[Piglit] [PATCH] texture-integer: use usampler/uint value

[Ilia Mirkin]

On Mon, Nov 23, 2015 at 4:34 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Mon, Nov 23, 2015 at 4:17 PM, Ian Romanick <idr at freedesktop.org> wrote:
>> On 11/20/2015 09:24 PM, Ilia Mirkin wrote:
>>> All of the random values are positive. Mixing uint texture with isampler
>>> is not allowed, and happens to cause problems for freedreno. Using uint
>>> works.
>>
>> I guess I'm confused what the actual problem is.  The test previously
>> used isampler with ivec4.  Did that work with freedreno?
>
> Nope, that's why I'm changing it :)
>
>>  Is the UINT
>> vs. INT base type of the texture the problem?
>
> Yes, it appears so. Adreno a3xx/a4xx has instructions like
>
> sam (u32)result, coords
> sam (s32)result, coords
>
> And it *actually* converts. For example if you have an int texture
> format, and do
>
> sam (f32)result, coords
>
> then the result will contain floatified integers. All this leads to it
> being really sensitive to mismatches between sampler type in the
> shader and the declared texture format. My recollection is that such
> mismatches result in undefined behavior, so what the hardware is doing
> is "OK". Except then the tests fail.
>
> A proper fix would optionally use an int or uint sampler, but... meh.
>
>>
>> In other news... piglit's coverage of integer samplers is *pathetic*.
>> I grepped for all uses of isampler or usampler.  The second grep just
>> filters out the compiler tests.
>
> And almost none that test rendering.

By the way, an updated version of this patch makes an identical change for

tests/spec/ext_texture_integer/texture-integer-glsl130.c:
"uniform isampler2D tex; \n"

I never sent it since I assumed that nobody would look at it.

  -ilia