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<p>Dear VTK Users,</p>
<p>I would like to report a problem I am experiencing with the
OpenGL2 back-end and which does not occur under the OpenGL
back-end. I am using a custom filter that implements a level set
method for segmenting images, and I can display the evolution of
the level set process using VTK 5.10 or newer versions of VTK
configured to use OpenGL, but not under OpenGL2. <br>
</p>
<p>In the application there is a for loop where the level set filter
is set to run a small number of level set iterations (e.g. 5) and
than the visualization pipeline is updated to show the the zero
level set surface extracted with a vtkContourFilter. <br>
</p>
<p>The above worked fine under OpenGL but I get the following error
under OpenGL2<br>
<span style="color: rgb(0, 0, 0); font-family: Roboto, sans-serif;
font-size: 21px; font-style: normal; font-variant: normal;
font-weight: bold; letter-spacing: normal; line-height: 28px;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 1;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(249, 250,
252);"></span></p>
<p><img src="cid:part1.D0EBCAEF.8336A519@ne-scientific.com" alt=""></p>
<p>The above error occurs on the second visualization attempt<br>
</p>
<br>
<p>A Python snippet below shows the relevant code:<br>
</p>
<p><br>
</p>
<p><tt>ls.SetIter(5) # tell the filter to run 5 level set iterations
every time Update() is called</tt><tt><br>
</tt><tt><br>
</tt><tt>for i in range(num_cycles):</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> print("LS iteration %i of %i\n" % (i*5,
num_cycles*5))</tt><tt><br>
</tt><tt><br>
</tt><tt> ls.Modified() # set the modified flag on the level
set filter so that the Update() call results in a re-run</tt><tt><br>
</tt><tt> ls.Update() # run more iterations of the level set
filter</tt><tt><br>
</tt><tt> contour_filter.Update() # update the zero level set
surface</tt><tt><br>
</tt><tt> renWin.Render() # re-render the screen</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt>print("Terminated running LS iterations")</tt></p>
The environment in Windows 10 64bit, VTK 7.0.0, Python 3.5.1<br>
<br>
<br>
I will be happy to post a full source code example if that helps. <br>
<br>
Any comment is welcome,<br>
<br>
Thanks,<br>
<br>
Best Regards,<br>
<br>
Andrea<br>
<br>
<br>
<pre class="moz-signature" cols="72">-- </pre>
<pre class="moz-signature" cols="72">
++++++++++++++++++++++++++++++++++++
Andrea Borsic Ph.D.
Founder NE Scientific LLC
Tel: +1 603 676 7450
Web: <a class="moz-txt-link-abbreviated" href="http://www.ne-scientific.com">www.ne-scientific.com</a>
Twitter: <a class="moz-txt-link-freetext" href="https://twitter.com/ne_scientific">https://twitter.com/ne_scientific</a></pre>
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