Intel Starts Landing Another OpenGL 4.3 Extension

[phoronix]

Phoronix: Intel Starts Landing Another OpenGL 4.3 Extension

Finally receiving some mainline treatment within Mesa this Sunday is the start of Chris Forbes' long work-in-progress patches concerning ARB_fragment_layer_viewport...

http://www.phoronix.com/vr.php?view=MTcyNzI

[CrvenaZvezda]

Sorry for my lack of knowlegde and understanding, but, will this benefit other drivers in any way? If so, how?

[kalrish]

Sorry for my lack of knowlegde and understanding, but, will this benefit other drivers in any way? If so, how?

Although Intel's drivers are based on DRI instead of Gallium, their work can benefit core Mesa, adding the necessary infrastructure. The patches seem to only add code to advertise the extension -as Michael reported, Chris Forbes' work is only being introduced-, but they could benefit other drivers, specially if the GLSL compiler is shared between them.

[xeekei]

Although Intel's drivers are based on DRI instead of Gallium, their work can benefit core Mesa, adding the necessary infrastructure. The patches seem to only add code to advertise the extension -as Michael reported, Chris Forbes' work is only being introduced-, but they could benefit other drivers, specially if the GLSL compiler is shared between them.

I've always wondered, what exactly is Gallium? And how does it differ from Mesa?

[zanny]

I've always wondered, what exactly is Gallium? And how does it differ from Mesa?

Mesa is an implementation of the OpenGL API against DRI and Gallium. Here is the path a GL call takes depending on your device:

Intel: GL Call -> Mesa libGL -> DRI -> intel-dri -> i915
AMD: GL Call -> Mesa libGL -> Gallium / DRI (depending on call) -> winsys on gallium -> ati-dri -> radeon

You can read the wiki article here: https://en.wikipedia.org/wiki/Mesa_%...er_graphics%29

If you want more clarification just ask.

[CrvenaZvezda]

Although Intel's drivers are based on DRI instead of Gallium, their work can benefit core Mesa, adding the necessary infrastructure. The patches seem to only add code to advertise the extension -as Michael reported, Chris Forbes' work is only being introduced-, but they could benefit other drivers, specially if the GLSL compiler is shared between them.

Thanks!

[xeekei]

Mesa is an implementation of the OpenGL API against DRI and Gallium. Here is the path a GL call takes depending on your device:

Intel: GL Call -> Mesa libGL -> DRI -> intel-dri -> i915
AMD: GL Call -> Mesa libGL -> Gallium / DRI (depending on call) -> winsys on gallium -> ati-dri -> radeon

You can read the wiki article here: https://en.wikipedia.org/wiki/Mesa_%...er_graphics%29

If you want more clarification just ask.

Then I guess I wonder what the difference between Gallium and DRI is. Are they competing? Or do they need each other?

[halfmanhalfamazing]

Where is GLSL 4.0 at?

These changes will end up in the Mesa 10.3 release later this summer, which could be known as Mesa 11.0 if there's OpenGL 4.0 compliance in time.

Is there any word on the state of progress for GLSL 4.0?

[bridgman]

Mesa is an implementation of the OpenGL API against DRI and Gallium. Here is the path a GL call takes depending on your device:

Intel: GL Call -> Mesa libGL -> DRI -> intel-dri -> i915
AMD: GL Call -> Mesa libGL -> Gallium / DRI (depending on call) -> winsys on gallium -> ati-dri -> radeon

You can read the wiki article here: https://en.wikipedia.org/wiki/Mesa_%...er_graphics%29

If you want more clarification just ask.

Calling the non-Gallium path "DRI" is probably obsolete at best. I think the intent of the Wikipedia diagram was to say "this is the interface that was used back in the DRI 1 days", but that ("classic Mesa") interface is still used today even with DRI 3. DRI is a separate interface used with both Gallium and non-Gallium paths.

I think the usual terminology is along the lines of :

- the Mesa stack has two major sections -- HW independent common code and HW-dependent "hardware layer" code
- there are two hardware layer interfaces -- "classic Mesa" and "Gallium3D", each with a set of functions and an IR for shaders
- Intel uses an enhanced "classic Mesa", passing GLSL IR rather than Mesa IR to the HW layer
- radeon and nouveau use Gallium3D, passing TGSI to the HW layer (except OpenCL which passes LLVM IR instead of TGSI)
- older drivers use classic Mesa and Mesa IR
- all the drivers use various versions of DRI
- each of the hardware layer interfaces includes software renderers - <I forget name> for classic Mesa and softpipe / llvmpipe for Gallium3D

The above may not be 100% correct either (I imagine Intel has changed more than just IR but haven't paid attention) but I think it's closer anyways

[bridgman]

Stupid 5 minute limit. 5 minutes and 30 seconds would be much better

I think the software renderer for classic mesa HWL might be called swrast.