OpenComposite - Play SteamVR games without SteamVR

"OpenComposite (previously known as OpenOVR - OpenVR for OculusVR - but renamed due to confusion with OpenVR) is an implementation of SteamVR’s API - OpenVR, forwarding calls directly to the Oculus runtime.

Think of it as a backwards version of ReVive, for the Rift. This allows you to play SteamVR-based games on an Oculus Rift as though they were native titles, without the use of SteamVR."

https://gitlab.com/znixian/OpenOVR/blob/master/README.md

As pitool can play oculus games “natively” I wonder if this OpenComposite would work too with the pimax, removing the need for steamVR for steamVR games.

And if it works it may be worth checking if there is any performance gain !

@SweViver @VoodooDE @yanfeng @mixedrealityTV

11 Likes

Hmm VERY interesting, let me have a look into this tomorrow! :slight_smile: Thanks!

10 Likes

This would be huge. I don’t even care if it’s oculus we need the performance and I think steamvr takes a different approach.

3 Likes

I have just tried OpenComposite with assetto corsa competizione on my rift.

I have had to use the 32bits version of openvr_api.dll, I tried the 64bit first and it crashed.
Also you need to create a shortcut of acc.exe and add -vr at the end of the shotcut target.

On my rift performance was the same, although when I swtiched back to the original openvr_api.dll to compare performances I noticed steamVR did not launch, which means ACC has a native oculus support (that was the case for AC already).

That reminded me there is also another way to force VR games having native oculus support to use that instead of going through steamVR.

I discovered that when I was testing pcars2. You have to go to C:\Program Files (x86)\Steam\SteamApps\common\SteamVR\bin\win64 and rename those .exe (to .exe.bak for example):

vrcompositor.exe
vrserver.exe
vrstartup.exe

For pcars2 the result was a significant performance boost (at least at the time of the game release).

2 Likes

What we want is a hack to use oculus asw basically with steamvr devices.

1 Like

Yes of course that would be a dream :slight_smile:

2 Likes

So does this work?
Any gudies for setting it up with say SkyrimVR?

Steam VR is causing me no end of issues and I would like to try VR games without it

VERY promising ! The potential is infinite ?

Tried with Elite Dangerous. Crashes with error -1007 on startup.

Can someone else give it a whirl in case I’m doing something wrong?

Would also love to get this working. I tried and got a crash.

yep tried but no luck getting this to work at all.
I don’t have any Oculous software installed. Not sure if its needed, no luck asking on their discord either.

you don’t need to rename the dll, like pcars (and dirt rally, thanks to Park for the finding), all you have to do is to create a file called steam_appid.txt on the game root folder, in case of project cars2 you should write this inside the txt:
378860\Othervr
then you add the exe to pitool directly using the import function and it will launch in oculus mode.
At least it has worked for project cars, i’m going to try it right now on project cars 2 too.
Oculus version does not need parallel projection so you can disable it and consequently hide hidden mask will work too, gaining a considerable boost in performance compared to the steamvr version.

2 Likes

Yes I have tried that with dirt rally already.

1 Like

i’m sure this trick will work for a lot of games, at least we can try out and see if we can disable pp, on assetto corsa oculus needs pp so it’s better using steamvr.
i’m updating the games sheet constantly while testing https://docs.google.com/spreadsheets/d/11ljKyF0eMgY3qqZWjVVBvI0brfv9IxocXjroYtJyTlY/edit#gid=0

1 Like

should have called it ReRift

1 Like

Rebumping thread as has some potential uses. Also be sure to checkout @neelrocker Oculus like Ipd setup.

2 Likes

How might this work with sksevr? do we add that exe to pitool instead of the skyfrimvr.exe?

Hi. I would like to ask You about one position in this list. Project Cars 2. I run it with SteamVR but without PP enabled it has double vision during the race.

Why on the PC2 row it is written that PP is No? Is it a mistake or You have some way to run it with SteamVR without PP and double vision problem?

Also I ran PC2 without SteamVR through Oculus but I started it from PiTool with steam_appid.txt. This does not require PP. I don’t know why but I don’t see many improvements in FPS comparing to SteamVR with PP.

in oculus mode without pp is a significant boost.

the ability to run without PP is with oculus mode, if you run in steam mode you’ll have double image there’s no other way, steamvr version needs PP

1 Like

Then why on row number 127 in your list it is written that PC2 run through SteamVR and both PP columns have value “No”?

Is this telling to set PP to OFF? Or I don’t interpret it correctly?