SteamVR Resolution not native anymore

[DannyDan]

I just recognized, that the resolution which is shown in steamvr is set to 3804x3160. I havent changed anything in the Pitool. Field of View is set to normal, render quality is 1.0. Parallel Projection, smart smoothing, hidden area are all off.
Resolution is at 100% in steamvr but why 3804x3160 and not the native resolution 3840x2160?

Super strange as this was correct before.

[dstar]

The resolution at 100% has always been higher than native because the correction profiles are taken into account. Native would have to be somewhere around 70%. (I only use Pitool 1.25 myself, there it’s natively around 35-40% Steam SS.

[DannyDan]

I dont know, I am pretty sure that the resolution was always native when I had the same settings in Pitool. With FOV set to normal and render quality at 1.0 I always had the native resolution set in steamvr.
I am 100% sure, because I used fpsVR and optimized the s**t out of ACC to run as nice as possible with my 4090.

I am using Pitool 1.0.1.284v

[dstar]

Nope, native rendering in VR is already downsampling.

[DannyDan]

“Nope, native rendering in VR is already downsampling.”

But fpsVR was showing me 100% and the resolution of 3840x2160.

[dstar]

can not much say about FPS VR. Maybe it shows the HMD panel data. In normal FOV, the value would be completely wrong anyway, since the panel is not used in its full width. (even including the masked area) Geometrically, VR images have nothing in common with flat

It’s hard for me to tell it in English. Google about VR rendering + barrel correction etc. You will surely find pictures where there is a massive bulge. This has to be factored out again so that it looks natural to the eye.

[DannyDan]

“It’s hard for me to tell it in English”

Deutsch wäre kein Problem.

Wenn ich das im Pitool dann mal wie bei dir auf 1.25 setze und in SteamVR auf 70%, dann lande ich bei 3980x3304?!?

Ich bin mir sowas von sicher, dass es bis vor ein paar Tagen noch in SteamVR bei 100% korrekt angezeigt wurde mit 3840x2160.

Wenn ich jetzt z.B. auf Large gehe im Pitool dann habe ich auch nicht mehr 5190x2160 sondern 5084x3160. Auch da sind es nun ganz andere Werte?!?

[dstar]

Die SteamVR Werte schwanken zwar mit jedem Pitool (oder jedem anderen Herstellertreiber) etwas, da die Entzerrprofile immer weiter optimiert werden, aber glaub mir, allein vertikal liegen die Renderdaten bei 100% schon immer, je nach HMD, zwischen 20-40% über der nativen Display Auflösung. Das erfolgt um eine gleichmäßige Größe der Pixel zu erreichen. 100% Steam entsprechen hier dem vom jeweiligen Hersteller empfohlenen Wert, wo der Großteil einem nativen Äquivalent über das dargestellte Bild entspricht, also, jeder Pixel im HMD bekommt ohne Supersampling mindestens auch die Daten eines Pixels im Game, egal wie gestaucht oder gedehnt ist.
Ohne diese Verfahren würde ein einzelner gerenderter Pixel im Zentrum z.b. über 2-3 physikalische gestreckt werden. (grob erklärt)

3xxx vertikal sind für die 8kx auf jeden Fall bei 100% korrekt.

Solltest Du vorher weniger Pixel gelesen haben, hattest Du vermutlich Ingame die Auflösung runtergedreht. ACC hab jetzt nicht, aber in DCS nennt sich das z.B. Pixeldichte.

[DannyDan]

“Solltest Du vorher weniger Pixel gelesen haben, hattest Du vermutlich Ingame die Auflösung runtergedreht. ACC hab jetzt nicht, aber in DCS nennt sich das z.B. Pixeldichte.”

Ne, ich habe die Auflösung ja nicht nur InGame gesehen, sondern auch direkt in den SteamVr Einstellungen bei “Auflösung pro Auge”.

[dstar]

egal wie und was 2160 v sind falsch.

[DJSlanr]

No SteamVR was never 100% 5190x2160.

ASSUMING YOU HAVE an 8KX:

For Parallel Projections on it is 3980 vertical.
For PP off it is 3160 vertical.
Horizontal resolutions are a factor of the FOV

For PP OFF
Small
3158 x 3160
Normal
3834 x 3160
Large
5112 x 3160

FOR PP ON
Small
3264 x 3948
Normal
4456x x 3948
Large
7716 x 3948

Note these provide the same PPD and are determined to be an approximation of the resolution that would produce a native density across the very center of the display based on the distortion profile; thus providing you the best clarity the display can provide natively…

After much digging for an answer to “Where does the 3160 come from exactly”? To my surprise: it should initially come from simply the square root of 2 times the display resolution (2160), which actually comes in at 3055 vertical for the PP off mode. To the contrary of what I first thought, it is not to produce a 1:1 pixel density “in spite of barrel distortion”, but rather to ensure there is 1 pixel per pixel at the most extreme angle (45 degrees) of the display grid vs. rendered grid. That’s where the square root of two comes from. Believe it or not: barrel distortion has no effect at the super-center of your display in non-PP mode. The 1.41 factor also provides a larger area that is at or above the resolution needed for that 1:1 pixel across a larger cone of the display, so it has TWO improvements there.

But of course more people recognize the importance of supersampling which occurs naturally as a result of super-resolution and the eye perceives this as increased clarity.

The reason for the 3948 vertical resolution being used for the PP off version is a little less clear to me but has been reported to be a combination of the result of the shape of the distortion - and also that the center of the sharpest part of the distortion is also offset by canted displays.

I don’t claim to be an optician, technical expert or anything other than a VR fan, but I would reference @risa2000 for more information. This along with some early technical papers I simply googled regarding Oculus’s early attempts at eliminating “Moire” and accounting for barrel/pincushion distortion were very informative. I invite further clarification, insights and references.

[DannyDan]

Yes, I have an 8kx.

So I just set the different settings too and I get the following when looking at the settings in steamvr:

For PP OFF
Small: 3128x3160 → 100%
Normal: 3804x3160 → 100%
Large: 5084x3160 → 100%

FOR PP ON
Small: 3320x3948 → 100%
Normal: 4596x3948 → 100%
Large: 8312x3948 → 100%

So my question is, why dont we get the same values for each setting?

[dstar]

@DannyDan

So my question is, why dont we get the same values for each setting?

Horizontal is IPD dependent

[DannyDan]

THANKS! Now it makes sense.

[risa2000]

@DannyDan @DJSlanr
You might want to have a look at some old posts of mine:

How the render target resolutions and the supersampling factors of Pimax and SteamVR work together

I have already expressed it in many replies, but since there are still new people coming in and being confused I decided to dedicate the thread to this topic. First I need to point out that all numbers I will present later were: recorded at Pimax 5k+ running, PiTool v1.0.1.91 and firmware v181 They should not change between the different versions, because they are basically defined by the optics, which does not change either, but its good to keep it in mind anyway. How OpenVR (SteamVR) works OpenVR subsystem (which is exposed as SteamVR app to the user) uses a headset driver (which is act…

All the parallel FOVs of Pimax 5k+

This post is a follow up to my original post on the subject (All the different FOVs of Pimax 5k+), which should be probably rather renamed to All the native FOVs of Pimax 5k+ as all it addressed were the FOVs, when parallel projection (PP) was turned off, but I leave it as it is. I did not really expect that PP on would change the FOV(s), it would change the actual view geometry, but should not change the overall FOV (both one eye and stereo). However inspired by @VTS post (Parallel projections option renders too big vertical FOV and 25% performance is lost) I decided to redo the analysis wit…

All the different FOVs of Pimax 5k+

Recently I was looking at projection matrices and from where they come and realized that there is actually finally the info available about what the different FOVs offered by Pimax mean. Just for the record I should state that I run the tests on: Pimax 5k+ PiTool v1.0.1.91 (HMD Firmware v181) Parallel projection OFF If for some reason Pimax decide to change the headset characteristics, these results become obsolete. They also may differ for Pimax 8k. EDIT 15.4.2019: I have added another post to address the configuration with the parallel projection turned on (All the parallel FOVs of Pima…

The first one in particular explains (or at least tries ) why there is no direct relation between the display resolution and the rendering resolution.

Unfortunately, the links in posts do not work anymore as Pimax changed the forum domain and did not change the links. So I am listing them here explicitly. If you find other links which do not work, try changing .ai top level domain in the URL to .com.

EDIT: Seems to be fixed now, thanks to @Heliosurge

[Heliosurge]

@risa2000

Unfortunately, the links in posts do not work anymore as Pimax changed the forum domain and did not change the links. So I am listing them here explicitly. If you find other links which do not work, try changing .ai top level domain in the URL to .com.

As per your DM to me these particular posts are fixed up now. Thank you for reaching out!

Anyone finding old posts they need image display and/or links fixed please dm me the links to the affected posts.

[DJSlanr]

Oh these losts are golden!