XSFur will cause severe FPS issues or driver crashes in VR on newer AMD drivers

[FenrirVR]

XSFur will cause severe FPS issues or driver crashes on newer AMD drivers, everything over version 22.5.1 is effected, im running a 6800 XT but i know someone who has an 6700 type card who has the same issue. This problem only persists in VR using VRC in desktop mode is not effected.

[Xiexe]

Sounds like a classic case of AMD drivers being bad since the shader hasn't changed in awhile.

I don't own any AMD hardware to test on and don't plan on buying any unfortunately.

[FenrirVR]

I got feedback from some freinds who own nvidia hardware, also claim that a particular world using this shader for the carpet is very heavy on their system since quite a while being in VR:
https://vrchat.com/home/world/wrld_fac11e5f-1c73-4436-8936-a70b80961c5a

So even nvidia user seem to have a bit of trouble even though dont seem as bad as on AMD hardware. If you dont intend to fix it any plans on putting it out open source so maybe someone else can fix it ? Or at least stopping to sell it on Booth as it might cause some serious trouble for some users ?

[Xiexe]

I mean if that’s the case it sounds like really the person who made the world is possibly using some ridiculous settings despite the warnings to not crank everything and expect it to run just fine.

Likely you’re running into overdraw limitations, which can be fixed by lowering the layer count or by lowering the percentage of pixels the shader takes up on the screen.

Fur shaders are inherently expensive. They always will be. That could mean instability on particularly weak GPUs, GPUs with bad drivers, or just in general depending on what the setup is for the material. All current hardware struggles with overdraw.

Think about how many pixels are being rendered if it covers the entire screen, the worst case scenario. On a 4K monitor you’re rendering 8,300,000 pixels.

You’re doing all the lighting calculations for each of those.

Now imagine you have to do that 32 times, over and over for the same pixels because you have 32 fur layers. This is the limitation with fur shaders.

For reference, that’s 265,420,800 times you’d need to do lighting and whatever other calculations to get the way you want the shader to look.

Of course, that’s only if you do shell based fur, which is what my fur shader does.

It doesn’t matter what method you do or how well it’s optimized though, it will always be expensive if taken to the extreme especially (until even better hardware is eventually available)

The only option for “cheap” fur is to model hair cards, which isn’t going to give the look you’d want for a carpet.

[FenrirVR]

Well my friends have no idea when it started getting worse but they said it used to perform way better, I can say for my self its after driver version 22.5.1 if i downgrade to this driver version that particular world performs fine, and the creator does not seem to have used any insane settings.