[Mesa-dev] [PATCH] radeonsi: Fix blending using destination alpha factor but non-alpha destination

Marek Olšák maraeo at gmail.com
Tue Feb 19 06:48:46 PST 2013


On Tue, Feb 19, 2013 at 3:28 PM, Michel Dänzer <michel at daenzer.net> wrote:
> On Die, 2013-02-19 at 14:04 +0100, Marek Olšák wrote:
>> On Tue, Feb 19, 2013 at 11:02 AM, Michel Dänzer <michel at daenzer.net> wrote:
>> >
>> > Really, what I don't understand is why r600g doesn't seem affected by
>> > this... at least on my RS880 it's passing the piglit tests this change
>> > fixes with radeonsi. So maybe I'm just missing some magic bit for
>> > radeonsi.
>>
>> RGB formats do fail fbo-blending-formats with r600g/redwood here.
>
> Okay.
>
>
>> However the alpha channel can sometimes contain 1 in memory even if
>> the format is RGBX. Off the top of my head, glClear, glTex[Sub]Image,
>> glCopyTex[Sub]Image always set alpha to 1.
>
> Well, but they shouldn't for these formats. :) The memory corresponding
> to X* channels should remain unchanged. I'm working on a separate patch
> for that for radeonsi.

I think the only way you could do that is to set the colormask to RGB.
Doesn't it have a negative effect on performance if some channels are
masked out?

Marek


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