[Mesa-dev] gallium and ARB_texture_query_levels

[Chia-I Wu]

On Mon, Feb 24, 2014 at 5:03 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Mon, Feb 24, 2014 at 3:38 AM, Dave Airlie <airlied at gmail.com> wrote:
>> I've taken a quick look at ARB_texture_query_levels,
>>
>> and the HW generally seems to implement this by returning it in the W
>> channel of RESINFO, which would map to the TXQ instruction,
>>
>> So my initial implementation added a LEVQ TGSI instruction but I do
>> think this isn't representative of the hw and I should add it to TXQ
>> with maybe a CAP to say it supports levels.
>
> Is there even hw that supports TXQ but doesn't return the levels info
> in W? A quick grep suggests that llvmpipe, ilo, nv50+, r600+ support
> TXQ. I assume that llvmpipe shouldn't be an issue, nv50+ has it, and I
> believe you've indicated that r600+ has it. So the question is whether
> ilo can do it or not... looking at the i965 code, it seems like ir_txs
> and ir_query_levels are handled with the same shader opcode. And
> there's a comment "/* # levels is in .w */"...
Yes, GENs supported by ilo have it in W of RESINFO.

>
>   -ilia
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