[Mesa-dev] [PATCH 0/5] Gallium: Passing drirc options to create_screen() and fixing Rocket League

[Ilia Mirkin]

On Wed, Jun 21, 2017 at 9:58 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Tue, Jun 20, 2017 at 6:54 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> The first pipe_screen flag is a drirc option to fix incorrect grass
>> rendering in Rocket League for radeonsi. Rocket League expects DirectX
>> behavior for partial derivative computations after discard/kill, but
>> radeonsi implements the more efficient but stricter OpenGL behavior
>> and that will remain our default behavior. The new screen flag forces
>> radeonsi to use the DX behavior for that game.
>
> For those of us following along at home... can you provide a brief
> reminder of what the DX behavior is, and how does it differ from GL
> behavior? In case one might want to fix this for nouveau (if a fix is
> needed at all)...

>From what I gather, this is the difference between discard exiting
immediately in that thread and keeping going.

Does this make sense to be surfaced in gallium via a tgsi program
property? That way, e.g. a GL extension could be written to expose
that program property.

  -ilia