Summary: | Input sample mask has unexpected values | ||
---|---|---|---|
Product: | Mesa | Reporter: | Józef Kucia <joseph.kucia> |
Component: | Drivers/Vulkan/intel | Assignee: | Intel 3D Bugs Mailing List <intel-3d-bugs> |
Status: | CLOSED NOTOURBUG | QA Contact: | Intel 3D Bugs Mailing List <intel-3d-bugs> |
Severity: | normal | ||
Priority: | medium | CC: | danylo.piliaiev, jason |
Version: | git | ||
Hardware: | Other | ||
OS: | All | ||
Whiteboard: | |||
i915 platform: | i915 features: | ||
Attachments: | resulting image on anv |
Description
Józef Kucia
2019-01-31 14:41:52 UTC
Created attachment 143510 [details]
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).
(In reply to Danylo from comment #1) > Created attachment 143510 [details] > 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 : https://gitlab.freedesktop.org/mesa/piglit/blob/master/tests/spec/arb_post_depth_coverage/multisampling.c#L75 I should have a closer look into the issue before reporting the bug. Thanks. |
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