Bug#564113: gimp-dds: Invalid borders generated around cubemap mipmaps

[Michalis Kamburelis]

Package: gimp-dds
Version: 2.0.7-1
Severity: normal

Open this file
https://vrmlengine.svn.sourceforge.net/svnroot/vrmlengine/trunk/kambi_vrml_test_suite/textures/castle_end_sequence.dds
Save as DDS selecting "Generate mipmaps" (all else by default, "As Cube
Map" is correctly selected as default). Open resulting DDS with mipmaps,
and you can see that all generated mipmaps have a non-matching 1-pixel
wide borders at the bottom and right (upper and left borders are Ok).

I guess when generating mipmaps, they take from the wrong side of cube
map for reference.

castle_end_sequence.dds is oriented correctly, as far as I know,
following Direct X left-handed (which seems to be standard for DDS)
orientation. Changing orientation to OpenGL right-handed (swapping
negative and positive Y) doesn't help, the invalid borders are still
generated (and always at the lower and right side of the mipmap).

I tested also on cubemaps included in
http://developer.amd.com/gpu/cubemapgen/pages/default.aspx , to make
sure it's not the fault of my castle_end_sequence.dds. And generating
mipmaps for them (e.g. Textures/CubeMaps/BlueSky512.dds) by gimp-dds
makes the same bug.

My resulting DDS file is on
https://vrmlengine.svn.sourceforge.net/svnroot/vrmlengine/trunk/kambi_vrml_test_suite/textures/castle_end_sequence_with_mipmaps.dds

I made a similar test with S3TC:
https://vrmlengine.svn.sourceforge.net/svnroot/vrmlengine/trunk/kambi_vrml_test_suite/textures/castle_end_sequence_s3tc_with_mipmaps.dds
and the S3TC version has the same problem. So this doesn't seem
related to S3TC. I also read these files by my own code, and the ugly
border is there --- so, again, the bug seems to happen when generating
mipmaps (not when reading DDS file).

Versions:
(exactly like my previous bug report today to gimp-dds):

I initially saw both problems with 2.0.7 (more precisely, 2.0.7-1
version of Debian package "gimp-dds"). I checked out and compiled trunk
(from http://nifelheim.dyndns.org/svn/gimp-dds/trunk ) and both bugs are
still there. (I don't see any changes in SVN since around the 2.0.7
release anyway.)

My gimp version is 2.6.7-1.1.

Submitted by email to upsteam author (mail at the bottom of
http://nifelheim.dyndns.org/~cocidius/dds/), without an answer,
so resubmitting to Debian hoping for a fix :)



-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 2.6.26-2-686 (SMP w/2 CPU cores)
Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages gimp-dds depends on:
ii  libc6                         2.10.2-2   GNU C Library: Shared libraries
ii  libgimp2.0                    2.6.7-1.1  Libraries for the GNU Image Manipu
ii  libglib2.0-0                  2.22.3-1   The GLib library of C routines
ii  libgtk2.0-0                   2.18.3-1   The GTK+ graphical user interface 

gimp-dds recommends no packages.

gimp-dds suggests no packages.

-- no debconf information