Major performance regression in the SteamVR plugin (affects all released games)

I submitted this to answer hub, but thought many people might want to see it here:

The engine does a hard coded check on the CRC of the hidden area mesh returned from SteamVR, and if it doesn’t match the hardcoded value, it skips generating a visible area mesh (used for speeding up post processing).

At some point the SteamVR API has started returning hidden area mesh with a different CRC, and so the UE4 SteamVR plugin now just doesn’t generate a visible area mesh at all, resulting in much slower (~15%) post processing.

I don’t know when SteamVR started returning that different mesh, but as soon as it did, every released UE4 game was affected because of this hardcoded CRC value.

Upvoted on answerhub. I’d like to hope they fix it soon, but has a strong doubts :frowning:

There is a pull request with a fix now: