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jestersdance
11-25-2013, 04:05 AM
Back in the days of Quake 3, you had to squeeze every bit of your hardware to get 125 FPS.

Your eyes wouldn't notice the difference between 50 or 125, but strafejumping was pretty hard below 125. Fair enough, I couldn't do even basic jumps (like the famous rail-to-bridge) if my FPS was lower than 125, but it all worked perfectly when your PC was powerful enough to keep it steady at that number.

It also becomes prominent in racing games, in which it'll become very difficult to control your vehicle when you're in an area that makes your rig sweat. Also there are tons of old games which developed physics bugs on new computers simply because the FPS is way too high than originally intended. Grim Fandango's forklift scene is one example I recall.

So, how does framerate correlate with physics? I'll give 1000 imaginary dollars to the person who explains it to me :D

trojanrabbit.gg
11-25-2013, 04:13 AM
A quick web search gave me this info...

http://www.bulletphysics.org/mediawiki-1.5.8/index.php/Framerate_Independence

Ishan451
11-25-2013, 05:34 AM
Back in the days of Quake 3, you had to squeeze every bit of your hardware to get 125 FPS.

Your eyes wouldn't notice the difference between 50 or 125, but strafejumping was pretty hard below 125. Fair enough, I couldn't do even basic jumps (like the famous rail-to-bridge) if my FPS was lower than 125, but it all worked perfectly when your PC was powerful enough to keep it steady at that number.

You don't see a differance, but the number of frames dictate when input can occur. (I actually doubt anyone can see a differance between 40 and 60fps... i even believe the majority of humans don't see one beyond 30)

A game can only receive a new command with a new frame. Which means if you have 120 Frames per second, you can have 120 inputs, as opposed to having only 30 Frames per second where you can only have 1/4 of that.

So naturally if you have a very short margin of time in which you can pull off a certain move (strafejump), you want to have more frames in order to successfully pull it off. In theory, if you had a macro that would ensure the move is carried out regardless of your frame rate, you wouldn't need high FPS for Quake 3 either.

Having higher FPS makes a game more responsive to your input.

So, how does framerate correlate with physics? I'll give 1000 imaginary dollars to the person who explains it to me :D

These days Games are processed (and developed) by the frame. Stuff happens frame by frame in the game, just like a movie. It used to be tied to CPU ticks before the 90ties, now its frames.

Like when you see a character swing a sword. These days games will use physics to caliclate where the sword should be, and if it hits something in between, frame by frame until it reaches its end point. Which makes for a much more 'fluid' swing animation. Really good games, then will give a weight property to objects, to let the swing being caluclated (you usually see that in games where the momentum and weight of an object decides how much impact it will have)

Your computer doesn't calculate that stuff independently, but does so by the frame. Its why Physix Cards are usually combined with your graphic card.

On each new picture (frame), your computer decides where stuff has to be in order to be displayed. And while most stuff has a limitation coded in, to prevent the situation we have in.. lets say the Battletech RPG Crescent Hawk, where the fight would be over in less than a second due to it being tied to CPU ticks... some of the physics stuff just isn't limited, because its considered unimportant, or because there is a general limitation in place.

Like say the new Need for Speed, where Total Biscuit had to come up with some rant because he removed the Framelock of the game and then complained that the game wasn't optimized (physics and carspeeds) not being limited in another way, but rather tied to frames. Which made his car 2-3 times faster than the rest of the game, and other physics being totally shot.

The Devs simply didn't bother to add more limitations into the game, once they decided to lock the game to 30fps anyway.

jestersdance
11-25-2013, 06:11 AM
Thanks, very informative. +repped :)

trojanrabbit.gg
11-25-2013, 06:30 AM
You don't see a differance, but the number of frames dictate when input can occur. (I actually doubt anyone can see a differance between 40 and 60fps... i even believe the majority of humans don't see one beyond 30)


I beg to differ. I can see the difference between 30, 40, 60, and 120 easily.

Porcupeth
11-25-2013, 07:28 AM
(I actually doubt anyone can see a differance between 40 and 60fps...

Oh i can see it. I wish i didn't, but it pratically screams at me "i'm slowing dooooooowwn"

Lethal_Sting
11-25-2013, 07:39 AM
Here's the info (http://www.funender.com/quake/articles/fps.html) for Quake 3 Engine and how fps altered your jump distance.

Basically, your position is calculated every time a frame is rendered by Quake. So if you are using a higher framerate, your position will be calcualted more times per second.

But the biggest effect is due to the velocity also being rounded to an integer, in order to save bandwidth, which gives large framerate-dependent rounding errors.

This means there is a rounding error in the results of Quake's calculations and it is these rounding errors which causes the differences in movement - most noticeably when jumping.

Indeed, many players say they feel like they are 'floating' when they first try one of the magic framerates that has a large effect, such as 125fps.


Being that CoD was also based on the Quake Engine, framerate also applied to that game.

And let's not get into the whole "humans can't see over 30fps anyway" spiel.

marie pavie
11-25-2013, 09:57 AM
So, how does framerate correlate with physics? I'll give 1000 imaginary dollars to the person who explains it to me :D
I'll bet that all the frameworks explained about this are conceptually wrong anyway. If you make any assumptions at all about what specifically a computer is doing you're off into la la land as far as theories go.

Ishan451
11-25-2013, 10:05 AM
Hey, Lala Land is a magical place... don't knock it.

And let's not get into the whole "humans can't see over 30fps anyway" spiel.

Not planing to :) Been there and done that way to often. Neither side can prove what they perceive or not, because it doesn't get more subjective than perception.

bluz74
11-25-2013, 10:08 AM
it doesn't get more subjective than perception.


That fact depends on your point of view.

Levi
11-25-2013, 10:10 AM
I'll get into it. :)

http://boallen.com/fps-compare.html

Its not hard to see the difference between 30 and 60 FPS at least.

Ishan451
11-25-2013, 10:17 AM
I'll get into it. :)

http://boallen.com/fps-compare.html

Its not hard to see the difference between 30 and 60 FPS at least.

Nice example for how animation speeds are tied to framerate. Still don't see a differance *shrugs* between 30 and 60.

Benji90
11-25-2013, 10:23 AM
Having the framerate affect physics is a major problem for me in UDK. With the iOS game I am developing at the moment, the physics has to be constant every playthrough so I have to lock the FPS to 40 which is the lowest it will go on iOS devices. I wish they coded the engine in a different way so this wouldn't be an issue, apart from that UDK is great.

GirlPower23
11-25-2013, 10:31 AM
Your eyes wouldn't notice the difference between 50 or 125

That's completely false.

JustAnotherFan
11-25-2013, 11:27 AM
I beg to differ. I can see the difference between 30, 40, 60, and 120 easily.

It's going to turn into one of those threads.

jestersdance
11-25-2013, 01:37 PM
That's completely false.

That was the entire point of my thread, thank you for correcting ._.

Here's the info (http://www.funender.com/quake/articles/fps.html) for Quake 3 Engine and how fps altered your jump distance


Very interesting, never knew that :) Thanks!

mlcarter815
11-25-2013, 01:49 PM
Nice example for how animation speeds are tied to framerate. Still don't see a differance *shrugs* between 30 and 60.

You seriously can't see the difference? I wish I could say the same.

Ishan451
11-25-2013, 02:05 PM
You seriously can't see the difference?

Not really, no. At first i thought i could, since the 60 frames one seemed to be faster, but after i watched it for a moment, i had to concede that they look about the same to me, when i do a side by side comparison.

mlcarter815
11-25-2013, 02:19 PM
Here is another demo.

http://frames-per-second.appspot.com/

Ishan451
11-25-2013, 02:28 PM
Here is another demo.

http://frames-per-second.appspot.com/

That one doesn't work properly for me. When i look at the top right, at the small dot, and the information about the Animation speed and the like, it shows the animation to stutter on my end. No idea why, tho.

Levi
11-25-2013, 02:34 PM
Not really, no. At first i thought i could, since the 60 frames one seemed to be faster, but after i watched it for a moment, i had to concede that they look about the same to me, when i do a side by side comparison.

Well, I meant it to prove the opposite, but honestly its probably a good thing for you if you can't tell the difference. :) I wish I couldn't tell the difference.

Ishan451
11-25-2013, 02:37 PM
Well, I meant it to prove the opposite, but honestly its probably a good thing for you if you can't tell the difference.

It is. I am never bothered by a game being a 'terrible' console port, because its locked to 30fps :)

rotNdude
11-25-2013, 02:53 PM
I always thought physics affected frame rate. If the physics consumed too many computer resources, then the frame rate would drop to abysmal levels and the game wasn't enjoyable.

mlcarter815
11-25-2013, 03:18 PM
It is. I am never bothered by a game being a 'terrible' console port, because its locked to 30fps :)

You're lucky. Those console ports locked at 30fps give me motion sickness due to the choppy animation.

MrChris
11-25-2013, 03:24 PM
120hz monitor, gotta love em

closest I've come to the glory days of those silky smooth CRTs

hell yes I can tell the difference between 30fps and upward, fps drops are noticeable even if they remain well into the playable range