Debunking DPI Continued

by im a tree • 15 Dec 2008, 20:31 • Journals
Just read this on ESR.

warning: Most of you won't give a shit. Don't waste your time.



Quotethe mouse resolution determines the smallest angle you can rotate your view by in game, for a given sensitivity.

if you want this smallest angle to be small enough so that you can turn your view by 1 pixel (to the pixel next to where your crosshair is), you need to know what angle that distance of 1 pixel represents on your screen.

the current method that everyone seems to use calculates the average number of degrees per pixel over the whole screen. this is wrong, however it is the simplest mathematically.

the projection of the 3D world onto the 2D plane of your screen (read: fishbowl effect), means the pixels located near the crosshair represent much larger angles than those pixels located at the edges of your screen.

so to do the calculation properly, you have to calculate how many degrees a single pixel represents at the centre of the screen.

if you do it properly, you get:

R = ( pi * W ) / ( I * tan[ F / 2 ] )

where
W = screen resolution width
I = real sensitivity (distance per 360 turn)
F = horizontal fov

R = mouse resolution required


convert your sens to inches if you want R in units of dpi.


I worked out I only needed around 60DPI from a mouse at my current settings

but, I wondered if I really did need to raise my DPI when playing under native LCD res or if it was just placebo.

Using this formula, I take

W = 1680
I = ~30 inches (75cm/360)
F = 110

sub it all in

(3.141592654*1680)/(30*Tan(110/2))
and I get 123.186944066 DPI required.

Which means I can continue using 400DPI pretty much "4 lyf"


tldr - unless you are a high senser playing at LCD native resolutions, take an IME3.0 or WMO1.1 instead of overspending on a DA/MX518 (coming from someone who did overspend on a DA ;_;) Disclaimer: unless you actually prefer the feel of those mice, because with a mouse feeling is by far the most important factor, but I don't think I've met anyone who doesn't like the feel of the MS mice)

edit



QuoteI don't recommend it to ET players, not because of it only having 400dpi but because of low data path bandwith (8-bit if I recall). What that means is that you will have negative accel if you move your mouse fast. If you use 40cm/360 or more it's really a problem to do a fast 180 turn. Deathadder and mx518 don't have this problem (no-one would be capable to move the mouse so fast to make it skip).


I haven't been able to confirm this but it's worth testing.
Comments
36
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perforator 15 Dec 2008, 20:33
e: 261 dpi here.
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CrimZon 15 Dec 2008, 20:40
perfo failed at math? :o
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perforator 15 Dec 2008, 20:42
didn't convert to inches at first :D
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CrimZon 15 Dec 2008, 20:44
ill forgive u...this time.
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Skydeh 15 Dec 2008, 20:33
NO ONE GIVES A FUCK YOU DWEEB
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tactics 15 Dec 2008, 20:34
What is 10 cm for 180 degrees considered in terms of low/medium/high sens?
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im a tree 15 Dec 2008, 20:38
dunno, mid-high?
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perforator 15 Dec 2008, 20:41
mid-high i guess. real high starts at around 4 cm for 180 i'd say :D

I use 8/180.
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tactics 15 Dec 2008, 23:16
Damn all these low-sensers, only high sensitivity aiming requires skill! ;D Can't imagine playing any lower than 20cm/180, even that feels extremely low.

For sniper I use 2cm/180.
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urtier 15 Dec 2008, 20:40
428,5259 DPI needed. :-d
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crumbs 15 Dec 2008, 20:45
187.71

W = 1024
I = ~12
F = 110
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gottie 15 Dec 2008, 20:49
You try to sound smart but in fact you don't have a clue what you are talking about when you recommend those MS mice. Even though I use WMO (and also used ime 3.0 before) for along time, I don't recommend it to ET players, not because of it only having 400dpi but because of low data path bandwith (8-bit if I recall). What that means is that you will have negative accel if you move your mouse fast. If you use 40cm/360 or more it's really a problem to do a fast 180 turn. Deathadder and mx518 don't have this problem (no-one would be capable to move the mouse so fast to make it skip).

I agree with DPI part though. Marketing makes wonders.
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im a tree 15 Dec 2008, 20:56
Never heard of such a problem, I'll have to test it out with my own hardware. Personally prefer the feel of the prediction-less sensor but if what you say is true then I'll need to rethink this

image: predictionfn3
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Deactivated6097 15 Dec 2008, 20:49
228.9351095 am i cool with 400 dpi?
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Budha 15 Dec 2008, 20:49
I doubt any gamer would take anything like this into account before purchasing a mouse
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ETNiES 15 Dec 2008, 20:51
or a bot?
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Budha 15 Dec 2008, 20:52
The things that would be needed to be taken into account would be completely different if purchasing a bot
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ETNiES 15 Dec 2008, 20:53
you wouldnt have to take anything into account as it does it for u.
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ETNiES 15 Dec 2008, 20:50
oh fo u idiot
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overdrive 15 Dec 2008, 20:58
even i couldnt be arsed to read this shit!
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Shuki 15 Dec 2008, 21:13
188.522

I think most people knew that dpi was a gimmick anyway.
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nicon 15 Dec 2008, 21:32
even i couldnt be arsed to read this shit!
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plekter 15 Dec 2008, 21:40
In practice you also need virtually no friction and a very low sensitivity to move your crosshair just one pixel on purpose.
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crook 15 Dec 2008, 21:42
isnt this pretty old? But ye, i used it aswell to determine my dpi
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triflip 15 Dec 2008, 21:47
who the fuck cares? u wont notice it unless ur god.

And try to move ur mouse one pixel, even when you just touch ur mouse ur failing already.
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im a tree 15 Dec 2008, 21:52
bullshit

have you never used any image editing software? it's more than possible to move your mouse exactly one pixel
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Deactivated6096 15 Dec 2008, 21:56
wtf? moving a mouse for one pixel is the easiest thing ever?
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S3ti 15 Dec 2008, 22:06
this is new










not
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quebratolas 15 Dec 2008, 22:29
( pi * 1024 ) / ( 18 * tan[ 105 / 2 ] ) = 137.137
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GoodGuyGary 15 Dec 2008, 22:41
(3.142 * 1024 ) / (6*tan(105 / 2)) = 419.381014
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Reni 15 Dec 2008, 23:43
1028.26

W=1680
I=7~
F=110
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