[Bug 93594] Flickering Shadows in The Talos Principle

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=93594

Marek Olšák <maraeo at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #27 from Marek Olšák <maraeo at gmail.com> ---
(In reply to EoD from comment #26)
> (In reply to Marek Olšák from comment #25)
> > (In reply to Christoph Haag from comment #24)
> > > Well, not sure what exactly we are talking about. The quick flickering that
> > > made it completely unplaybable is gone.
> > > 
> > > I'm not sure how the shadows are supposed to look like. I tried
> > > https://cgit.freedesktop.org/~nh/llvm/log/?h=images and that's what it looks
> > > like
> > > https://www.youtube.com/watch?v=DzkV_BHXzuU
> > > (damn, gstreamer recording + vaapi encoding is stuttering a lot again)
> > 
> > Looks good. What fixed it? The LLVM patch or game update?
> 
> The video shows from Christoph Haag shows those "minor flickerings" we were
> talking about. Those flickers also are in the D3D11 and Vulkan version of
> the game, so it's not an issue on mesa's side.

It's not an issue. It's normal behavior. It's a trait of the shadow mapping
technique and it happens when the shadow map isn't large enough. AFAIK, shadow
mapping is the best way to do soft shadows, but the technique alone can create
a lot of artifacts and what you've seen there aren't even the worst ones. Game
developers usually spend as much time implementing shadow mapping as they spend
on attempts to hide its flaws. See the images here for some extreme examples of
what is "normal" with the technique:
https://takinginitiative.wordpress.com/2011/05/25/directx10-tutorial-10-shadow-mapping-part-2/

> 
> For me, the flickering disappeared after updating the game, not llvm. Do you
> want us to test the old game version with those llvm changes?

No, we can close this as fixed by the game developer. Thanks.

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