Soft FP64 Patches For Intel Sandy Bridge Allow ARB_gpu_shader_fp64

[marcovtje]

That won't help for GL 4.0 on SNB (hence it's imho maybe a bit questionable, since that's usually the major reason why you even want FP64 capability, but OTOH why not...).
SNB is missing some other functionality required for GL 4.0 (the biggest ones probably being tesselation and at least some bits of ARB_gpu_shader5), and those can't be emulated in a meaningful way.

Afaik the geometry shader is also not entirely suitable. On Windows it only supports older shader model versions.

[eydee]

FP64 isn't too relevant for games and thus Linux gamers finding a GL4 game playable with SNB graphics could already override the extensions / GL level.

It isn't that easy. Some games don't like it. E.g. Serious Engine games (Sam, Talos) won't run when you do this. Steam application won't run when you do this. Fortunately they do support GL 3.x, so you don't have to. But what if they didn't support 3.x?

[wdb974]

Not holding my breath for anything beyond OpenGL 3.3 on my Sandy Bridge, but any extra extension shouldn't hurt to have.

[FireBurn]

Sandybridge doesn't have tessellation hardware as far as I can recall but I'm sure I saw one of the devs saying it might be possible to do something with transform feedback to implement some form of tessellation

[mczak]

That won't help for GL 4.0 on SNB (hence it's imho maybe a bit questionable, since that's usually the major reason why you even want FP64 capability, but OTOH why not...).
SNB is missing some other functionality required for GL 4.0 (the biggest ones probably being tesselation and at least some bits of ARB_gpu_shader5), and those can't be emulated in a meaningful way.

[phoronix]

Phoronix: Soft FP64 Patches For Intel Sandy Bridge Allow ARB_gpu_shader_fp64

Elie Tournier, the GSoC student developer who last year worked via GSoC on "soft" FP64 double-precision support for older GPUs lacking the hardware capabilities, has posted patches wiring up his soft implementation for Intel "Gen 6" (Sandy Bridge) graphics thereby allowing ARB_gpu_shader_fp64 support...

http://www.phoronix.com/scan.php?page=news_item&px=Mesa-SNB-Gen6-FP64-RFC