[Mesa-dev] sampler types in tgsi

Jose Fonseca jfonseca at vmware.com
Fri Nov 28 23:43:48 PST 2014

On 29/11/14 06:07, Roland Scheidegger wrote:
> Am 29.11.2014 um 06:12 schrieb Ilia Mirkin:
>> Hello,
>> It appears that the A3XX ISA (freedreno) requires the texture
>> instruction to properly specify its output type (or at least f32 vs
>> u32). Now I could stick this into a driver-local shader key, but it
>> seems unfortunate since in glsl, it knows whether it's an int or float
>> sampler.
>> Would there be any objections to being able to specify an int property
>> on the SAMP declaration? Or some alternate approach?
> Hmm I guess the return type of the sampler_view decl was intended for
> something along these lines (it's a d3d10-ism but not really used right
> now, and it is per channel too).

Right -- 

> If you make some return type in sampler
> this is thus not very nice as now you've got it both in sampler and
> sampler_view. Not sure what a good solution of that would be...

I think a good compromise would be to force separate declarations of 
sampler_view and sampler, like we need to do for D3D10 sample opcodes

   DCL SAMP[0]
   TEX OUT[1], IN[1], SAMP[0]

at least for the UINT resources.

I also think that eventually we should have TGSI to drop the opcodes 
that take combined sampler and sampler_views, have only the D3D10 like 
opcodes with seperate operands for sampler and sampler_view, and have a 
PIPE_CAP_SEPARATE just for those drivers that can handle the 
combination. But this can wait.


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