[Mesa-dev] [PATCH] mesa/st: swap order of clear() and clear_with_quad()

[Rob Clark]

On Wed, Nov 14, 2018 at 10:13 AM Marek Olšák <maraeo at gmail.com> wrote:
>
>
>
> On Wed, Nov 14, 2018, 7:54 AM Rob Clark <robdclark at gmail.com wrote:
>>
>> On Tue, Nov 13, 2018 at 9:54 PM Marek Olšák <maraeo at gmail.com> wrote:
>> >
>> >
>> >
>> > On Tue, Nov 13, 2018, 6:00 PM Rob Clark <robdclark at gmail.com wrote:
>> >>
>> >> On Tue, Nov 13, 2018 at 5:25 PM Eric Anholt <eric at anholt.net> wrote:
>> >> >
>> >> > Rob Clark <robdclark at gmail.com> writes:
>> >> >
>> >> > > If we can't clear all the buffers with pctx->clear() (say, for example,
>> >> > > because of ColorMask), push the buffers we *can* clear with pctx->clear()
>> >> > > first.  Tilers want to see clears coming before draws to enable fast-
>> >> > > paths, and clearing one of the attachments with a quad-draw first
>> >> > > confuses that logic.
>> >> >
>> >> > Oh, nice!
>> >> >
>> >> > Reviewed-by: Eric Anholt <eric at anholt.net>
>> >> >
>> >> > Though it feels pretty silly that the ->clear() caller needs a
>> >> > clear_with_quad implementation when the ->clear() implementation in the
>> >> > driver also needs a clear_with_quad implementation for non-fast-cleared
>> >> > buffers.  :/
>> >>
>> >> hmm, so perhaps one easy option is to change pctx->clear() to return a
>> >> boolean, so driver can return false to ask the state tracker to do a
>> >
>> >
>> > Ideally all pipe context functions should always return void to allow gallium multithreading.
>>
>> Hmm, that is a bit awkward..  and a pipe cap is a bit restrictive, ie.
>> say you can fast-clear only certain color formats, or other weird
>> combination of restrictions.
>>
>> I suppose a pctx->can_do_clear(..) which isn't multithreaded would be
>> a bit more flexible than pipe caps.
>
>
> can_do_clear(..) should be in pipe_screen. I wouldn't like to have context functions that return a value.

that means we'd have to pass it framebuffer state, scissor state, and
colormask.. which is a bit annoying and less of a trivial change to
allow drivers to delete some code..

BR,
-R

> Marek
>
>>
>> > A pipe cap for colormasked and scissored clears would be better.
>> >
>> >
>> >> clear_with_quad()..  maybe that would be a first step towards allowing
>> >> driver to handle clears w/ colormask and possibly scissor (although
>> >> for the later, plus
>> >> glInvalidateFramebuffer()/glInvalidateSubFramebuffer(), I was thinking
>> >> of pctx->invalidate_surface()/pctx->invalidate_sub_surface())
>> >
>> >
>> > Pipe context already contains an invalidate function.
>>
>> yeah, but it is at the level of pipe_resource, which isn't really what
>> you want if only a certain level/layer of a resource is invalidated.
>>
>> I'm still unsure about how I want to track this in the driver, the
>> ideal case would be to track it in fd_surface, except that surfaces
>> tend to be created transiently.  Still for glInvalidateFramebuffer()
>> and friends, having an pctx->invalidate_surface() seems like the
>> cleaner API.
>>
>> BR,
>> -R
>>
>> >
>> > Marek
>> >
>> >>
>> >> But either way, I guess this patch is a simple stop-gap solution.
>> >>
>> >> BR,
>> >> -R
>> >> _______________________________________________
>> >> mesa-dev mailing list
>> >> mesa-dev at lists.freedesktop.org
>> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev