RadeonSI Lands OpenGL 3.3 Compatibility Profile Support

[microcode]

The bad news is the good news is old news and the blocker for compatibility profiles was always lack of interest in open source community and the thought that this is more of a matter of incorrectly designed games than a driver problem

Sadly, while it is correct that this is a matter of incorrectly designed applications (mostly not games), it is also true that they weren't going to fix that by being incompatible with these applications. If anything, by disregarding compatibility profiles, they had sealed the fate for RadeonSI as a perpetual enthusiast/casual graphics driver stack. With compatibility profiles and a handful of obscure features, RadeonSI can start to make sense for "professional" applications (whose developers sometimes refuse to write against core profile despite the fact that it is actually very, very easy).

[andrei_me]

I wonder for those games that are using OpenGL 4.5 Compat mode, if they are using it by mistake, passing the wrong parameter at the context creation or they are really mixing functions from Compat and Core mode

[skyrrd]

What games are you talking about?

[nanonyme]

I wonder for those games that are using OpenGL 4.5 Compat mode, if they are using it by mistake, passing the wrong parameter at the context creation or they are really mixing functions from Compat and Core mode

I suspect former. One could probably ask but I suspect the game makers would be a bit embarassed by that mistake.

[Kano]

I really wonder why tesselation support is needed for OpenGL Compat 3.3. I thought this was an OpenGL 4 feature?

[smitty3268]

I wonder for those games that are using OpenGL 4.5 Compat mode, if they are using it by mistake, passing the wrong parameter at the context creation or they are really mixing functions from Compat and Core mode

It tends to fall into 2 camps:

1. Windows games that don't even support linux. These games are obviously targeting the AMD and Nvidia windows drivers that all support the compat mode, and see no reason to even think about bothering with anything else. WINE just passes through the same calls so it doesn't translate the game into core profile mode.

2. Old/bad ports that only focused on supporting the NVidia driver. They basically just targeted nvidia and decided everyone else was out of luck - possibly because other drivers on linux sucked at the time of the port, so you can't completely blame them. Again, in this case they just assumed compat mode was always there and didn't bother trying to do anything else.

In both cases, most of the time they really aren't using any compat features and could easily switch over to core if they wanted. But it takes time/effort to test and support the new code, if nothing else, which they simply can't be bothered with after the initial port was written. And it just never occurred to them during the initial port because it worked on the driver they were testing with.

In some cases, they really do use some old features, in which case it would be a bit more work to fix up.

[smitty3268]

I really wonder why tesselation support is needed for OpenGL Compat 3.3. I thought this was an OpenGL 4 feature?

It is. I think the change here that enabled 3.3 was only the geometry shaders, but they went ahead and did tessellation as well because it was right there next to the same code and needed the same change. 4.0 can't be enabled yet because of other stuff that's still missing.

[soulsource]

Sadly, while it is correct that this is a matter of incorrectly designed applications (mostly not games), it is also true that they weren't going to fix that by being incompatible with these applications. If anything, by disregarding compatibility profiles, they had sealed the fate for RadeonSI as a perpetual enthusiast/casual graphics driver stack. With compatibility profiles and a handful of obscure features, RadeonSI can start to make sense for "professional" applications (whose developers sometimes refuse to write against core profile despite the fact that it is actually very, very easy).

Not writing against a core profile is a guaranteed way to shoot your own foot, imho. Those functions were deprecated for a reason...

[VikingGe]

Those functions were deprecated for a reason...

Yeah, but The Industry™ doesn't care. They care about adding new features to their 25 year old code base without having to touch any of that rotting garbage. Just look at Adobe.

I don't really mind if Mesa adds support for it, as long as it has no negative impact on the core profile implementation. RadeonSI in particular should be mostly feature-complete by now and performance in general is great as well, so it't not like crucial features and optimizations are getting delayed because of it.

[geearf]

Is this enough for Cemu?

Does this help with any native game or do they need 4+?