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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks! I believe the new depth peeling code is probably leaving the zbuffer in a different state than the opaque z buffer. If you get a second could you try the attached patch and see if it works for you. It is based on a more recent VTK but it is a tiny patch.</span></a></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Ken</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Ken Martin PhD</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Chairman & CFO</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Kitware Inc.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">28 Corporate Drive</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Clifton Park NY 12065</span></p><p class="MsoNormal"><a href="mailto:ken.martin@kitware.com"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">ken.martin@kitware.com</span></a><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">919 869-8871 (w)</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">This communication, including all attachments, contains confidential and legally privileged information, and it is intended only for the use of the addressee. Access to this email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken in reliance on it is prohibited and may be unlawful. If you received this communication in error please notify us immediately and destroy the original message. Thank you.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> vtk-developers [mailto:<a href="mailto:vtk-developers-bounces@vtk.org">vtk-developers-bounces@vtk.org</a>] <b>On Behalf Of </b>Xabi Riobe<br><b>Sent:</b> Thursday, September 24, 2015 5:29 AM<br><b>To:</b> VTK Developers<br><b>Subject:</b> [vtk-developers] Picking problem with OpenGL2 and DepthPeeling</span></p><p class="MsoNormal"> </p><div><p class="MsoNormal">Hi,</p><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">I try to pick in a scene that contains a translucent object and the pick fails if I use the OpenGL2 backend (v6.3.0), tested on VS2013 32 bits with nVidia Quadro 4000 (driver 353.30)</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">The same code works with OpenGL backend.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">I can reproduce it with the sample code attached, based on the example at <a href="http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/Picking">http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/Picking</a> with these lines added:</p></div><div><p class="MsoNormal"> </p></div><div><div><p class="MsoNormal"> renderer->SetUseDepthPeeling(1);</p></div><div><p class="MsoNormal"> renderer->SetMaximumNumberOfPeels(8);</p></div><div><p class="MsoNormal"> renderWindow->SetAlphaBitPlanes(1);</p></div><div><p class="MsoNormal"> renderWindow->SetMultiSamples(0);</p></div></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">and the opacity set to 0.5 for the plane.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">If i don't use depth peeling, or if the plane is opaque, the picker works as expected.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">It seems that the pick fails when in vtkOpenGLRenderer::DonePick the float value returned by GetZbufferData is 1.0</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"> </p></div></div></div></body></html>