[Bug 97002] dEQP-GLES3.functional.shaders.derivate.dfdx.fbo_float.vec2_highp fails

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=97002

--- Comment #7 from xinghua <xinghua.cao at intel.com> ---
We had find an issue when porting from the native code to webgl code,
https://github.com/KhronosGroup/WebGL/pull/1931. After correcting it, we found
that this issue passed on chrome.
And we had debugged why it passed on chrome and failed on native code, the root
cause is interpolation value range is different between webgl and native, but
the dfdx value is nearly same. For example, dfdx value of the same pixel R
channel,
Native:
interpolation value range: [0.84646081924438477 0.84647130966186523]
dfdx value: 0.846460342 does not be in range, so fail.

WebGL:
interpolation value range: [0.846458911895752 0.8464700281620026]
dfdx value: 0.8464603424072266 does be in range, so pass.

It seems that the range computed by CPU(native) and JS(WebGL) is different, We
suspect that the range computed by JS(64-bits) is more precise, so it is
reasonable that passes on WebGL. I hope the info is useful for you. Thank you.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-3d-bugs/attachments/20160726/d46fc4c8/attachment.html>