The Student Working On "Soft" FP64 Support Is Good News For Older GPUs

[phoronix]

Phoronix: The Student Working On "Soft" FP64 Support Is Good News For Older GPUs

This summer the student developer Elie Tournier participated in Google Summer of Code to develop a "soft" double-precision floating-point library for Mesa. While GSoC is past, it appears he is committed to seeing this library through and getting into Mesa. With potential soft/emulated ARB_gpu_shader_fp64 support, this could be good news for those GPUs lacking real double precision support...

http://www.phoronix.com/scan.php?page=news_item&px=Soft-FP64-GPU-Work-XDC2016

[eydee]

Good news. While forcing OGL version works most of the time, if you run into an unrelated bug and want to take a closer look, a forced context can be annoying, as things like apitrace don't work properly with them. Having that library just for this reason is a good enough reason in my opinion. Speed doesn't matter, there are still 0 games using fp64.

[LinuxID10T]

This is great news for anyone that owns any Terascale 2 or 3 hardware. Being stuck on OpenGL 3.3 blows when the hardware is capable of OpenGL 4.5 other than the double precision support (which nothing uses.) Once you force OpenGL 4.1 support the hardware is still pretty capable. I was running Metro 2033 Redux and it was playable at medium settings.

[TumultuousUnicorn]

Good new. My HD 6870 stucks on OpenGL 3.3 too. I hope it will be merged in Mesa.
Bon travail Elie, merci.

[M@yeulC]

Great project. Hopefully games won't use this feature too much anyway (here and there would be OK, but I am afraid the performance would tank if they made heavy use of FP64 — true for almost any GPU, but especially in this case where FP64 is emulated).

Could someone explain the line

!!!bits32 high, low;

to me? Or is it again some preprocessor magic?

I am also a bit curious: will this be directly implemented in mesa, thus automatically usable by every driver that needs it? If so, that's even more impressive.

Good new. My HD 6870 stucks on OpenGL 3.3 too. I hope it will be merged in Mesa.
Bon travail Elie, merci.

Pareil

[Hi-Angel]

Nice, I've got such GPU. For I faking a higher version, SpaceEngine with Wine crashes for me, supposedly because of this extension (idk how to debug whether it tries this extension, but given how much work SpaceEngine does, it is very likely that it makes use of this extension).

[smitty3268]

I am also a bit curious: will this be directly implemented in mesa, thus automatically usable by every driver that needs it? If so, that's even more impressive.

I believe that's the plan. The GLSL parser can automatically inline the 64-bit emulation code when it detects that it needs to, and then the driver will never see any fp64 operations that it needs to handle.

It requires GL3, though, so really old hardware won't be supported.

[Adarion]

Quick! Upstream it! That will bring a lot of elderly cards to shine.
I count Google as "evil" (yeah, don't be evil...) for a lot of things, but on the other hand their GSoC installation (among a few other techy things) is a marvellous thing.
Thanks to Elie and his tutors, this might be some work that yields a lot of palpable positive results.

[wdb974]

That's awesome! That's yet another reason to buy and recommand AMD GPUs under Linux.

Merci et beau boulot !

[DeepDayze]

I am sure this library can also be useful for nouveau too, to help provide GL4 support for those NV cards that don't have hardware FP64 support. This will help certain older cards work with GL4 when it comes time.