Bug 88642

Summary: Trilinear sampling on cubemap wrongly sampled at the border of rasterized triangle on HAWAII
Product: Mesa Reporter: vincent <vljn>
Component: Drivers/Gallium/radeonsiAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED FIXED QA Contact: Default DRI bug account <dri-devel>
Severity: normal    
Priority: medium CC: smoki00790
Version: 10.4   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: Test case
Diagonal line

Description vincent 2015-01-20 22:52:43 UTC
Created attachment 112566 [details]
Test case

Hi,

on a R290X with a fresh fedora 21 install (Mesa 10.4.1) a fragment shader sampling a cubemap texture with trilinear filtering is not correctly executed on the edge of rasterized triangles.

I've included a patch against piglit that display the behaviour. On my system the test display a small orange diagonal line on top of the color pattern. 
(the test doesn't check result atm)

I think it's related to some quad pattern : in my app that has a depth buffer the line follows the edge of the geometry.
Comment 1 vincent 2015-01-20 22:56:12 UTC
Created attachment 112567 [details]
Diagonal line
Comment 2 Michel Dänzer 2015-01-21 04:10:07 UTC
That kind of artifacts is usually due to whole quad mode not being enabled when it should be. The LLVM patch http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150119/254035.html fixes it.
Comment 3 smoki 2015-01-26 15:07:41 UTC
*** Bug 87518 has been marked as a duplicate of this bug. ***
Comment 4 Michel Dänzer 2015-02-06 03:09:16 UTC
Author: daenzer
Date: Thu Feb  5 20:51:20 2015
New Revision: 228372

URL: http://llvm.org/viewvc/llvm-project?rev=228372&view=rev
Log:
R600/SI: Also enable WQM for image opcodes which calculate LOD v3

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