Developers Are Still Working On OpenGL 4.x For Intel Haswell / Ivy Bridge

[duby229]

I didn't see any GCN cards that don't support DP. All the ones that had N/A were Terascale. Did I miss something?

I didn't look at the architecture column. I've been under the wrong impression for a while now. Thanks for pointing that out.

[gsedej]

@ intel devs: what OpenGL version could Ivy/Haswell without "software emulation"? Are there any features hw missing in gen7 vs gen8 (and gen9?) except fp64?
(e.g. Sandy does not have hw for tessellation so it could not reach 4.x)

[LinAGKar]

Here's a question: *Why* isn't fp64 used anywhere? The functionality it provides simply not that useful? Some specific gotcha in the design of the extension making it really difficult to actually use it in practice? What?

Nvidia and AMD cripples the fp64 performance on their consumer cards (not sure about Intel), and even if they didn't it could only get half the performance of fp32. In fact now they're getting fp16 to increase performance.

[duby229]

Nvidia and AMD cripples the fp64 performance on their consumer cards (not sure about Intel), and even if they didn't it could only get half the performance of fp32. In fact now they're getting fp16 to increase performance.

Well, to be fair I know I read a few places that there are compute scenario's that it can decrease overall latecy. But OpenGL just isn't ideal for those types of scenarios. It was added as an extension, but I don't think it was used anywhere. At least that's what I think the current situation is roughly.

[smitty3268]

@ intel devs: what OpenGL version could Ivy/Haswell without "software emulation"? Are there any features hw missing in gen7 vs gen8 (and gen9?) except fp64?
(e.g. Sandy does not have hw for tessellation so it could not reach 4.x)

Well, even fp64 is done in hardware and not falling back to the cpu - it's just that they have to do a ton of workarounds and using the hardware in ways it wasn't necessarily meant to.

I think stencil texturing (part of GL4.3) and query buffer object (in 4.4) are both similar in that they don't really work straightforwardly but can be hacked in. QBO is supported in haswell, so that one's only Ivy that needs work. Beyond that i think they have full GL 4.5 support, and probably will for the upcoming 4.6 as well.