Whether or not the Depth Buffer exists is typically a function of the arguments used to create the GL context. You can create contexts without a Depth Buffer, but it's unusual.<br><br>other things to look into:<br>* Near-Far clipping Plane values .. have you tried calling renderer->ResetCameraClippingRange() ? if your near plane is too close to 0, you'll lose alot of resolution, causing artifacts.
<br>* Are you creating your own GL contexts? Or using the built-in VTK stuff?<br><br>Can you post ascreenshot of what's going wrong? <br><br><div class="gmail_quote">On Nov 28, 2007 8:51 AM, Peter Clifton <<a href="mailto:pcjc2@cam.ac.uk">
pcjc2@cam.ac.uk</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d"><br>On Wed, 2007-11-28 at 09:40 -0500, Jeff Lee wrote:
<br>> If these artifact are independent of whether you have opacity set or<br>> not, it is probably a depth-buffering issue. What happens when you<br>> setenv GL_DEPTH_BITS 32 and relaunch your app?<br>> -J<br>
<br></div>Converting to bash...<br><br>GL_DEPTH_BITS=32 ipython -wthread vtk_test.py<br><br>(Where vtk_test.py is the very short "Simple Example" at:<br><a href="http://scipy.org/Cookbook/MayaVi/mlab" target="_blank">
http://scipy.org/Cookbook/MayaVi/mlab</a><br><br>Its still bad from certain camera angles.<br><br>AHA... turning on MESA_DEBUG=1..<br><br>Mesa warning: glEnable(GL_DEPTH_TEST) but no depth buffer<br><br>It does seem like we have a guilty suspect. I'll bug the Intel driver
<br>guys to see if there _should_ be a depth buffer.<br><br>Thanks for the help... I'm sure I didn't see that message last time I<br>tried with MESA_DEBUG=1, perhaps the distro version wasn't built with<br>all debugging enabled. I've since built it myself from git HEAD.
<br><br>Is a depth buffer expected on GL Hardware??<br><br>Best wishes,<br><font color="#888888"><br>--<br></font><div><div></div><div class="Wj3C7c">Peter Clifton<br><br>Electrical Engineering Division,<br>Engineering Department,
<br>University of Cambridge,<br>9, JJ Thomson Avenue,<br>Cambridge<br>CB3 0FA<br><br>Tel: +44 (0)7729 980173 - (No signal in the lab!)<br><br>_______________________________________________<br>This is the private VTK discussion list.
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