Improved VR performance by cropping.

[Flighter]

Hi all !

 

I though I'd share this as it makes a real improvement in FPS. Of course nothing is really free in life, and for this one you pay with smaller image size.

Some may find it appalling some may tolerate it.

It's still an option and for some systems missing just a couple of frames per second to lock to 45, 90 or whatever your target is, it may be valuable.

I also attach a spreadsheet that I used to get an understanding of the impact of Pixel density and image size (as in rendered pixels) on the system.

Just remember that shaving off from the edges even a little may make a substantial difference because we are talking "area" so numbers are multiplied...

 

I do not know if other HMDs than the Oculus's have this setting...

In Oculus debug tool use the "FOV-Tangent Multiplier" section. In there the two numbers crop the rendered frames by the multiplier specified. (1 means no cropping).

 

Use the attached openoffice calc sheet to see the effects on pixels required by the system for various VR headsets.

The blue cells are drop-down lists.

Select your device, PD and cropping factor and see the results.

The green cells show the percentage of more (or less) work the system has do.

The big table makes easier to understand the equivalent settings taking in consideration the characteristics of each device.

For example: A PD of 1.5 for the rift makes the system render 5.6 MPixels

Same PD on the rift S will require 7.9 MPixels.

From the table it is apparent that a PD of 1.2 or 1.3 for the rift S would have (more or less) the same effect (at least on system performance as image quality is also affected by the down-sampling ratio, blur radius used etc etc).

 

Merry Christmas all !

 

 

Oculus debug tool :

 

Pixel Density Calculator :

 

PixelDensityCalculator.zip

Edited December 24, 2019 by Flighter

[fitness88]

All the Oculus tools except the Oculus Tray Tool can be found in:

C:\Program Files\Oculus\Support\oculus-diagnostics

 

Has anyone tried using all these to see what they do?

 

https://forums.eagle.ru/attachment.php?attachmentid=223752&stc=1&d=1577317980

[sirrah]

Hey Flighter, thank you for sharing! :thumbup:

 

Could you explain to me what you mean by "a smaller image size"?

 

Do you mean it effects fov?

[jozeff]

Mmmm, very interesting

Thank you.

 

 

Do you mean that your fov will be smaller so that you get black bars on the sides?

 

 

Or will the resolution on the edges be smaller?

 

 

Jozeff

[toutenglisse]

Yes it cuts black bars left/right - up/down. Even with 0.9 by 0.9, when looking strait forward I can now see a box. Bad. (looking at borders of lenses I don't see it but forward it's obvious)

 

In this kind of tweak, what Kegetys did was much smarter than what Debug Tool does : round rendering zones instead of rectangular ones, so only invisible corners were cut off while sides (up/down - left/right) were rendered fully.

But the rendering zone tweak by Kegetys is sadly not available alone, but also with shaders mod that gives perf but takes good DCS visuals at the end...

[sirrah]

Aww, that's too bad then, sure I want better performance, but not at the cost of fov

 

Still, nice of you to share Flighter

[fitness88]

I tried it, didn't see much help in frame rate...even increased the percentage of blocked view.

Tried the other options, nothing much changed.

[GunSlingerAUS]

Alas, dcs in VR has major issues, including bad and unstable performance.

[imacken]

Alas, dcs in VR has major issues, including bad and unstable performance.

 

Not for everyone, it hasn’t!