<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED NOTOURBUG - Input sample mask has unexpected values" href="https://bugs.freedesktop.org/show_bug.cgi?id=109519#c2">Comment # 2</a> on <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED NOTOURBUG - Input sample mask has unexpected values" href="https://bugs.freedesktop.org/show_bug.cgi?id=109519">bug 109519</a> from <a class="email" href="mailto:lionel.g.landwerlin@linux.intel.com" title="Lionel Landwerlin <lionel.g.landwerlin@linux.intel.com>"> Lionel Landwerlin</a> <pre>(In reply to Danylo from <a href="show_bug.cgi?id=109519#c1">comment #1</a>) > Created <a href="attachment.cgi?id=143510" name="attach_143510" title="resulting image on anv">attachment 143510</a> <a href="attachment.cgi?id=143510&action=edit" title="resulting image on anv">[details]</a> > resulting image on anv > > Hi, sorry for the delay. > > I checked an output of the test in RenderDoc and saw this (see attachment). > There is a diagonal of pixels having a *wrong* mask. > > It is happening because this test draws a big triangle which covers the > whole render area and this triangle is being clipped which divides it and > creates new geometry. > > So on this diagonal there are two fragments per one pixel and to get the > right coverage you should add their coverages together. > > e.g. you can achieve this by having ssbo and atomic adding sample mask to > the corresponding fragment's position (suggested by Lionel on irc). Here is how we did it for a post depth coverage test : <a href="https://gitlab.freedesktop.org/mesa/piglit/blob/master/tests/spec/arb_post_depth_coverage/multisampling.c#L75">https://gitlab.freedesktop.org/mesa/piglit/blob/master/tests/spec/arb_post_depth_coverage/multisampling.c#L75</a></pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>