[Mesa-dev] [PATCH] softpipe: fix shadow sampling and remove nonsensical approximation of linear interpolation behavior for shadow samplers.

[Roland Scheidegger]

Am 14.04.2014 16:32, schrieb Janzing, Heinrich:
> Are you saying that the nearest neighbour sampling implementation is 
> still not entirely correct now?
No this is correct indeed.

 For the linear interpolation case I
> much prefer the current imperfect behavior over the previous 
> behavior, though a comment might still have been in order to 
> highlight the remaining work in that area. Sorry for not adding it.
Yes this ought to be much better (afaict this also is what some hw which
couldn't do shadow comparisons in the sampler itself has done some time
ago). I was really only missing the comment, but no biggie (the error is
easy to spot and notice what it actually is).

Roland



> Heinrich
> 
> -----Original Message----- From: Roland Scheidegger 
> [mailto:sroland at vmware.com] Sent: maandag 14 april 2014 16:20 To: 
> Janzing, Heinrich; mesa-dev at lists.freedesktop.org Subject: Re: 
> [Mesa-dev] [PATCH] softpipe: fix shadow sampling and remove 
> nonsensical approximation of linear interpolation behavior for
> shadow samplers.
> 
> Am 11.04.2014 09:14, schrieb Janzing, Heinrich:
>> Shadow sampling appeared to be fundamentally broken; fix in 
>> attachment.
>> 
> 
> This looks ok to me (I put in the comment about this not making
> sense in the first place...). It should be noted though and I'd have 
> preferred if a comment would still say that somewhere that even with 
> this the behavior isn't quite right neither (though arguably much 
> better) and the reason I didn't actually fix it at that time since
> it was a bit more complex, what will happen is that we'll do
> bilinear filter first, then replace with 0/1 depending on the
> filtered result. GL actually allows this but ideally you'd really
> exchange the values with 0/1 _before_ doing the bilinear filter.
> 
> Roland
>