Bug#564111: gimp-dds: Dark 1x1 mipmap for 2D texture

[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/016marbre.jpg
and save as DDS, checking "Generate mipmaps" (everything else default).
Look at mipmaps in the resulting file (e.g. open saved file back by
gimp-dds). The lowest 1x1 mipmap contains one almost black (color is
#1d1c1c) pixel.

Which is wrong --- the base image is obviously mostly white, so the
final 1x1 mipmap should be much lighter. Also, all the colors on
previous 2x2 mipmap are much *lighter* than #1d1c1c.

So something went wrong when generating (at least) this mipmap level.
Not sure whether 2x2 level is 100% correct either (it's a little too
dark anyway, although not as black).

My resulting DDS file is on
http://michalis.ii.uni.wroc.pl/~michalis/tmp/016marbre_with_mipmaps.dds

I also tried selecting both mipmaps and DXT1 compression, result is here:
http://michalis.ii.uni.wroc.pl/~michalis/tmp/016marbre_s3tc_with_mipmaps.dds
Result with S3TC compression has the same problem, so this
problem is not related to S3TC.

Oh, and I tested reading these DDS files with my own programs, and yes,
the last mipmap level *is* almost black. So it's not a problem in DDS
reader --- trouble happens at DDS writing, when mipmaps are generated.

Versions:

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