From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@freedesktop.org Subject: [Bug 93594] Flickering Shadows in The Talos Principle Date: Thu, 18 Feb 2016 01:17:29 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1192677768==" Return-path: Received: from culpepper.freedesktop.org (culpepper.freedesktop.org [131.252.210.165]) by gabe.freedesktop.org (Postfix) with ESMTP id DE4B66E2FF for ; Thu, 18 Feb 2016 01:17:29 +0000 (UTC) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============1192677768== Content-Type: multipart/alternative; boundary="14557582491.6B42.19428"; charset="UTF-8" --14557582491.6B42.19428 Date: Thu, 18 Feb 2016 01:17:29 +0000 MIME-Version: 1.0 Content-Type: text/plain https://bugs.freedesktop.org/show_bug.cgi?id=93594 --- Comment #14 from Roland Scheidegger --- (In reply to Marek Olšák from comment #13) > (In reply to Roland Scheidegger from comment #12) > > Due to d3d10 being different there, I wouldn't be surprised if other apps > > make the same mistake. > > For performance, it's better to execute KILL as soon as possible, because it > allows us to skip texture loads and possibly even input loads. Certainly, which is probably why it is undefined behavior in glsl. My guess is the d3d10 drivers will check dependency chains and see if the result may be needed later for derivatives, and if it is only kill whole quads immediately or something like that. Whereas in GL it would be the responsibility of the shader to do the actual kill only when the pixels aren't needed any longer for calculating derivatives (though I suppose that means it potentially wouldn't early discard whole quads neither). -- You are receiving this mail because: You are the assignee for the bug. --14557582491.6B42.19428 Date: Thu, 18 Feb 2016 01:17:29 +0000 MIME-Version: 1.0 Content-Type: text/html

Comment # 14 on bug 93594 from 
(In reply to Marek Olšák from comment #13)
> (In reply to Roland Scheidegger from comment #12)
> > Due to d3d10 being different there, I wouldn't be surprised if other apps
> > make the same mistake.
> 
> For performance, it's better to execute KILL as soon as possible, because it
> allows us to skip texture loads and possibly even input loads.

Certainly, which is probably why it is undefined behavior in glsl.
My guess is the d3d10 drivers will check dependency chains and see if the
result may be needed later for derivatives, and if it is only kill whole quads
immediately or something like that. Whereas in GL it would be the
responsibility of the shader to do the actual kill only when the pixels aren't
needed any longer for calculating derivatives (though I suppose that means it
potentially wouldn't early discard whole quads neither).

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  • You are the assignee for the bug.
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