate to the human eye.. everything is fuzzy.. so don't count on arbitrary rules like "24 fps".. instead, test it, see how if feels, see what people say. give gamer the choice. this reminds me a lot of the audio world.. people commonly believe human hearing extends between 20hz and 20khz.. while this is roughly true when using a spectrum analysys model of the human ear, it's not true when using an impulse or other model. |
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From: Stephen J B. <sj...@li...> - 2000-08-01 16:48:24
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On Mon, 31 Jul 2000, jason watkins wrote: > there's also the isssue of aliasing if you're syncing to vsync. When you're > running say 72hz refresh.. if you don't have every frame ready in time, then > that frame has to wait an entire refresh. suddenly you've dropped a frame.. > if you're in the middle of an intense fire fight, it's concievable that you > may even go past 2 72hz periods, drop 2 frames, and end up with 18hz for a > frame or 2. Not 18, it would be 24Hz. Steve Baker (817)619-2657 (Vox/Vox-Mail) L3Com/Link Simulation & Training (817)619-2466 (Fax) Work: sj...@li... http://www.link.com Home: sjb...@ai... http://web2.airmail.net/sjbaker1 |
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From: Graham S. R. <gr...@se...> - 2000-07-31 22:03:30
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I like Jason's post. It is fairly consistent with my own observations, which I describe here. He may not agree with my whole discussion, though. The old "fact" that 25-30 fps is enough for animation that appears continuous to the human eye was discovered when viewing movies of fairly slow moving objects. Slow compared to FPS games during attack sequences, for example. It just happens that 60 fps or 100 fps or 25 or 30 fps just works out nicely for most current games. Does anyone have any reference that states that the human eye *cannot* resolve *much* better than, say, 100 fps? I would bet that it *can*. My monitor is running at a refresh rate of 75Hz now. Not 100Hz, but close enough. If I just move a pencil across the screen at at speed that is consistent with the speed of some computer game actors, I see the distinct strobe effect that indicates when the screen is refreshing. I have to slow the pencil down significantly before it appears to move smoothly with no strobing. (This seems move obvious when you move the pencil diagonally across the screen. Also, you when the pencil is moving slowly, you will detect the strobing more effectively in your peripheral vision----so keep your eyes focused at one point while moving the pencil.) We can think about this without getting too theoretical, in my view. It seems to me that the target frame rate will generally be a function of how fast the fastest actor/game element is moving on the screen, in, say, pixels per second. Count how fast the thing or character is moving in pixels per second, and the number of pixels is the number of frames you need to get the SMOOTHEST possible animation. Think about the pencil example. When I slow the pencil down, I am really reducing its speed, in pixels/second, down so that it moves roughly one pixel per frame. That gives the smoothest possible motion of the pencil, given the strobing screen behind. For example, if a bot is moving at 250 pixels per second (roughly 4 seconds to cross a 1024 pixel screen), then you need 250 frames per second to represent the position of that bot at every pixel location it would potentially occupy in a second. If its moving 60 pixels/second then you need 60 fps. 25 pixels/sec needs 25 fps, etc. Imagine a very fast moving element in a game, one that moves across the entire screen in one second---this doesn't seem too fast if you think about it. If you just move that pencil across in one second it looks fairly slow. To get the smoothest possible animation (in terms of pixel jumping), you would need to have a frame rate equal to the pixel resolution of the screen. For a 1024 pixel screen, you'd want 1024 fps. At some point, pixels are very small and we can think about something other than pixels/second. Perhaps tens of pixels per second is close to ideal----this would be consistent with the current trend of looking for 100fps. (At some point, we may need to look at the ability of the eye to resolve individual pixels, and the angular displacement of objects relative to the eye----these being functions of distance from the screen...) So, in summary, I believe the target frame rate should be a function of the rate of movement in screen space of the fastest moving game element. Some games will continue to need 25-30, some 60, some 100, and, perhaps, 300fps will be best for some games. Beyond monitor synchronization and frame drop issues, there will probably be a *requirement* for motion blur and some other kinds of temporal antialiasing if we get too fast, I suppose. Can we even make a monitor that runs at extraordinary refresh rates? What happens in 5 years when we all have monitors running at 2000 pixels horizontally? Large immersive displays such as CAVE's already run at 96 frames per second at that resolution... What happens when we are all using stereoscopic hardware all the time, so that each eye sees have the total frame rate. 100fps becomes 50fps. We will then need 200fps to match today's 100fps..... Food for thought. Graham Rhodes |
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From: gl <gl...@nt...> - 2000-07-31 22:30:49
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> The old "fact" that 25-30 fps is enough for animation that appears > continuous to the human eye was discovered when viewing movies of fairly > slow moving objects. Also, consider motion blur. Without being too technically accurate about how cameras work, lets simplify and state that a camera is actually recording all the information available. Whilst it does chop up the 'real stream' into (eg.) 24 fps, during each interval it is capturing the remaining information by allowing light into its sensor (film etc) for the full timeslice, resulting in motion blur. ie. motion blur actually represents all the 'missing' information in slow fps media. That's why without it, computer graphics need a much higher fps to get a similar feeling of smoothness. -- gl |
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From: Graham S. R. <gr...@se...> - 2000-08-01 14:33:37
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> Also, consider motion blur. Without being too technically accurate about > how cameras work, lets simplify and state that a camera is actually > recording all the information available. Whilst it does chop up the 'real > stream' into (eg.) 24 fps, during each interval it is capturing the > remaining information by allowing light into its sensor (film etc) for the > full timeslice, resulting in motion blur. > > ie. motion blur actually represents all the 'missing' information in slow > fps media. That's why without it, computer graphics need a much > higher fps to get a similar feeling of smoothness. > -- > gl Yes, that's right. There is information in a real camera frame beyond just 24 fps of geometry positions that helps the eye extrapolate more detail. Such subtlety. Perhaps we can do with 60-100fps, but with at *least* 10 samples into an accumulation or T-buffer to get a nice, smooth (unbanded) motion blur effect. If we're actually redrawing entire scenes to get those 10 motion-blur samples (e.g., objects *and* the camera are moving), then we're once again up to sort of needing 500-1000 fps drawing rate. At least we can avoid the issue of monitors not being able to do huge, huge refresh rates. A bit easier to achieve if only a few small objects are moving, and the camera is not moving. Graham Rhodes |
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From: Stephen J B. <sj...@li...> - 2000-08-01 17:33:40
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On Mon, 31 Jul 2000, Graham S. Rhodes wrote:
> I like Jason's post. It is fairly consistent with my own observations, which
> I describe here. He may not agree with my whole discussion, though.
This stuff is well researched and understood.
Flight simulator people have been aware of the issue for 20 years.
> The old "fact" that 25-30 fps is enough for animation that appears
> continuous to the human eye was discovered when viewing movies of fairly
> slow moving objects. Slow compared to FPS games during attack sequences, for
> example. It just happens that 60 fps or 100 fps or 25 or 30 fps just works
> out nicely for most current games.
There is also a BIG difference between 24Hz movies and (say) 30Hz video.
In a 24Hz movie, each image is only drawn once - so there are 24 separate
still frames.
<apologies to people who've heard me explain this many times before>
In a 30Hz video animation on a 60Hz CRT, each image is drawn TWICE by
the CRT - so there are 60 separate still frames - with two consecutive
identical images being painted onto the phosphor between each swapbuffer
call.
That distinction might not seem to matter - so you'd expect 30Hz graphics
to look better than 24Hz movies - however, they don't - and here is why:
Our brains evolved for tasks like watching a small furry animal running
around in a forest - then letting us throw a rock at it and stand a good
chance of hitting it.
That means that when the cute bunny runs along and tree trunks, bushes,
etc get between it and us, we have to mentally interpolate it's position
in order to fill in the gaps in the imagery coming from our eyes. If
your brain didn't do that, you'd think that you were seeing a set of
separate disconnected events - and throwing a rock would be impossible.
That hardwired interpolation is what screws up our perception of 30Hz
animation on 60Hz video.
Look at a graph of position against time for an object moving
at a constant speed - displayed using 30Hz graphics on a 60Hz video
screen:
|
| . .
^ | . .
| | . .
posn | . .
| . .
| . .
| . .
|____________________________
time ->
Linear motion - but two consecutive images at each position - right?
Well, when your brain tries to interpolate between those still
images, it tries to make a straight line through the points,
but it can't - it's a stair-step function.
However, one way to view this graph is as TWO parallel straight
lines. You can easily draw two parallel lines through those
points - and they fit the data perfectly.
That's what your brain does. So you don't see ONE object moving
jerkily - you see TWO objects moving smoothly but flickering
at 30Hz. This means that all fast moving objects double-image
at 30Hz - and they flicker too.
When the graphics are only updated at 20Hz, you get triple-imaging,
as you'd expect. But there comes a point at poor enough frame rates
at which your brain accepts that this is jerky motion and not
multiple moving objects.
For me, that sometimes happens at 20Hz and sometimes at 15. It seems
to depend on the ambient lighting. Somewhere around that speed, I can
sometimes 'flip' my brain between seeing multiple images and jerkiness
by concentrating on that - just like you can make some optical illusions
flip between two states by staring hard at them.
Different people hit this effect at different speeds. One of my co-workers
can see quadruple-images at 15Hz - I've never seen that.
In a movie theater, each image is only painted once - so a perfect
straight line can be drawn through the points and no double-imaging
is aparrent - although the flicker is bad and the heavy motion blur
can get ugly.
> Does anyone have any reference that states that the human eye *cannot*
> resolve *much* better than, say, 100 fps?
No - to the contrary. There are people who can resolve much better than
100Hz. If you run a CRT at 120Hz but update the graphics at 60, the
double imaging comes back. That proves that your eyes are still seeing
a non-continuous image - even if your higher cognitive centers don't
notice it. It would be interesting to do that with 200Hz video and 100Hz
rendering - but I don't have a CRT that'll go that fast.
I suspect the limit would be the persistance of the phosphor rather than
a limitation of the eye/brain. All those neurons are firing asynchronously
so there will always be some that see the interruption to the light.
The idea that the eye/brain somehow doesn't see the black periods between
the redraws at over 20Hz is a fallacy. What happens is that the
interrupted image is reconstructed into smooth interpolated motion for
your higher level cognitive functions...but when (redraw rate != video
rate) your mental interpolator gets confused because it evolved to
throw rocks at rabbits running behind trees.
Obviously humanity may sometime evolve to be able to interpolate 30Hz
images - but that presumes that people who play a lot of video games
successfully will be more likely to pass on their genes to the next
generation. The reality is probably the opposite of that! :-)
> What happens in 5 years when we all have monitors running at 2000 pixels
> horizontally? Large immersive displays such as CAVE's already run at 96
> frames per second at that resolution... What happens when we are all using
> stereoscopic hardware all the time, so that each eye sees have the total
> frame rate. 100fps becomes 50fps. We will then need 200fps to match today's
> 100fps..... Food for thought.
No - that's not true. We've run 3500x2200 pixel screens and 60Hz still looks
just as good as it does on a 1000 pixel screen.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
L3Com/Link Simulation & Training (817)619-2466 (Fax)
Work: sj...@li... http://www.link.com
Home: sjb...@ai... http://web2.airmail.net/sjbaker1
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From: Jim O. <j.o...@in...> - 2000-08-01 18:38:57
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> In a movie theater, each image is only painted once - so a perfect > straight line can be drawn through the points and no double-imaging > is aparrent - although the flicker is bad and the heavy motion blur > can get ugly. I tried, but I just can't resist.... We have established earlier that a cinema projector displays every image twice, to effectively realize 48 fps. Essentially, you would be experiencing the same phenomena in there, right? Jim Offerman Innovade - designing the designer |
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From: Graham S. R. <gr...@se...> - 2000-08-01 18:46:07
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Steve Baker wrote, > -----Original Message----- > I suspect the limit would be the persistance of the phosphor rather than > a limitation of the eye/brain. All those neurons are firing asynchronously > so there will always be some that see the interruption to the light. Its interesting that you mention persistence of the phosphor. We see an artifact when using shutter glasses for stereoscopic viewing that may be due to this effect. On a normal CRT screen, if you close one eye while wearing shutter glasses, you see a shadow of the object, a second image that appears to be the image for the opposite eye. When you are viewing the same scene on a projection display system, the shadow is not there. Since the shadow goes away with the projection system, I feel the shadow must not be leakage through the closed shutter of the open eye. Our theory is that residual light from the previous frame must be the cause. > > [from my previous post - GSR ] > > What happens in 5 years when we all have monitors running at 2000 pixels > > horizontally? Large immersive displays such as CAVE's already run at 96 > > frames per second at that resolution... What happens when we are all using > > stereoscopic hardware all the time, so that each eye sees have the total > > frame rate. 100fps becomes 50fps. We will then need 200fps to match today's > > 100fps..... Food for thought. > > No - that's not true. We've run 3500x2200 pixel screens and 60Hz > still looks just as good as it does on a 1000 pixel screen. Steve, I don't disagree with you here. Sure, 60Hz looks just as good on both screens. But think about stereoscopic mode (which is what I was talking about). At 60hz total, each eye gets 30Hz. Well, that's not quite correct. Each eye gets frames displayed at 60Hz, but rendered frames are delivered at a rate of 30 fps per eye, with 30 frames of blackness in addition. The black frames interlace with rendered frames causing opaque objects to seem transparent. Even at 96 fps (the weird number used by the ImmersaDesk system that we have used on contract to NASA Langley) opaque objects appear a bit transparent in stereo mode. In the office, we try to run 120Hz on CRT's when running in stereo mode. If you want 60Hz *per eye* in stereo mode, then I believe you will need 120Hz total, unless you are using a display such as an HMD that has separate screens for each eye. I was at the IRIS Performer meeting at 1999 SIGGRAPH, and a demonstration was given of the new Hayden planetarium projection display. This has multiple SGI InfiniteReality2 graphics pipes driving seven projector displays with more than 7 million total pixels (see link http://www.trimension-inc.com/company/press_stories.html). As I recall, this is running at only 30fps (it has a database of some 2 billion stars), and it looks just fine. But objects are not moving that fast as the software navigates through the stars. This is not a stereo display, though. The actual display is probably running at 60Hz, and frames are duplicated as you describe in your original post to get 30fps. I wonder if 60fps and stereo mode would look good for this particular software and display system? Graham Rhodes |
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From: gl <gl...@nt...> - 2000-08-01 21:50:40
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> Its interesting that you mention persistence of the phosphor. We see an > artifact when using shutter glasses for stereoscopic viewing that may be due > to this effect. On a normal CRT screen, if you close one eye while wearing > shutter glasses, you see a shadow of the object, a second image that appears > to be the image for the opposite eye. When you are viewing the same scene on > a projection display system, the shadow is not there. Since the shadow goes > away with the projection system, I feel the shadow must not be leakage > through the closed shutter of the open eye. Our theory is that residual > light from the previous frame must be the cause. Yeah, that's a well-known problem with LCD shutters - it is precisely because of the phosphor persistence that you get the ghosting in each eye. Another reason why consumer-based stereoscopic solutions are so disappointing. -- gl (still looking for the Holy Grail in consumer level stereoscopy). |
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From: gl <gl...@nt...> - 2000-08-01 21:45:27
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> your higher level cognitive functions...but when (redraw rate != video > rate) your mental interpolator gets confused because it evolved to > throw rocks at rabbits running behind trees. Are you sure about that? Awful way to spend your time ;) -- gl |
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From: Tom F. <to...@mu...> - 2000-07-31 20:39:29
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Oh yes - on monitor refreshes, 60Hz hurts immediately, <70Hz hurts after a while, and 85Hz is nice. And again, at 100Hz, something rather pleasing happens. But that's a very different effect. Although 60Hz in a game does indeed feel somehow "nicer", it is not (to me) obviously _prettier_ than 30Hz. Certainly, I would much prefer twice as many tris on the screen and running at 30Hz - seeing triangles is much more offensive to my eye than the (perceptually, to me) slightly lower update rate. So I can definately see the difference, I just don't care enough about it to more than halve my poly count. This is another reason that extreme scalability is cool - those that want to play at 20Hz can, and those that want to play at 100Hz can. Incidentally, 24fps panning at the cinema does EVIL things to my eyes - can no-one else see it? It's really really awful and stuttery and blurry and yuk - ruins a good movie. Roll on digital projection.... Tom Forsyth - Muckyfoot bloke. Whizzing and pasting and pooting through the day. > -----Original Message----- > From: gl [mailto:gl...@nt...] > Sent: 31 July 2000 21:18 > To: gda...@li... > Subject: Re: [Algorithms] FPS Questions > > > > Not only can I see the difference between 30 and 60 (they're > a world apart), > I also find < 85Hz monitor refresh rate tiring. At a 100, > something very > interesting happens that's hard to put into words. As with > all things, once > you exceed the obvious limitations of something you find that > there is still > a world of sublety to explore, so don't write off >60 fps > just yet (Quake2 > for example is especially 'liquid' at 100+). > > The reason this comes up time and time again is precisely > because I think > many people really can't tell the difference. However, > those'll just have > to accept that many of us can. > -- > gl > > > ----- Original Message ----- > From: <sro...@te...> > To: <gda...@li...> > Sent: Monday, July 31, 2000 9:05 PM > Subject: RE: [Algorithms] FPS Questions > > > > well, i dont know for you but i can see the difference > beetween 30 and 60 > > fps > > > > Corrosif, > > Ignore demands from the marketing department to release > premature shots. > > These people are for the most part clueless, and are only trying to > justify > > their job." George Broussard, President of 3DRealms. > > > > > > -----Original Message----- > > From: gda...@li... > > [mailto:gda...@li...]On > Behalf Of Jim > > Offerman > > Sent: Monday, July 31, 2000 3:31 PM > > To: gda...@li... > > Subject: Re: [Algorithms] FPS Questions > > > > > > > 60fps is the ideal target. > > > > I blindly follow the masses here, but I can't help wondering why... > Anything > > above 24-25 fps will not be noticed by the human eye, 30 > fps animations > look > > _really_ smooth. So why are we all targetting for 60 fps? > Shouldn't we > > rather crank up the detail some more and all target 30 fps? > What makes a > 60 > > fps game more playable than a 30 fps game? > > > > Jim Offerman > > > > Innovade > > - designing the designer > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > > > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list > |
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From: gl <gl...@nt...> - 2000-07-31 21:04:02
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> Oh yes - on monitor refreshes, 60Hz hurts immediately, <70Hz hurts after a > while, and 85Hz is nice. And again, at 100Hz, something rather pleasing > happens. But that's a very different effect. Yes and no. No because it illustrates that (many) humans can discern differences up to around that speed and higher. Take for example an arcade racer - the difference in the 'speed rush' between 30 and 60 is perhaps the best example - at 30, racing games (with close to the floor camera angles especially) seem really sluggish and boring - at 60 and above, you start getting the 'oh my god, this speed feels real' factor and you get a nice rush of adrenaline. 30 just isn't very close to reality, and without motion blur just doesn't convery high speeds very well. > Although 60Hz in a game does indeed feel somehow "nicer", it is not (to me) > obviously _prettier_ than 30Hz. I take your point, and it all depends on what you're shooting for. However, motion is the key - if you want a close-to-life sensation of real speed or smooth/realistic movement, high framerates rule. I think there's a good reason why FPS gamers are more highly tuned to it than others - FPS' are essentially a simple form of VR. People experience the world as they do normally (to some extent), and therefore strive for ever greater realism, inluding real-life smoothness. Anything less can cause motion sickness on the extreme end of the scale, or simply irritation (and everything inbetween). > Incidentally, 24fps panning at the cinema does EVIL things to my eyes - can > no-one else see it? It's really really awful and stuttery and blurry and yuk > - ruins a good movie. Roll on digital projection.... Oh yeah. It's a mess. Best when your sitting really close to the screen - enough to make you puke :). -- gl |
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From: jason w. <jas...@po...> - 2000-07-31 23:39:54
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> > Incidentally, 24fps panning at the cinema does EVIL things to my eyes - > can > > no-one else see it? It's really really awful and stuttery and blurry and > yuk > > - ruins a good movie. Roll on digital projection.... > > Oh yeah. It's a mess. Best when your sitting really close to the screen - > enough to make you puke :). Yeah.. usually what's happening there is that they're shooting with way to fast a film.. so they shorted the exposure window to a small portion of the 24sec period, or they drop frames if the camera was rollign at a higher framerate. Some movies use this as an intentional effect.. I think the first (biggest) was saving private ryan.. it has a nice effect of eliminating all motion blur. in many ways, this is the same perceptual problem current games have.. lack of motion blur ruins the sensation of continous motion.. I _do_ think that rendering at 30fps with *good* motion blur may feel as "nice" or "nicer" than rendering at 60 fps without it.. but motion blur is such a fill burn we'll have to wait a cycle or 2 before truely exploiting it (sorry... the 4 way sampling 3dfx is pushing doesn't cut it, at least for me, but it is a step in the right way). I've been thinking about splat based rendering a lot lately.. one of the advantages is you could hack in motion blur like this fairly easily, and the fill rate overhead is proportional to the amount of moving splats and the severity of their movement, not constant accross the entire frame. ohh.. btw, most cinema projectors actually flash each frame twice before advancing to the next. they only started doing this as theaters started getting larger and larger screens.. as the screen starts to dominate more and more of the viewers fov, the viewer becomes more and more sensitive to flashing, aliasing and so on. good to keep in mind when the norm right now is a gamer sitting 2" away from a 19" monitor :) |
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