Jump to content


* * * * * 1 votes

Success! I Finally Got Gpl To Work On My Triple Screens!


  • Please log in to reply
42 replies to this topic

#1 n1ascar

n1ascar

    John Surtees

  • Members
  • PipPipPipPipPipPipPip
  • 39 posts

Posted Mar 14 2013 - 06:51 AM

Hi all,
Last night was great. I finally after MANY attempts got GPL to work on my triple screen setup.
It really was a site to see. At first FOV and steering were off but with minimal tweaks i worked past those problems.
I will try to post some pictures tonite and some more info if anyone is interested.
Thanks to the communitte for all the post ii have read that helped!
Kris Craig

#2 Pedro

Pedro

    Pedro

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 1,355 posts
  • Gender:Male
  • Location:Hillegom - The Netherlands
  • Interests:Grand Prix Legends
    Scuba-diving
    Airplanes
    Money :-)
  • Sim interest:GPL

Posted Mar 14 2013 - 01:18 PM

View Postn1ascar, on Mar 14 2013 - 06:51 AM, said:


I will try to post some pictures tonite and some more info if anyone is interested.

What do you think Kris   :up: :GotPics: :camera: :this_thread_is_useless_without_

#3 n1ascar

n1ascar

    John Surtees

  • Members
  • PipPipPipPipPipPipPip
  • 39 posts

Posted Mar 14 2013 - 04:51 PM

Working on photos and video now. Hope to have up later tonight!
Kris

#4 n1ascar

n1ascar

    John Surtees

  • Members
  • PipPipPipPipPipPipPip
  • 39 posts

Posted Mar 14 2013 - 05:20 PM

here are a few pictures. Video is uploading now

Attached File  IMG_0253.JPG   60.64K   181 downloads


Attached File  IMG_0254.JPG   68.74K   194 downloads

Attached File  IMG_0255.JPG   56.32K   160 downloads

Attached File  IMG_0256.JPG   65.22K   136 downloads

Kris

#5 n1ascar

n1ascar

    John Surtees

  • Members
  • PipPipPipPipPipPipPip
  • 39 posts

Posted Mar 14 2013 - 07:12 PM

Here is a short video.



Hope you enjoy it!

Kris

#6 Bob Simpson

Bob Simpson

    The answer man

  • Moderator
  • 2,303 posts
  • Gender:Male
  • Location:Ottawa
  • Sim interest:GPL

Posted Mar 14 2013 - 08:28 PM

That's great Kris.  What FOV are you using?  Why do the cars look elongated in the side screens?

#7 n1ascar

n1ascar

    John Surtees

  • Members
  • PipPipPipPipPipPipPip
  • 39 posts

Posted Mar 15 2013 - 09:57 AM

Bob
Will check FOV when i get home tonite.
The elongated cars are greatly exaggerated in the video. If you notice  as i pan to the side. The monitor's look way longer that the center montior. When actually they are all the same size..  (22" Acer's)
So i guess it a optical illusion caused by the camer i used.
Kris

Edited by n1ascar, Mar 15 2013 - 09:59 AM.


#8 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 312 posts
  • Sim interest:GPL and P&G

Posted Mar 15 2013 - 03:29 PM

The reason things look elongated in the further you get from the centre is due to rectilinear distortion. There is no way around this unless the game is coded to support 3 separate viewports (like iracing, rfactor2 (multi-view) and assetto corsa). With 3 separate viewports, you can sort of half-emulate a cillindrical FOV, which is a lot more natural.
Viewing stuff on a flat surface is not natural - it's not how your eyes see - or in fact cameras. If you have a really high FOV then as you get further and further to the edge, things get more and more stretched.
It's sad because no non-racing games support 3 screens properly that i am aware of. Maybe some flight simulators, but i wouldn't know. Certainly nothing mainstream.

Strictly speaking, if multi-view is not supported, then the 3 screens should be laid out horizontally, with no angle, as the image being displayed is meant to be one large flat image. You are supposed to be viewing the direct centre of that image, and therefore due to how your eyes see, any distortion towards the edge is not picked up by your eyes and is "corrected", due to the angles involved.

This won't work for you though, as you are using a very incorrect FOV.
For 3 screens, gpl appears to use a horizontal FOV (for one screen probably too, though when i tried it here at home, the 1 screen fov seemed too wide if i did it horizontally :|).
A lot of old games use a horizontal FOV value and then calculate (base) the vertical one on that, according to your aspect ratio. This isn't ideal, as it means if you get a wider monitor / 3 screens then you have to calculate the fov again, as you have changed your horizontal viewing area.

With more modern applications, you would hope they would use a vertical fov in order to calculate the horizontal, based on your aspect ratio. This doesn't always seem to be the case.





Anyway, if you got bored of the rest of my ramble, read and try at least this part:

First we will calculate your vertical field of view.
You will need to measure:
  • The height of your screen
  • The distance from your eyes to the screen.

Then you can use this formula:

2 * arctan(screen height / (2 * distance from screen) ) = Total vertical FOV

(arctan is the tan-1 thing, the inverse tangent)

You can then use this for all games that use a vertical FOV value.
Thankfully, it is very easy to calculate a horizontal FOV from this - even with bezel compensation if you use the bezel compensated res width in your calculation.
Simply:

Vertical Fov * horizontal resolution / vertical resolution = Horizontal FOV
(this assumes your pixels are square - if not, then use aspect ratio instead - though if using 3 screens you will need to measure the width so that bezels are taking into account).


My silly assumption that you could simply ratio the FOV via aspect ratios was partially incorrect - you can but not from the FOV - only from the screen height value, redoing the calculation. It is still useful to use the vertical height though, as this is easier to measure accurately rather than worrying about bezels etc.

So, to get the horizontal field of view, you need to do the aspect ratio conversion inside the FOV calculation formula.
Therefore:
2 * arctan( (screen height * horizontal resolution / vertical resolution ) / (2 * distance from screen) ) = Total horizontal FOV



You need to set this calculated FOV in GEM and then switch car in switch back in order for it to activate (you dont need to launch, just choose a different one from the dropdown box and then change back).

You will find that doing this will greatly improve your driving experience and really help you to appreciate the reality of distance, especially for things like braking areas. No longer is distance horribly distorted as it was using an incorrect FOV (effectively like watching the game through a camera, rather than "being there").

A downside is that pitboards aren't really very viewable at very low FOVS.

Gplshift seems to be able to move the pitboards to make them still visible. The sad part is it locks the minimum fov to 45 for some stupid reason, so is not a viable option unless you have a huge screen and put it really close. For that reason, i would recommend using GEM instead.

I really wish GEM would move the pitboards into your FOV or that gplshift would remove it's arbitrary FOV limit.

Anyway i hope this helps - you can do the same thing in every game you play, providing it has the ability to set FOV somewhere. It really makes a huge difference.


I tried it in nr2003 but for some reason the only FOV hack i could find actually broke the rendering of the game so if anyone knows how to do it in nr2003 properly then please let me know!!

Edited by one2fwee, Apr 10 2013 - 06:27 PM.


#9 M Needforspeed

M Needforspeed

    Denny Hulme

  • GPLLinks Team
  • PipPipPipPipPipPipPipPipPipPip
  • 2,469 posts
  • Gender:Male
  • Interests:GPL - start a collection of GPL era die cast racing cars -Skiing
  • Sim interest:GPL

Posted Mar 16 2013 - 06:12 AM

very very interesting post one2fwee ! :up:   Haven 't a triple screen, but first thing I will do is apply carefully your tuto if one day I get one

Edited by M Needforspeed, Mar 16 2013 - 06:15 AM.


#10 Pedro

Pedro

    Pedro

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 1,355 posts
  • Gender:Male
  • Location:Hillegom - The Netherlands
  • Interests:Grand Prix Legends
    Scuba-diving
    Airplanes
    Money :-)
  • Sim interest:GPL

Posted Mar 16 2013 - 08:57 AM

View Postone2fwee, on Mar 15 2013 - 03:29 PM, said:

Anyway, if you got bored of the rest of my ramble, read and try at least this part:

First we will calculate your vertical field of view.
You will need to measure:

o- The height of your screen
o- The distance from your eyes to the screen.

Then you can use this formula:

2 * arctan(screen height / (2 * distance from screen) ) = Total vertical FOV

(arctan is the tan-1 thing, the inverse tangent)

You can then use this for all games that use a vertical FOV value.
Thankfully, it is very easy to calculate a horizontal FOV from this - even with bezel compensation if you use the bezel compensated res width in your calculation.
Simply:

Vertical Fov * horizontal resolution / vertical resolution = Horizontal FOV
(this assumes your pixels are square - if not, then use aspect ratio instead - though if using 3 screens you will need to measure the width so that bezels are taking into account).


You need to set this calculated FOV in GEM and then switch car in switch back in order for it to activate (you dont need to launch, just choose a different one from the dropdown box and then change back).


I don't get it
My screen height is 30cm (wide=116cm) and my distance to the screen is 70 cm .............. what is my FOV?
And do I only have to set this in GEM+?

Thanks

#11 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 312 posts
  • Sim interest:GPL and P&G

Posted Mar 16 2013 - 10:09 AM

View PostM Needforspeed, on Mar 16 2013 - 06:12 AM, said:

very very interesting post one2fwee ! :up:   Haven 't a triple screen, but first thing I will do is apply carefully your tuto if one day I get one

You can do this on a single screen just fine - in fact that's what i use it for (i don't have 3 screens at home).
You probably won't be able to see your mirrors unless you use the look left / right buttons.

To be able to increase your FOV and still have it realistic, you need to increase your screen size or move the screen closer to your eyes.


View PostPedro, on Mar 16 2013 - 08:57 AM, said:

I don't get it
My screen height is 30cm (wide=116cm) and my distance to the screen is 70 cm .............. what is my FOV?
And do I only have to set this in GEM+?

Thanks
Okay, that aspect ratio seems a bit strange so i just want to be sure i understand correctly before calculating it for you.

How many screens are you using?
What resolution will you be using?

I might need to explain about bezel compensation if you are using 3 screens - unless you understand that already.

#12 Andreh

Andreh

    Denny Hulme

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 192 posts
  • Gender:Male
  • Location:Rio de Janeiro, Brazil
  • Interests:Pre-80's racing
  • Sim interest:GPL

Posted Mar 16 2013 - 01:16 PM

the problem with realistic FOV is that in simracing we already have so fewer info on whats going on with the car and around , that if we do it realistically we will have even less info.
I use the max fov GEM allows, 120 afair, with little tweak in seat position

#13 Pedro

Pedro

    Pedro

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 1,355 posts
  • Gender:Male
  • Location:Hillegom - The Netherlands
  • Interests:Grand Prix Legends
    Scuba-diving
    Airplanes
    Money :-)
  • Sim interest:GPL

Posted Mar 16 2013 - 02:23 PM

View Postone2fwee, on Mar 16 2013 - 10:09 AM, said:


How many screens are you using?
What resolution will you be using?

I might need to explain about bezel compensation if you are using 3 screens - unless you understand that already.

I use 3 screens with triplehead2go
The resolution = 3072 x 768
And I do not understand what "Bezel" means (sorry)

Thanks in advance :)

#14 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 312 posts
  • Sim interest:GPL and P&G

Posted Mar 16 2013 - 02:25 PM

Yes, you will have less view of your surroundings, but the most important view is directly in front of you.
If you have side screens, or even a wide screen monitor, i would definitely suggest a realistic FOV. You don't have to go that low, as long as you put the screen as close as possible.

You can still have an understand of where other cars around you are. Use sound - you can hear them!
Headphones are a great help in this, particularly if you have a soundcard that can support a form of hrtf such as an asus card, or a creative card (it's called cmss in that case) or a3d or something.
Even without that, headphones help a lot.
To complement that, you have the look left and right buttons on your wheel.


If you use a too high FOV then everything becomes horribly distorted so that you cannot judge the distance properly at all.
Ever wondered why a lot of people crash into the car in front online? A lot of this is down to incorrect FOV making it seem like the car ahead is a lot further away than they actually are. This is all down to FOV.

A correct FOV is not only a much more natural and nicer experience, it will also make you faster and much more consistent. The only problem might come from turning into hairpins, if your monitor(s) is too small / far away so that you cannot see what you are turning into properly.

#15 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 312 posts
  • Sim interest:GPL and P&G

Posted Mar 16 2013 - 02:48 PM

Okay Pedro, I am not quite sure how triplehead2go works.

From what i can tell, you have 3 monitors of 4:3 aspect ratio (1024 * 768).
What bezel compensation is, is basically accounting for the width of the bezel / frame of the monitor.

For example, your normal resolution for 3 screens might be 3072 * 768 but that is not compensating for the bezel.
In order to take account of the bezels, you must set up something with your triplehead2go. I don't know how this works as i don't have it but this video says that you need to do something called "bezel management", so look for that.

If it works like eyefinity (which i assume it does), then it should give you a "bezel compensated" resolution after doing the bezel management. It is this that i need in order to help you calculate it properly. It is also this resolution that you should set gpl to use (rather than 3072 * 768).
For example, the bezel management could suggest a resolution of 3520 * 768.



Anyway, i will do it for your current resolution. Please be aware that this will not look correct yet as it doesn't take the bezels into account but i cannot help with that until you have set up your bezel compensation.

So:

2 * arctan(30 / (2 * 70) ) = 24.1895......
So your vertical FOV is about 24.2 degrees.

Now, gpl appears to use a horizontal FOV so we need to convert that. (This is the part that will change based on bezel compensation).


24.1895... * 3072 / 768 = 96.758....
So your horizontal fov is approximately 97 degrees.

Therefore, you need to set the FOV in GEM to 97 (and change car and change back, to make sure GEM applies the changes).


2 * arctan((30 * 3072 / 768) / (2 * 70) ) = 81.2025......
So your horizontal FOV is about 81 degrees.


This will be different once you have calculated your bezel compensation, so feel free to tell me and i can help you again once that is done.
This really isn't super difficult once you get the hang of it though and it would be cool for more people to understand this as it makes a big difference!

Edited by one2fwee, Apr 13 2013 - 09:24 AM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

Sim Racing Links