[Bug 38452] New: ETQW: Renders garbage in some places

[Bug 38452] New: ETQW: Renders garbage in some places

[bugzilla-daemon]

https://bugs.freedesktop.org/show_bug.cgi?id=38452

           Summary: ETQW: Renders garbage in some places
           Product: Mesa
           Version: git
          Platform: Other
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Drivers/Gallium/r600
        AssignedTo: dri-devel@lists.freedesktop.org
        ReportedBy: sa@whiz.se


Created an attachment (id=48141)
 --> (https://bugs.freedesktop.org/attachment.cgi?id=48141)
screenshot of bug

As mentioned in bug 35434 there is a glitch in the game ETQW where the screen
just renders garbage. It doesn't seem to be related to any settings in the game
and is only reproducible on some places in some of the maps.

The best description to reproduce the bug is the one given in bug 35434:
"I know now exactly where this is reproductible. For example, in "area
22" map, start with Strogg (soldier), you will land on the right of the Strogg
base, then just turn left (looking to the Cyclope), and there is artefact (or
now freeze&shake). I noted that watching the Cyclope on this map always results
in this behavior."

I have also provided an apitrace which makes it easy to reproduce the problem:
http://dl.dropbox.com/u/28577999/etqw.trace.7z  (51M)

System environment:
-- system architecture: 32-bit
-- Linux distribution: Debian unstable
-- GPU: REDWOOD
-- Model: XFX Radeon HD 5670 1GB
-- Display connector: DVI
-- xf86-video-ati: 6.14.2
-- xserver: 1.10.2
-- mesa: 2fe39b46e73aea37152777fe11d489e0b1bc3f92
-- drm: 2.4.25
-- kernel: 2.6.39.1

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #1 from Vadim <ptpzz@yandex.ru> 2011-06-21 13:15:53 PDT ---
Created an attachment (id=48255)
 View: https://bugs.freedesktop.org/attachment.cgi?id=48255
 Review: https://bugs.freedesktop.org/review?bug=38452&attachment=48255

[PATCH] mesa: fix range check in _mesa_validate_DrawElements

It's a bug in ETQW. With this patch mesa will ignore invalid calls instead of
rendering garbage, but it won't fix the real bug in the game.

The bug is related to index buffers and setting "r_useIndexBuffers" to 1 works
for me. If it doesn't help, then it's another bug or you probably need to
restart the game after changing that value.

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #2 from Sven Arvidsson <sa@whiz.se> 2011-06-22 05:22:52 PDT ---
On my system, the patch causes the display to simply stop updating when trying
to reproduce the bug. Look away from the area in the game causing the bug and
the screen starts updating again.

Are you sure you have diagnosed this correctly and that the bug is in the game?
Because none of the other Mesa drivers I have tried shows this behaviour (i965,
r300g).

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #3 from Vadim <ptpzz@yandex.ru> 2011-06-22 09:04:10 PDT ---
(In reply to comment #2)
> On my system, the patch causes the display to simply stop updating when trying
> to reproduce the bug. Look away from the area in the game causing the bug and
> the screen starts updating again.

It's exactly the expected behaviour.

> Are you sure you have diagnosed this correctly and that the bug is in the game?
> Because none of the other Mesa drivers I have tried shows this behaviour (i965,
> r300g).

Probably the game settings were adjusted by some auto-detect features in the
game while you have been testing with different drivers. Have you used the same
game installation with the same settings for testing? Also, have you tried
replaying your own trace file with different drivers?

Of course, it's possible that I've missed something. You could check it if you
are familiar with opengl. Open your trace with qapitrace and set filter:
Trace->Options->Only show the following events-> type "glDrawEle|glBindBuf" -
this will show only important events. Then select Edit->Go to call->674429. You
will see the following call: "glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER, 1024)".
So the game still uses index buffers for something and this call binds buffer
1024 as the index buffer. And then you could see that after binding the index
buffer there are calls to glDrawElements - they should do the rendering. When
the index buffer is bound, last parameter of glDrawElements is interpreted by
gl as the offset in the buffer. And when the index buffer is not bound, last
parameter should be the pointer to data in the memory. In the first
DrawElements call after binding the index buffer you could see the value
"0x9b46d720". Obviously, it is not valid value for the offset in the buffer
(buffer 1024 is ~2mb in size at this moment). It looks like a pointer, so it
seems the game engine is passing pointers to glDrawElements as if no index
buffer is bound. So the game should either unbind the index buffer or never
bind it at all before using DrawElements calls with pointers. And this also
explains why setting "r_useIndexBuffers" to 1 helps - if the game will always
use index buffers for rendering, then such situation will be impossible.

The bug is reproducible here with r600g (garbage or freeze), swrastg (crash),
and catalyst 11.5 (garbage or freeze). I'm using demo and you are using full
game, so some differences are possible, but afaics its not the case.

I think r_useIndexBuffers=0 was intended only for ancient low-end hw and was
tested with lowest settings only. If it is default on some configurations for
modern hw, then I think it is just autodetection fail in the game.

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #4 from Sven Arvidsson <sa@whiz.se> 2011-06-22 12:05:15 PDT ---
Indeed, I must have fouled up the settings for the game when I was trying
different drivers, as you said. Anyway, thanks for taking the time to explain
things!

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #5 from Benjamin Bellec <b.bellec@gmail.com> 2011-06-23 13:21:45 PDT ---
Thanks for your work, Vadim, it's really appreciated.

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #6 from Sven Arvidsson <sa@whiz.se> 2011-09-23 06:44:15 PDT ---
As far as I'm concerned, this bug can be closed, unless it should be kept open
to track the inclusion of the patch Vadim wrote?

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #7 from Benjamin Bellec <b.bellec@gmail.com> 2011-09-26 12:53:56 PDT ---
Yes I guess.

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #8 from almos <aaalmosss@gmail.com> 2011-10-17 10:27:51 PDT ---
(In reply to comment #3)

> The bug is reproducible here with r600g (garbage or freeze), swrastg (crash),
> and catalyst 11.5 (garbage or freeze). I'm using demo and you are using full
> game, so some differences are possible, but afaics its not the case.
> 
> I think r_useIndexBuffers=0 was intended only for ancient low-end hw and was
> tested with lowest settings only. If it is default on some configurations for
> modern hw, then I think it is just autodetection fail in the game.

I already reported this for r300g about a year ago, and the resolution was to
always make sure that r_useIndexBuffers=1 in your config. Otherwise, on r300g
it crashes with any detail setting. The game sets it to 0 whenever the gl
renderer string changes (AFAICT). See comment 85 on RadeonProgram.

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

--- Comment #9 from almos <aaalmosss@gmail.com> 2012-08-14 22:42:07 UTC ---
Can this be closed?

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[Bug 38452] ETQW: Renders garbage in some places

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https://bugs.freedesktop.org/show_bug.cgi?id=38452

Sven Arvidsson <sa@whiz.se> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #10 from Sven Arvidsson <sa@whiz.se> 2012-08-15 12:24:29 UTC ---
Yeah, let's consider this fixed.

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