Remove global -ffast-math flag, instead apply fast math to just color_helpers.cpp

[sharkautarch]

Should fix https://github.com/ValveSoftware/gamescope/issues/1493

[misyltoad]

I'd rather just have the pragma thing, rather than the denorms thing... We can come back to it if we want it.

[sharkautarch]

@Joshua-Ashton instead of turning on ftz/daz globally, I ended up using some intrinsics for x86 and aarch64 to just turn on ftz/daz inside ~~calcColorTransform~~ create_color_mgmt_luts, w/ the msrs being restored after returning from the function Let me know if this is ok, or just too complicated

[Exotic0015]

Can confirm this fixes #1493.

[sharkautarch]

Edited to remove the msr things as per misyl’s feedback

[bandithedoge]

This should also fix #1622.

[sharkautarch]

Slight edit to PR: reduced the scope of FAST_MATH_ON so that it no longer is applied to glm headers (except for the matrix headers, bc it's unlikely to be used outside of color_helpers.cpp), in case they are ever used outside of the color helpers stuff in the future

[fxzzi]

can also confirm that using this PR fixes the bluriness with gamescope, even at native resolutions. Is this going to be merged soon?

[sharkautarch]

Is this going to be merged soon?

I’ll check in with misyl on that soon Currently the higher priority PR is : https://github.com/ValveSoftware/gamescope/pull/1697

[fxzzi]

Hi, any news on this? Seems to have been left for a while and without this PR pretty much makes gamescope unusable for me

[sharkautarch]

Hi, any news on this? Seems to have been left for a while and without this PR pretty much makes gamescope unusable for me

I'll checkin with misyl/august

[sharkautarch]

@fxzzi So it turns out that unfortunately, the gamescope dev is on holiday until the 12th So I don’t think this PR will be able to get merged until then (unless something’s changed recently, there’s only one gamescope developer)