[Octave-bug-tracker] [bug #51444] surf(): additional white lines in surface plot

[Hartmut]

URL:
  <http://savannah.gnu.org/bugs/?51444>

                 Summary: surf(): additional white lines in surface plot
                 Project: GNU Octave
            Submitted by: hardy
            Submitted on: Tue 11 Jul 2017 05:49:53 PM UTC
                Category: Plotting with OpenGL
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Inaccurate Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.1
        Operating System: Any

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Details:

This happens with Octave 4.2.1 and the OpenGL toolkits . Here is how to
reproduce it:


clear, close all;
graphics_toolkit qt % fltk is the same, gnuplot is fine

x = [-3:1:3];
y = x;
[xx, yy] = meshgrid(x,y);
zz = xx .* yy;
zz(zz < 0) = 0;

surf(xx, yy, zz, 'EdgeColor', 'none');
view(2);
grid off;


In the resulting (2d view on a) 3d surface plot, there are some additonal
white lines visible. (They are also visible in other 3d view orientations.)
Those white lines should not be there.

I have observed this with Windows 7 as well as with Ubuntu 16.04 linux.

The generated 3d plot of Matlab does not show those white lines. But I think
this is not only a compatibility issue, but an Octave plotting bug on its own.
Those white lines simply shouldn't be there, they spoil the appearance of the
whole 3d plot.

I will attach 3 screenshots from Octave results (under Win7 and Ubuntu 16.04)
as well as Matlab results (Win7).



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File Attachments:


-------------------------------------------------------
Date: Tue 11 Jul 2017 05:49:53 PM UTC  Name: Screenshot_Octave_Linux.png 
Size: 14kB   By: hardy

<http://savannah.gnu.org/bugs/download.php?file_id=41168>
-------------------------------------------------------
Date: Tue 11 Jul 2017 05:49:53 PM UTC  Name: Screenshot_Octave_Win7.jpg  Size:
87kB   By: hardy

<http://savannah.gnu.org/bugs/download.php?file_id=41169>
-------------------------------------------------------
Date: Tue 11 Jul 2017 05:49:53 PM UTC  Name: Screenshot_Matlab_Win7.jpg  Size:
95kB   By: hardy

<http://savannah.gnu.org/bugs/download.php?file_id=41170>

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