[Python-apps-team] Bug#478880: mayavi2: Opacity == 1.0, but still slightly transparent

[Francesco Poli]

Package: mayavi2
Version: 2.1.1-2
Severity: normal

Hi!

I noticed a little problem in opacity management.

Please note that I've recently upgraded mayavi2 from version 2.1.1-2 to
version 2.1.1-2+b1, but I've seen the same issue with version 2.1.1-2.

Let's consider (one more time!) the test case I prepared for bug #400406
(see [1] and [2]).

[1] http://bugs.debian.org/400406
[2] http://bugs.debian.org/cgi-bin/bugreport.cgi/vtk-multiblockPLOT3D-bug-test.tar.gz?bug=400406;msg=5;att=1

  $ tar xvzf vtk-multiblockPLOT3D-bug-test.tar.gz
  $ ls
  gen_tinyplot3d.f  tiny.q    vtk-multiblockPLOT3D-bug-test.tar.gz
  list_plot3d.py    tiny.xyz
  $ mayavi2

The main window shows up.

 * from menus, select File -> Load data -> PLOT3D file
 * as XYZ Co-ordinate file, select `tiny.xyz'
 * as Q Solution file, select `tiny.q'
 * select PLOT3D:tiny.xyz, tiny.q  in the MayaVi pane
 * in the PLOT3DReader tab (inside the object editor), check "Binary
file", "Do not reduce number of outputs", "Has byte count", and "Multi
grid"; *un*check "Force read", "I blanking", and "Two dimensional
geometry"; select "little_endian" Byte order
 * in the Reader tab, click on the "Update Reader" button
 * from menus, select Visualize -> Modules -> Surface (a blue square
shows up in the TVTK scene)
 * rotate the TVTK scene (by moving the mouse with the left button
pressed)

I should only see at most three cube faces (if perspective theory
is my friend...).
Nonetheless, I can also see the remaining faces, behind the directly
visible ones.
Let me check the opacity settings:

 * in the MayaVi pane, double-click on Surface

Mmmmh, Opacity is set to 1.0.  Hence I should only see directly
visible faces.  Yet, I seem to have Superman X-ray view!  ;-)

Saving the scene to a PNG image, shows that the problem will affect
visualization outputs, as well.
It really seems I'm getting (partial) transparency, even when I do
_not_ want it...  :-(

I think this is bug.


-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.24-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages mayavi2 depends on:
ii  libc6                        2.7-10      GNU C Library: Shared libraries
ii  python                       2.5.2-1     An interactive high-level object-o
ii  python-central               0.6.6       register and build utility for Pyt
ii  python-enthought-traits      2.0.4-2     Manifest typing and reactive progr
ii  python-enthought-traits-ui   2.0.4-2     User interface related modules for
ii  python-numpy                 1:1.0.4-7   Numerical Python adds a fast array
ii  python-pkg-resources         0.6c8-3     Package Discovery and Resource Acc
ii  python-vtk                   5.0.4-1+b1  Python bindings for VTK
ii  python-wxgtk2.6              2.6.3.2.2-2 wxWidgets Cross-platform C++ GUI t
ii  python2.5                    2.5.2-3     An interactive high-level object-o

mayavi2 recommends no packages.

-- no debconf information