[Bug 18993] New: Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Summary: Shadows and selection circles z-fight in World of
                    Warcraft
           Product: Wine
           Version: 1.1.23
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: directx-d3d
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

The lowest-setting shadows and selection circles in World of Warcraft do
z-fight with the ground. This is not a regression afaik, at least I haven't
seen an other behaviour yet.

As I was testing if the patch attached to Bug
#14174(http://bugs.winehq.org/show_bug.cgi?id=14174) causes problems in other
games, I noticed that the same patch does almost fix the problem in World of
Warcraft. I modified it a bit so it entirely fixes that z-fighting, but now it
doesn't fix the bug mentioned in report #14174.

As I don't really understand why its causing that, someone with enough
knowledge should investigate in it. I will attach the modified patch, allowing
to render lowest-settings shadows and selection circles correctly.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #1 from Lisa Denia   2009-06-18 20:29:59 ---
Created an attachment (id=21885)
 --> (http://bugs.winehq.org/attachment.cgi?id=21885)
Workaround enabling correct rendering of selection circles and shadows in World
of Warcraft

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Dorek Biglari  changed:

What    |Removed                     |Added
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                 CC|                            |[e-mail]

--- Comment #2 from Dorek Biglari   2009-12-25 03:11:01 ---
The problem is due to the undocumented (or rather incorrectly documented)
depthbias feature in direct3d. This site http://aras-p.info/blog/tags/d3d/
explains the differences between resolving z-fighting conflicts in direct3d and
opengl.  The place we need to apply the patch is in dlls/wined3d/state.c, in
the state_depthbias function on the line with the call to glPolygonOffset. 
Basically, you need to make the number that d3d is sending to opengl larger. 
This works on my configuration (NVidia 6xxx, 24 bit depth buffer, which I think
is pretty common):

static void state_depthbias(DWORD state, IWineD3DStateBlockImpl *stateblock,
struct wined3d_context *context)
{
    union {
        DWORD d;
        float f;
    } tmpvalue;

if(stateblock->renderState[WINED3DRS_SLOPESCALEDEPTHBIAS] ||
       stateblock->renderState[WINED3DRS_DEPTHBIAS]) {
        tmpvalue.d = stateblock->renderState[WINED3DRS_SLOPESCALEDEPTHBIAS];
        glEnable(GL_POLYGON_OFFSET_FILL);
        checkGLcall("glEnable(GL_POLYGON_OFFSET_FILL)");
        glPolygonOffset(tmpvalue.f/(2.0*4.8e-7),
(*((float*)&stateblock->renderState[WINED3DRS_DEPTHBIAS]))/(2.0*4.8e-7));  /*
Changed to fix z-fighting in WoW */
        checkGLcall("glPolygonOffset(...)");
    } else {
        glDisable(GL_POLYGON_OFFSET_FILL);
        checkGLcall("glDisable(GL_POLYGON_OFFSET_FILL)");
    }
}

I don't know what the proper procedure is for submitting this, hopefully
somebody will see it.  I'm currently using it and it works great.  It may need
to be tweaked with a different number for 16 bit depth buffers.  This is my
first comment here as I usually have just been a wine user, and just decided to
start getting into the code.  Let me know if this works for anyone else.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #3 from Vitaliy Margolen   2009-12-26 11:49:21 ---
(In reply to comment #2)
http://wiki.winehq.org/SubmittingPatches

In short - use git, make a patch, send it to [e-mail]

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #4 from Austin English   2009-12-26 19:32:39 ---
Sent it for you:
http://www.winehq.org/pipermail/wine-patches/2009-December/083221.html

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #5 from Henri Verbeet   2009-12-27 05:57:13 ---
Created an attachment (id=25417)
 --> (http://bugs.winehq.org/attachment.cgi?id=25417)
patch

(In reply to comment #2)
>     glPolygonOffset(tmpvalue.f/(2.0*4.8e-7),
>
> (*((float*)&stateblock->renderState[WINED3DRS_DEPTHBIAS]))/(2.0*4.8e-7));  /*
> Changed to fix z-fighting in WoW */

That doesn't look right to me, how does the attached patch work?

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #6 from Dorek Biglari   2009-12-30 02:11:22 ---
It scales the depth bias value to be in the correct range. I know it works on
my hardware, an NVidia 6xxx running World of Warcraft in with a 24 bit depth
buffer, but I'd like to know if it works on all configurations, or if it helps
other apps. The number I divided by I got from the website:
http://aras-p.info/blog/2008/06/12/depth-bias-and-the-power-of-deceiving-you...

The author is discussing a cross platform app he's writing using OpenGL and
Direct3d.  The Direct3d users were complaining about zfighting.  I'll quote the
pertinent parts:

"How do you apply depth bias in OpenGL? Enable GL_POLYGON_OFFSET_FILL and set
glPolygonOffset to something like -1, -1. This works.

How do you apply depth bias in Direct3D 9? Conceptually, you do the same. There
are DEPTHBIAS and SLOPESCALEDEPTHBIAS render states that do just that. And so
we did use them.

And people complained about funky results on Windows."

He then goes on to state that he thought it was because people were using
terrible near/far planes, which is what I would think too.  And I think thats
probably why Lisa's patch also seems to correct the problem, because its
messing with the projection.  But the guy hits on an issue I have run into with
Direct3D before, that is that the documentation on the depth bias is wrong.

Continuing to quote from him:

"First, depth bias documentation on Direct3D is wrong. Depth bias is not in
0..16 range, it is in 0..1 range which corresponds to entire range of depth
buffer."

...

"So yeah, the proper multiplier for depth bias on Direct3D with 24 bit depth
buffer should be not 1.0/65535.0, but something like 1.0/(2^24-1). Except that
this value is really small, so something like 4.8e-7 should be used instead
(see Lengyel’s GDC2007 talk). Oh, but for some reason it’s not really enough in
practice, so something like 2.0*4.8e-7 should be used instead (tested so far on
GeForce 8600, Radeon HD 3850, Radeon 9600, Intel 945, reference rasterizer).
Oh, and the same value should be used even when a 16 bit depth buffer is used;
using 1.0/65535.0 multiplier with 16 bit depth buffer produces way too large
bias."

I've been running Wow and wine with this patch and it fixes the problem and I
have not noticed any side effects.  Out of curiosity, why do you think it looks
incorrect, Henri? If I am wrong here I would like to know. I assume that you
have seen the z-fighting that Lisa reported.  Let me know your thoughts.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #7 from Henri Verbeet   2009-12-30 03:20:01 ---
(In reply to comment #6)
> I've been running Wow and wine with this patch and it fixes the problem and I
> have not noticed any side effects.  Out of curiosity, why do you think it looks
> incorrect, Henri? If I am wrong here I would like to know. I assume that you
> have seen the z-fighting that Lisa reported.  Let me know your thoughts.

It makes sense to scale the WINED3DRS_DEPTHBIAS value if the value is specified
in normalized depth coordinates for D3D. However, WINED3DRS_SLOPESCALEDEPTHBIAS
is a scaling factor for the depth slope, so I don't think it makes sense to
scale that one.

My patch is almost the same as yours, but doesn't scale
WINED3DRS_SLOPESCALEDEPTHBIAS. It also uses 1e6f instead of 9.6e7f for the
WINED3DRS_DEPTHBIAS scaling factor, but I think that with the exact scaling
factor being device and driver dependant that shouldn't make much of a
difference. 9.6e7f corresponds with 1/2^20, I guess, but it's not an exact
representation anyway.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #8 from Dorek Biglari   2009-12-30 06:45:29 ---
Ah! Good point, Henri. I didn't know if scaling WINED3DRS_SLOPESCALEDEPTHBIAS
was necessary or not.  Also, as for the actual scaling value, that sounds good
too.  As long as whatever value used works in most circumstances, I think thats
good.  Thanks for pointing that out to me.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Thomas Venieris  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1

--- Comment #9 from Thomas Venieris   2010-01-01 11:27:28 ---
*** This bug has been confirmed by popular vote. ***

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Thomas Venieris  changed:

What    |Removed                     |Added
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                 CC|                            |[e-mail]

--- Comment #10 from Thomas Venieris   2010-01-01 11:29:07 ---
Just to confirm the problem on:
Debian x86_64 testing, wine 1.1.35 (compiled from source).
The patch posted here solves the problem for me.

Best regards,

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

--- Comment #11 from Henri Verbeet   2010-01-04 13:37:01 ---
Should be fixed by 2c0edb94e3da37a736b73f1a647bd3c9863f2608.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Jukka Tastula  changed:

What    |Removed                     |Added
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                 CC|                            |[e-mail]

--- Comment #12 from Jukka Tastula   2010-01-28 16:57:40 ---
Target circles and also projected textures are looking good now.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Dan Kegel  changed:

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                 CC|                            |[e-mail]

--- Comment #13 from Dan Kegel   2010-03-07 00:46:34 ---
Can we close this, then?

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Jerome Leclanche  changed:

What    |Removed                     |Added
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                 CC|                            |[e-mail]

--- Comment #14 from Jerome Leclanche   2010-05-13 05:44:59 ---
(In reply to comment #13)
> Can we close this, then?

Yes.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Dmitry Timoshkov  changed:

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

--- Comment #15 from Dmitry Timoshkov   2010-05-13 06:22:05 ---
Reported fixed.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Alexandre Julliard  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #16 from Alexandre Julliard   2010-05-21 14:39:24 ---
Closing bugs fixed in 1.2-rc1.

[Bug 18993] Shadows and selection circles z-fight in World of Warcraft

http://bugs.winehq.org/show_bug.cgi?id=18993

Anastasius Focht  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
      Fixed by SHA1|                            |2c0edb94e3da37a736b73f1a647
                   |                            |bd3c9863f2608
                 CC|                            |[e-mail]