SteamVR has a hidden configuration parameter which allows to enable supersampling for VR applications. With supersampling graphics are rendered in a higher resolution than the native one of the screen in the headset. Afterwards the image is down-sampled and antialiased. This generates a sharper image because – for example – small lines and other details have to be rendered completely before antialiasing. The downside is that this really raises the burden on the graphics card. Additionally, not all VR games support supersampling. Valve probably had a good reason to keep this configuration parameter hidden, so setting it manually might have negative consequences.
To enable supersampling in SteamVR, one has to edit a JSON formatted configuration file. It's a good idea to create a backup before doing so.
The configuration file named "steamvr.vrsetting" is located in the Steam configuration directory. On my computer it can be found under the following path:
C:\Programme (x86)\Steam\config
The file can be edited with any normal text editor.
Now the line "renderTargetMultiplier" has to be added to the "steamvr"-block. It is absolutely necessary to add a comma to the preceding line! In this example I had to add it after the value "#FFFFFF8E" for "playAreaColor". Otherwise, Steam will fail reading and parsing that file. The already existing entries in the block may vary.
"steamvr" : {
"allowReprojection" : true,
"background" : "...",
"basestationPowerManagement" : true,
"playAreaColor" : "#FFFFFF8E",
"renderTargetMultiplier" : 2.1
}The value for "renderTargetMultiplier" can be changed as you like. The higher the value, the better the graphics might be, but also the impact on the GPU.
I use a GeForce GTX 980 Ti and played a little bit around with the Space Pirate Trainer. It turned out that I can only use values below 2.0 with my setup, otherwise the game will start to stutter and the screen will flicker sometimes. But even with lower supersampling multiplier values, the text of the SteamVR interface looks a lot crisper than normally. This also applies to text in other applications and games. So I think supersampling in VR is a good thing as long as your graphics card can handle it.
Updates
17.09.2016
Obviously there was a bug in Steam which affected the interpretation of the renderTargetMultiplier, and which was fixed by a recent update:
"Fixed a case where numeric settings would get rounded to the nearest integer if the default value was an integer. This affected users who manually configured “renderTargetMultiplier”, which has a default value of 1."
Maybe I should give it another try. Then again some games like Space Pirate Trainer already support setting the value directly inside the application since the latest update.
