On 12.10.2017 18:55, Emil Velikov wrote:
Hi Nicolai,
On 11 September 2017 at 16:11, Nicolai Hähnle <[email protected]> wrote:
From: Nicolai Hähnle <[email protected]>
The GLSL rules for interpolateAtSample are unfortunate:
"Returns the value of the input interpolant variable at
the location of sample number sample. If
multisample buffers are not available, the input
variable will be evaluated at the center of the pixel.
If sample sample does not exist, the position used to
interpolate the input variable is undefined."
This fix will fallback to monolithic shader compilation when
interpolateAtSample is used without multisampling.
One alternative would be to always upload 16 sample positions,
filling the buffer up with repetition when the actual number of
samples is less, and then ANDing the sample ID with 0xf. However,
that punishes all well-behaving users of interpolateAtSample,
when in reality, only conformance tests should be affected by
the issue.
Fixes
dEQP-GLES31.functional.shaders.multisample_interpolation.interpolate_at_sample.non_multisample_buffer.*
---
Going through the lists, shows that this has landed without the stable tag.
Normally that's considered as self-rejecting the patch.
Is that really the case here or we want to pick it up?
Hmm, this may have happened because only one patch in the series had the
tag?
To be honest, this isn't a high impact change so we can just drop it to
be on the safe side.
Cheers,
Nicolai
Thanks
Emil
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