Bug 6098 - Wrong normals with GL_AUTO_NORMAL
Summary: Wrong normals with GL_AUTO_NORMAL
Status: RESOLVED MOVED
Alias: None
Product: Mesa
Classification: Unclassified
Component: Mesa core (show other bugs)
Version: 6.4
Hardware: x86 (IA32) Linux (All)
: high normal
Assignee: mesa-dev
QA Contact:
URL:
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Keywords:
Depends on:
Blocks:
 
Reported: 2006-03-03 00:30 UTC by Thomas Zimmermann
Modified: 2019-09-18 20:21 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
Testcase (8.44 KB, text/x-csrc)
2009-11-10 07:55 UTC, Thomas Zimmermann
Details

Description Thomas Zimmermann 2006-03-03 00:30:08 UTC
Hi,

i use 2d evaluators to draw a grid. The grid points are arranged, so that the
parameter u walks along +x and v walks along -z. Calling glEvalMesh() renders a
grid with front faces pointing upwards. (I tested this by explicitly culling
back faces.)
The grid patches normals where generated with GL_AUTO_NORMAL. I guess normals
should also point upwards, but the lighting in the scene behaves, as if normals
where pointing downwards.
Calling glFrontFace(GL_CW) reverses normals as expected, but they still point
into the wrong direction.

The system is Linux 2.6.13, Mesa 6.4.2 SW-Renderer on Xorg 6.7

Regards,

Thomas Zimmermann
tdz@users.sourceforge.net
Comment 1 Ian Romanick 2009-11-09 18:28:02 UTC
Are you still able to reproduce this bug?  Do you have a small test case?
Comment 2 Thomas Zimmermann 2009-11-10 07:55:13 UTC
Created attachment 31092 [details]
Testcase

The attached file contains a testcase for this bug. Instructions are included in the source file.

I reported this ages ago, so I'm not sure whether the testcase actually shows the same bug. Maybe I just misunderstood the behavior of the evaluator functions. However, the lighting in the testcase program still looks strange to me, so I guess the bug is still there.

Regards, Thomas
Comment 3 Thomas Zimmermann 2009-11-10 07:57:04 UTC
BTW, I'm on a Fedora 11 system with an Intel 945 graphics card.
Comment 4 GitLab Migration User 2019-09-18 20:21:43 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mesa/mesa/issues/954.


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